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Memory Professor System Summary

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Behavioural Paradigms for Studying Aversive Memories

For human beings, two different memory categories have been introduced. According to Schacter, implicit (or unconscious unaware) memory is revealed when previous experiences facilitate performance on a task that does not require conscious or intentional recollection of those experiences. Explicit memory, in turn, is revealed when the performance of a task requires conscious recollection of previous experiences. These are descriptive concepts that are primarily concerned with a person's psychological experience at the time of memory retrieval. Accordingly, the concepts of implicit and explicit memory neither refer to nor imply the existence of two independent or separate memory systems (Schacter 1987). As these two memory categories cannot be easily applied to the situation in animals, they will not be further considered in this chapter.

Acute adverse effects of cannabis

Undoubtedly those that give the greatest concern in considering its medical uses (7R, 8RS, 10ER). All of the CNS effects of THC, both the desired medical actions and the undesired psychological effects, appear to be mediated through a single type of brain receptor, the CB1 cannabi-noid receptor. This was illustrated, for example, by a well-controlled study in 63 healthy cannabis users, who received either the CB1 receptor antagonist rimonabant (SR141716A) or placebo and smoked either a THC-containing or a placebo marijuana cigarette (12C ). Rimon-abant blocked the acute psychological effects of the active cigarettes, but when given alone (with placebo cigarettes) produced no significant psychological effects. In many of the medical applications that have been assessed to date, unwanted psychological adverse effects have been blamed as the main cause of patients' rejection of the drug as unacceptable. Patients who have had no prior experience with cannabis often find its intoxicant...

Psychological psychiatric

Anticholinergic drugs can impair short-term memory. The effects in non-demented patients are reversible, receding within a few weeks of withdrawing treatment (3). Comparisons of dopaminergic drugs with anticholi-nergic drugs in healthy volunteers have shown that antic-holinergic drugs caused significant impairment of memory function, more confusion, and dysphoria (SEDA-13, 115).

CB1 Cannabinoid Receptors Participate in the Control of Cognitive Functions

Cannabinoid ligands produce clear effects on learning and memory that have been widely reported (Dewey 1986 Ameri 1999 Diana and Marty 2004). However, the precise role of the endocannabinoid system on these processes has not yet been completely clarified. In humans, THC administration induces the disruption of short-term recall, as well as disorienting effects (Miller and Branconnier 1983 Chait and Perry 1992). In animals, cannabinoid administration impairs memory and learning processes. In particular, there are reports that cannabinoids impair task acquisition and working memory in different animal species (Molina-Holgado et al. 1995 Lichtman and Martin 1996 Winsauer et al. 1999). The alterations are especially important for spatial memory (Molina-Holgado et al. 1995 Lichtman andMartin 1996) and short-term memory (Molina-Holgado etal. 1995). Inrodents, endogenous cannabinoids have been reported to prevent the induction of long-term potentiation in the hippocampus (Stella et al....

The Physical And Psychological Effects Of Marijuana

Difficulty in following a train of thought, and short-term memory loss. Many studies support THC's medicinal capacity to ease pain and nausea, decrease ocular pressure, and control convulsions. Typical psychological effects are anxiety, panic attacks, feelings of paranoia, confusion, relaxation and stress Harry and Rod may not know that they could be smoking their future away. Marijuana has been shown to affect short-term memory and learning functions of the brain. Also, a person who is high has difficulty learning and retaining important information while in school. If Harry and Rod get arrested for possessing or using pot, they may not be eligible for student loans, small business loans, farm subsidies, or government grants. This could affect their future ability to attend college or start up a business. The short-term effects of marijuana use include an impairment of short-term memory and learning. A survey of 12- to 17-year-old students found a correlation between past-year...

Overview of Acute Effects

Cannabis intoxication alters thoughts. The exact extent of the alteration varies with dosage, setting, experience, and other factors. Higher doses in novel, laboratory settings may produce dramatic impairment on some tasks, particularly in people who have little experience with the drug. Cannabis has a varied impact on different measures. Generally, marijuana does not alter performance on easy tasks but impairs complex ones. For example, simple learning tasks like memorizing pairs of words show little change during intoxication. Memory for material learned prior to intoxication also remains intact while participants are high. For example, participants who memorize a list of words

Acute Health Effects Of Cannabis

Cannabis produces euphoria and relaxation, alters perception, distorts time, and intensifies ordinary sensory experiences, such as, eating, watching films, appreciating nature, and listening to music. Users' short-term memory and attention, motor skills, reaction time and skilled activities are impaired while they are intoxicated (Hall & Pacula, 2003 Iversen, 2007). These effects develop rapidly after smoking cannabis and typically last for 1 to 2 hours (Iversen, 2007). Their onset is delayed for 1 to 4 hours after oral use (Iversen, 2007). 1994). Specifically, it slows reaction time and information processing, and impairs perceptual-motor coordination, motor performance, short term memory, attention, signal detection, and tracking behaviour (Ramaekers et al., 2004 Solowij, 1998). These effects increase with THC dose, and are larger and more persistent in tasks requiring sustained attention (Solowij, 1998).

Summary of Acute Effects

In general, marijuana intoxication has little impact on learning simple tasks or remembering information mastered prior to ingesting the drug. Intoxicated people can probably still become proficient at new, easy skills. They can probably recall events that occurred before they smoked marijuana, including important information from the distant past. The drug has produced inconsistent effects on simple reaction time, disinhibition, and vigilance. Sometimes the drug slows reaction time, makes people unable to restrain their first impulse, and prevents them from sticking with long, dull tasks. Marijuana intoxication clearly impairs aspects of memory, perception, reading, arithmetic, and complex reaction time. After smoking cannabis, people cannot memorize new lists of words, distinguish among similar colors, read complicated passages aloud, subtract strings of numbers, or respond quickly to different lights by pressing different buttons.

Cannabinoid Receptor Antagonists

There are several reports that SR141716A produces effects that are opposite in direction to those produced by cannabinoid receptor agonists (cf. Sections 5 and 6). More specifically, when administered alone, SR141716A has been found to produce hyperkinesia in mice (Compton et al., 1996), provoke signs of increased arousal in rats (Santucci et al., 1996), improve social short-term memory in rats and mice (Terranova et al., 1996), augment cyclic AMP production in cells transfected with cannabinoid receptors (Felder et al., 1995), increase the amplitude of electrically-evoked contractions of isolated tissue preparations (Coutts et al., 1995 Coutts and Pertwee, 1996 Pertwee and Fernando, 1996 Pertwee et al., 1996b) and enhance electrically-evoked neurotransmitter release in rat hippocampal slices (acetylcholine), the myenteric plexus of guinea-pig small intestine (acetylcholine) and guinea-pig retinal discs (noradrenaline and dopamine) (Coutts and Pertwee, 1996, 1997 Gifford and Ashby,...

Treatment Options for Insomnia

Benzodiazepines Named for their chemical structure, they are the most frequently used class of medication for insomnia because of their effectiveness and their minimal side effects with short-term use. Common side effects include short-term memory problems and poor coordination, but these are usually minimal. Due to the marketing pitches of drug companies, several have become popular for sleep, but all the drugs in this class can be used.

Treatment of Insomnia in Medical and Psychiatric Conditions

Stress If a sudden stressful situation is impairing your sleep, medication may be the fastest and best way to get the rest you need. Hypnotics or benzodiazepines are invariably effective. Both can cause short-term memory problems, and benzodiazepines can impair muscle coordination (leading to an increased risk of car accidents and falls). Benzodiazepines are habit-forming and lose their effectiveness with nightly use, so don't take them for more than four weeks. Anxiety Insomnia often accompanies acute anxiety about an issue in your life. Hypnotics and benzodiazepines are reasonable aids in acute anxiety. Both can cause short-term memory problems, and benzodiazepines can impair muscle coordination (leading to an increased risk of car accidents and falls). Benzodiazepines are habit-forming and lose their effectiveness with nightly use, so don't take them for more than four weeks. In general, when depression is adequately treated with antidepressants, sleep will improve. In severe...

Cannabinoid Receptors And Brain Functions

For example, scientific and anecdotal research shows that marijuana can impair coordination and other motor skills in humans. (As with other effects, these are dose-dependent.) The highest number of CB1 receptors can be found in the basal ganglia, a part of the brain that regulates body movements. CB1 receptors are also abundant in the cerebellum, which is responsible for coordination and movement the hippocampus, which is involved in the learning process, memory, and response to stress and the cerebral cortex, where higher cognitive functions such as problem-solving are integrated. Short-term memory loss has been associated with temporary lesions that form in the hippocampal region of the brain.

Intoxication During Testing

Every day for years may be unlikely to stop simply because a scientist wants them to draw lines, arrange blocks, and memorize words. Without this abstinence, the comparison between chronic users and nonusers essentially becomes a study of intoxication. Given the data on acute effects, studies of chronic effects must clearly occur when all participants are no longer under the influence of the drug. Otherwise, any deficits in chronic users could arise from their current intoxication instead of any impact of long-term consumption. Ensuring this abstinence is extremely difficult when studying people who smoke daily. Inpatient stays in a hospital may help solve this problem. Participants would have to agree to remain in the hospital and avoid drugs for a specified period prior to testing. At least one recent study used this strategy and still found deficits associated with chronic smoking (Pope & Yurgelun-Todd, 1996).

Cognitive development

Much research has been devoted to the cognitive and behavioral effects of marijuana on adolescents and adults. Many of the effects described earlier involved the performance of a complex combination of cognitive and motor skills. A 1995 study by the Australian government titled The Health and Psychological Consequences of Cannabis Use found that heavy marijuana use may produce subtle cognitive impairment. Marijuana appears to have its greatest effect on short-term memory. According to a 1993 article titled Chronic Marihuana Smoking and Short-term Memory Impairment, marijuana use in adolescents may also result in long-term memory impairment. Evidence from a 1996 study in the Journal of the American Medical Association titled The Residual Cognitive Effects of Heavy Marijuana Use in College Students suggests that chronic marijuana use over many years may cause subtle reductions in attention as well as in the ability to organize and make sense of complex information. According to a 1995...

Cannabinoid Receptors

Cannabinoids affect cognitive and motor functions. Their subjective effects are well documented by chronic users and include enhancement of senses, errors in time and space judgment, emotional instability, irresistible impulses, illusions, and even hallucinations. Objective effects have been measured and studied, and decreased psychomotor performance, interference with attention span, and loss of efficiency in short-term memory are classically reported in the literature. Cannabinoids also have a number of peripheral effects, notably vasodilatation, tachycardia, and immunosuppressant properties. This chapter explains the neurophysiological and anatomical bases of these disorders and correlate them with what is known of the cannabinoid receptors.

Neural Mechanisms of Anxiety and Fear

A variety of behavioral and electrophysiological data has led LeDoux and colleagues to propose a model to explain how neural responses to the CS and US in the LA could influence LTP-like changes that store memories during fear conditioning. This model proposes that calcium entry through N-methyl-D-aspartate (NMDA) receptors and voltage gated calcium channels (VGCCs) initiates the molecular processes to consolidate synaptic changes into long-term memory (Blair et al. 2001). Short-term memory requires calcium entry only through NMDA receptors and not VGCCs. This hypothesis leads to several predictions that may have relevance to the discovery of novel therapeutics for anxiety disorders. It suggests that blocking NMDA receptors in the amygdala during learning should impair short-and long-term fear memory. This has been demonstrated in rodents (Walker et al. 2000 Rodrigues et al. 2001). Valid human models of fear conditioning and the availability of the NMDA...

Hippocampus and Memory Impairment

Classically, memory is associated with the hippocampus. But in reality, the basal ganglia and the cerebellum are also involved in formulating and retrieving memories. There are two different types of memories, referred to as declarative and procedural. Declarative memory is the storage and retrieval of material available to the conscious mind. It is encoded in symbols and can be expressed as language (hence, declarative), for example, remembering someone's name, a phone number, or an appointment date. The hippocampus and association cortex are critical in declarative memory. Procedural memory is not available to the conscious mind. It is about things we do not think of. Such memory involves skills and associations that are occurring unconsciously, for example, riding a bicycle, driving a car, or playing a piece of piano music. When we perform a complex action, we do not need to be conscious of a particular memory, and even thinking about it may actually inhibit the ability to perform...

Pregnancy Category None

Tests using medical-size doses (which may be smaller than ones taken by illicit users) reveal no impairment of mental or physical abilities the researchers concluded that GHB does not hurt job performance or ability to drive a car. Nevertheless, GHB is suspected of causing an automobile driver to pass out, and the drug's sleep-inducing properties make it inadvisable to use while operating dangerous machinery. Supposedly the drug causes amnesia about events that occur while a person is intoxicated with the substance, although experiments using medical-size doses find no effect on short-term memory. A large-enough dose can slow heart rate and interfere with a person's ability to move and make a person vomit and fall asleep. Breathing difficulty can occur. Seizures have been reported, but some authorities believe those reports have misidentified various muscle contractions as seizures. In monkeys the drug lowers body temperature. In rats that effect depends on a dose's size,...

Receptor for Associative Learning and Memory

In a5 (H105R) mice, the point mutation was without major effect on the pharmacology of diazepam. Surprisingly, however, the content of a5 GABAA receptors was reduced by 30 -40 exclusively in the hippocampus (Crestani et al. 2002). The remaining hippocampal a5 receptors showed a normal wild-type distribution. There was no indication for adaptive changes of other GABAA receptors expressed in the same pyramidal cells (Crestani et al. 2002). Be-haviourally, the partial deficit of hippocampal a5 GABAA receptors resulted in an improved performance in trace fear conditioning, a hippocampus-dependent task in which a conditioned stimulus has to be memorized for a period of time sufficiently long to be associated with an unconditioned stimulus given after a silent time lag (trace of 1 s). These results pointed to a role of a5 GABAA receptors in the function of temporal memory. When the a5 GABAA receptors were deleted in the entire brain by targeting the a5 subunit gene (Collinson et al. 2002...

Explicit Learning And Memory

Learning occurs in two fundamental forms conscious and unconscious. With conscious learning, which psychologists also call explicit learning, we use our senses to find out what is in the world and where and when events have occurred. We take in information about what we see, hear, smell, taste, and touch, and our brain stores that information in its short-term, or working, memory. Our brain's working memory allows us to retain information long enough to perceive it, use it, perhaps mull it over a bit, and then either store or discard it. For example, as you enter the supermarket to buy the things you need for tonight's big dinner, you walk through the aisles to see what else looks appealing. As you head for the tomatoes, you keep a mental note of where these things are located. After picking out the tomatoes, you head back to pick up the fresh-looking lettuce and the crisp green beans you saw earlier. You selected these things because you had noticed they looked fresh, stored that...

Marijuana and Cognition in

Cognitive differences were revealed in a study on 1,600 Egyptian prisoners (Soueif 1976). In this study, 16 different measures were recorded, of which 10 revealed impairment in the user group, while 2 showed better performance. However, the selected groups were not well controlled and many of the critiques listed below apply to this investigation. Similarly, deficits in IQ, memory, time estimation and reaction times were reported in several studies performed in India (Wig and Varma 1977 Menhiratta et al. 1978). Finally, investigations on college students with at least twice weekly marijuana consumption revealed deficits in memory formation, specifically deficits in information transfer into long-term memory (Gianut-sos and Litwack 1976 Entin and Glodzung 1973). However, a later study did not confirm these memory impairments (Rochford et al. 1977). More recent studies on cognitive deficits in marijuana users collectively suggest that impairments are (1) predominant for the attentional...

Cannabinoids Modulate Cognition in Animal Models

Guided by the older work from humans, research into the behavioural effects of cannabinoids concentrated on the disruption of working and short-term memory formation. This is in agreement with data suggesting marijuana-induced increases in CBF in paralimbic regions of the frontal lobes and the cerebellum, but reduced blood flow in the temporal lobe (O'Leary et al. 2002). Hypoactivity in the temporal lobe may constitute the neural basis of cognitive alterations seen in cannabis users and has prompted the search for the underlying mechanisms using behavioural paradigms that specifically activate the medial temporal lobe, or using electro-physiological recording protocols in medial temporal lobe structures. It is also in line with reductions of the cortical P300 amplitude in marijuana addicts. The P300 is an ERP reflecting attentional resource allocation and active working memory (Johnson et al. 1997). Similarly, monkeys treated with A9THC chronically have predominantly slow-wave EEGs...

Role of the endocannabinoid system in learning and memory

One strategy for investigating the role that the endocannabinoid system may play in learning and memory processes is through the use of animal learning models. While it is certain that exogenous administration of an agonist cannot closely mimic the actions of an endogenous system tightly integrated within neural circuits sensitive to specific spatio-temporal contexts, useful information about the endogenous system can be taken from these studies. For example, those particular memory tasks that are particularly sensitive to disruption by exogenous agonists may provide insight into processes that are modulated by endocannabinoids. Conversely, endocannabinoids are probably not crucial to aspects of memory that are insensitive to disruption by exogenous agonists. So which aspects of learning and memory appear most sensitive to agonists The most consistent delineation made regarding the effects of CB1 agonists is that they tend to disrupt aspects of short-term (i.e. working) memory, while...

Delayed Matchto Position Tasks

Different from the short-term memory tested in the radial arm maze are the delayed match-to-position (DMTP) or delayed match-to-sample (DMTS) tasks that employ standard conditioning chambers. In the most frequently used version, rats learn to press a lever during the sample phase and press the same (match) or opposite (non-match) lever during the choice phase. Task difficulty is modulated by the introduction of a delay between sample and choice phase (0-45 s) performance falls to chance at delays exceeding 45 s (Deadwyler et al. 1996). The laboratories of Hampson and Deadwyler have extensively studied hippocampal involvement in this task (Hampson et al. 1999a) and determined learning-related single unit activity of ensembles of CA3 and CA1 neurones during the different phases of the task (Deadwyler and Hampson 1999 Deadwyler et al. 1996 Hampson and Deadwyler 1996 Hampson et al. 1993, 1999b). In summary, distinct hippocampal pyramidal cells fire during the sample, delay and match...

Other Memory Paradigms

Another test for short-term memory, but with a different psychological quality, is object recognition (Ennaceur and Delacour 1988). During acquisition, animals are exposed to a novel environment containing object A, and are tested during re-exposure to object A plus first-time exposure to novel object B, after minutes or hours. The time spent exploring each object in the test session is an index of short-term memory for A. Good memory is characterised by preferential exploration of B, bad memory by exploration of A. Brain structures involved in

Fear Conditioning and Ca2Signaling

Calcium is an important mediator of neuronal plasticity and increased intra-cellular Ca2+ is a key intermediate in activity-induced activation of protein kinases in many systems. Regulation of Ca2+ signaling in the amygdala appears to be important for fear memory, and dependence on NMDA receptors and voltage-gated calcium channels (VGCC) has been demonstrated for fear conditioning and for LTP in the amygdala. The acquisition of fear conditioned responses is inhibited by NMDA receptor blockade (Campeau et al. 1992 Fanselow and Kim 1994 Miserendino et al. 1990) and this can be shown with a NR2B subunit-specific antagonist that does not appear to disrupt normal synaptic transmission (Rodrigues et al. 2001). Mice with regulated expression of a CaMKII transgene or that are deficient in a CaMKII or CaMKIV signaling have impaired long-term memory of fear conditioning (Kang et al. 2001 May-ford et al. 1996 Silva et al. 1996). Bauer et al. (2002) have shown that blocking NMDA receptors in the...

Fear Conditioning and cAMPSignaling

CAMP signaling is important to many forms of neural plasticity including learning and memory (Silva et al. 1998), and evidence suggests that this signaling pathway is an regulator of the RNA and protein synthesis that regulate long-term fear memory and late-phase LTP in the amygdala. As with other forms of memory, fear memory can be divided into two temporal phases short-term (STM), which is protein synthesis independent and a long-lasting form, which requires RNA and protein synthesis (Davis and Squire 1984). LTP similarly occurs in distinct temporal phases also with only the late phase (L-LTP) requiringmacromolecular synthesis (Huang et al. 1994 Kandel 1997). The consolidation of fear memory but not STM, is blocked by inhibitors of protein synthesis or PKA (Bourtchuladze et al. 1998 Schafe et al. 1999), and this has been shown specifically in the lateral basolateral amygdala (Schafe and LeDoux 2000). Long-term fear conditioning is enhanced when concentrations of cAMP are...

Organs and Systems Respiratory

Lorazepam shares with other benzodiazepines the ability to impair explicit memory, but has a distinct further effect on implicit memory as well (7). However, it impairs memory more than its chemically and kinetically similar analogue, oxazepam (8). The effects of lorazepam 2.5 mg and diazepam 0.3 mg kg on explicit and implicit memory tasks have been examined in 24 men and 24 women randomly allocated to lorazepam, diazepam, or placebo (7). An implicit word-stem completion task and explicit memory tasks of immediate and delayed word recall and word recognition were administered 90 minutes after drug administration. Both diazepam and lorazepam significantly impaired performance on explicit memory measures. Only lorazepam significantly impaired performance on the implicit memory task.

Hypophyseotropic Peptides CRF Somatostatin

Wu et al152 demonstrated that the local injection of an antisense oligonucleotide against CRF into the hippocampus significantly impaired the retention performance of an inhibitory avoidance task in rats. Experiments performed by Liebsch et al,69 in which antisense oligodeoxynucleotides corresponding to either the rat CRF1 or CRF2 receptor mRNA were infused chronically via osmotic minipumps into the lateral ventricle. The rats were subjected to social defeat and immediately afterwards tested on the elevated plus-maze. CRF1 receptor antisense oligodeoxynucleotide infusion was found to exert an anxiolytic-like effect, whereas CRF2 receptor antisense oligodeoxynucleotide infusion had no effect on defeat-induced anxiety-related behavior. In contrast, the CRF2 receptor antisense oligodeoxynucleotide increased immobility in a forced swim test. No influence of either oligodeoxynucleotides was found on general locomotor activity in an open field or on short-term memory performance in a social...

Organs and Systems Psychological psychiatric

An important behavioral adverse effect of benzodiazepines, hostility and aggression in response to provocation, is less common with oxazepam than with its closely related analogue lorazepam (2). In a study of the effects of oxazepam on implicit versus explicit memory processes, as a function of time-course the effects of oxazepam (30 mg) or placebo on directly comparable tests of implicit memory and explicit memory were examined at three times in 60 healthy volunteers. Before the plasma concentration had peaked, oxazepam impaired cued recall performance relative to placebo but did not impair priming. At the time of the peak, oxazepam impaired performance in both memory tasks. After the peak, cued recall performance in the oxa-zepam group remained significantly impaired relative to placebo. However, oxazepam-induced impairments in priming were only marginal, suggesting that oxazepam-induced impairments in implicit memory processes begin to wane after theoretical peak drug...

Measurement of Cannabis Effects

Attention and cognition are broad psychological terms that include many specific functions involving higher order cognitive processing. Attentional processes involve searching, scanning, and detecting visual or auditory stimuli for brief or extended periods of time. These can be categorized as focused, selective, divided, or sustained attention (30). Cognitive processes involve learning, memory, problem solving, and reasoning skills. Such distinctions are somewhat arbitrary because any memory task requires attention and memory skills, as well as other cognitive resources. Acute cannabis administration impairs many aspects of attention and cognition, as described below and reviewed elsewhere (26-28) (see Note 11). As with psychomotor performance, cognitive impairment can last for up to 24 h after smoking cannabis (31).

Cognitive and Psychomotor Effects

Impairment of short-term memory and learning impairment following marijuana use is probably the most frequently reported and validated behavioral effect of marijuana use, and one for which there is the most consistent evidence. The link between memory impairment and driving impairment is, however, difficult to make convincingly. The strongest argument is the contribution of memory impairment to focus and selective attention. A clear recollection of recent events contributes to organizational and planning ability and promotes goal-directed behavior and action, allowing the subject to devote available cognitive capacity more efficiently to the driving task.

Hippocampal removal and residual memory

One of the longest standing controversies with respect to the role of the hippocampus in behavior is whether hippocampal activity is involved in the processing of spatial or nonspatial information (Cohen and Eichenbaum, 1993 Deacon and Rawlins, 1995 O'Keefe and Nadel, 1978 Nadel, 1991 Muller, 1996 Murray and Mishkin, 1998). In past years, this distinction has existed primarily in the rodent literature, but evidence is rapidly accumulating to extend this controversy to nonhuman primate and even human studies (Tulving and Markowitsch, 1997 Vargha-Khadem et al., 1997 Squire and Zola, 1997 Wagner et al., 1998 Brewer et al., 1998 Stern et al., 1996). We recently examined this issue by assessing the effects on short-term memory in two operant versions of delay tasks, matching (DMS) and nonmatching (DNMS) to sample in rats with selective ibotenate lesions of the hippocampus (HIPP) and in rats with lesions that encroached on retrohippocampal (HCX) structures (Hampson et al., 1999). In HIPP...

Chronic Exposure To Cannabinoids Attenuates Effects On Shortterm Memory

A striking paradox uncovered in our initial investigation of chronic cannabinoid treatment on short-term memory was the marked attenuation in the acute disruptive effects that occurred over a 20-30 day period of daily exposure to high doses (10mg kg) of A9-THC (Deadwyler et al, 1995b). It is well known that the half-life of A9-THC in rats is quite long (10-100 days), and that repeated daily dosing leads to accumulation of the drug in fatty tissue and re-release of active metabolites as well as primary compound (Dewey, 1986). Remarkably, animals initially unable to even locomote due to the severe catalepsy induced by the large (10 mg kg) dose of A9-THC (Abood et al., 1993 Abood and Martin, 1992), showed systematic improvement in DMS performance and finally complete tolerance to the same large dose after 35 days of exposure. The curves in Figure 23.6 show a predominantly delay-dependent effect of A9-THC on days 5 and 16, and fewer correct trials even at the shortest delays. By day 35,...

Cannabinoid Research Utilizing MRI

Functional Studies As of March 2004, there have been no peer-reviewed papers utilizing BOLD fMRI to examine functional changes in brain after acute or chronic marijuana. However, a recent meeting abstract hints at the wealth of information that remains to be gathered using this powerful technique. This preliminary study reported that marijuana users had decreased brain activation in cerebellar vermis and dorsal parietal cortex compared to normal control subjects during a visual attention task. Additionally, marijuana users were reported to show exposure-dependent decreases in relative BOLD signal in the cerebellar vermis (Chang et al. 2003). A pilot study of working memory in cannabis smokers, tobaco smokers and non-smoking controls has recently appeared (Jacobsen et al. 2004).

Disturbances of psychomotor function

Beta-adrenoceptor antagonists impair performance in psychomotor tests after single doses. These include effects of atenolol, oxprenolol, and propranolol on pursuit rotor and reaction times (150,151). However, other studies with the same drugs have failed to show significant effects (152-156), and the issue has remained controversial. A report that sotalol improved psychomotor performance in 12 healthy individuals in a dose of 320 mg day but impaired performance at 960 mg day (157) has been interpreted to indicate that the water-soluble beta-adrenoceptor antagonists would be less likely than the fat-soluble drugs to produce nervous system effects. Both atenolol and propranolol alter the electroencephalogram atenolol affects body sway and alertness and propranolol impairs short-term memory and the ability to concentrate (158,159). These results suggest that both lipophilic and hydrophilic beta-adrenoceptor antagonists can affect the central nervous system, although the effects may be...

Medical And Behavioral Toxicity Overview

In tolerance, followed by an increased long-term consumption that likely leads to tissue damage. Physical dependence may also develop, manifested by a withdrawal syndrome on sudden cessation of drinking. The brain damage, when severe, is usually classified as one of two main disorders. The first is a type of global (general) dementia. It is estimated that 20 percent of those individuals admitted to state mental hospitals suffer from alcohol-induced dementia (Freund & Ballinger, 1988). The second is an alcohol-induced amnestic (memory-loss) syndrome, more commonly known as Wernicke-Kor-sakoff syndrome. This is related to thiamine (Vitamin B1) deficiency. The Wernicke component refers to the acute neurologic signs, which consist of ocular (eye) problems such as a sixth cranial nerve palsy (disturbed lateral gaze), and ataxia (gross incoordination of muscle movements) the Korsakoff component refers to the memory impairment, which tends to be selective for short-term memory and is...

How Can K Channels Contribute to Learning and Memory

Have quinine and TEA sensitivity reminiscent of the slow activating Shab Kv2 series of voltage gated channels. In the Leonardo (Leo) mutant, flies are deficient in one isoform of 14-3-3, a family of proteins with pleiotropic effects that is conserved from yeasts to mammals. Leonardo flies have deficits in olfactory learning and short-term memory.115 At the neuromuscular junction, the leo protein may interact with the K+ channel Slo subunit via a calcium-binding protein called Slob.146 There may also be in vivo interaction with the eag subunit. Leo is expressed in the mushroom bodies, but its interactions with K+ channels at this site are unknown.

Effects on the Brain Cognitive Psychological and Mental Consequences

Research by Pope and Yurgelum-Todd (52), Kouri et al. (53), Solowij et al. (54), and Block and Ghoneim (55) has shown that chronic use of marijuana was associated with impairment of cognition, particularly affecting short-term memory and executive functioning in humans and this impairment did not recover after abstaining from heavy use of marijuana (up to 5000 times in a lifetime) for at least 24 hours (52), 7 days (56), or 6 weeks (54). However, in the study of Pope and colleagues (57), the subjects did recover after 28 days of abstinence from marijuana use. In studies by Pope and colleagues (52,56,57), the subjects smoked marijuana up to 5000 times in their lifetime (8-15 years), whereas in the study by Solowij et al. (54), the subject had smoked approx 6 g of marijuana each day for about 17 years. Many other older studies have also reported that marijuana use is associated with impairment of short-term memory and not old memory. cannabis for an average of 34 years the younger...

Bacopa monniera Wettst

Clinical studies have so far only been undertaken on healthy volunteers. In one double-blind, placebo-controlled study with normal healthy subjects treated with B. monniera extract, no acute effects on cognitive function were observed 145 . However, a double-blind, randomised, placebo-controlled study on patients aged 40 to 65 years showed that those given a standardised extract of B. monniera resulted in a significant improvement in retention of new information but no difference in the rate of learning, attention, and verbal and visual short-term memory 146 . Another similar study investigated the speed of visual information processing, learning rate and memory consolidation and concluded that the B. monniera extract improved higher-order cognitive processes such as learning and memory 147 .

Effects of Cannabinoids on the Brain

An interesting approach in utilising PET is its combination with cognitive tasks. While subjects perform verbal memory recall tasks, they are monitored in the scanner. Relative to controls, frequent marijuana users presented with reduced memory-related blood flow in prefrontal cortex, but increased CBF in hippocampus and cerebellum (Block et al. 2002). These alterations were paralleled by an increased recency effect, suggesting that users rely on short-term memory and thus fail in multiple trial learning tasks, while control subjects encode and retrieve episodic memory. Consequently, it may be argued that chronic marijuana use leads to a reconfiguration of memory processing. Reductions in prefrontal CBF are consistent with deficits in working memory.

Ontogeny of the Endogenous Cannabinoid System

This hypothesis is supported by the demonstration of a role for CB1 receptors in neurite remodeling in vitro (Zhou and Song 2001). Support also comes from the findings that endocannabinoids inhibit both cortical neuron differentiation to mature neurons using in vitro cellular models and adult hippocampal neurogenesis in vivo (Rueda et al. 2002). The endocannabinoids interfere with nerve growth factor (NGF) signaling that is responsible for the activation of the differentiation program by acting via CB1 receptors to inhibit NGF-induced signaling events that ultimately result in inhibition of neural generation (Rueda et al. 2002). Therefore, inhibition of neurogenesis in adult hippocampus, triggered by cannabinoids either during development or in the adult, might help to explain cannabinoid-related disruption of cognitive processes such as learning and short-term memory.

Receptors that Inhibit Adenylyl Cyclase

Stimulation of 5-HT1A receptors has controversial effects on working memory.60-130 When coadministered intrahippocampally with scopolamine, NAN-190, another 5-HT1A antagonist, is able to reduce scopolamine-induced working memory impairments.99 There is however no direct reciprocal interaction since physostigmine, a cholinesterase inhibitor generally able to compensate cholinergic dysfunction, fails to compensate the deficit induced by an intra-hippocampal injection of 8-OH-DPAT.98 WAY-100135 is also able to attenuate the detrimental effect of the blockade of NMDA receptors by MK-801 on working memory measured in rats in a delayed alternation task.132 We demonstrated that stimulation of hippocampal 5-HT1B receptors, by the specific 5-HT1B receptor agonist CP 93129, impairs the performance of rats trained in a radial arm maze using a procedure that makes it possible to dissociate working versus reference memory errors. This impairment affected the reference memory component of the task...

Brain Gut Peptides CCK Neuropeptide Y Galanin

Harro and Oreland51 studied the effect of CCK receptor agonists and antagonists on the ability to acquire an appetitively motivated task and to influence spatial memory. Studies have been carried out in which endogenous CCK was blocked in the posterior cingulate cortex of mice using a local injection of CCK-8 antiserum 74 and memory effects were tested using visual discrimination conditioning. Injection of CCK-8 antiserum 10-15 min before each session produced substantial learning impairment in the discrimination task. But when injections were stopped, animals began to learn the task normally, showing that the CCK antiserum effect was reversible. When the antiserum was administered at the same dose before a single test session 14 days after the end of the initial training, the retention was also affected. These results show that cingulate CCK can affect retrieval processes. Mice, partially trained to avoid foot shock in a T-maze, showed enhanced retention relative to vehicle-injected...

Interactions Between Cannabinoids And Dopamine At The Corticolimbic Structures

As mentioned in the preceding text, presynaptic CB1 receptors located in cortical and subcortical (limbic) structures might be involved in two well-known effects of exogenously added cannabinoids (1) cognitive effects and (2) reinforcing properties, which necessarily represent two key functions for the endocannabinoid signaling system in corticolimbic structures. Concerning the first of these effects, it is well established that CB1 receptors are moderately abundant in the cerebral cortex in particular, they are located in superficial and deep layers, presumably on GABAergic interneurons (Herkenham, Lynn, Little, et al., 1991 Mailleux and Vanderhaeghen, 1992 Breivogel and Childers, 1998 Tsou, Brown, et al., 1998). Endocannabinoids are also detected in the cerebral cortex (Bisogno et al., 1999). These data suggest a role for the endocannabinoid signaling system in the control of the sleep-waking cycle, performance of complex cognitive tasks, working memory, temporal organization of...

Olfactory and Gustatory Memory Paradigms

There are various behavioural models to assess olfactory memory, for example using a social recognition task. Adult animals meet a juvenile conspecific and explore him her via anogenital sniffing for say 5 mins. Reexposure to the same (familiar) juvenile after minutes to1 hour will lead to reduced anogenital sniffing reflecting recognition memory. If exposed to a different juvenile, however, anogenital sniffing will be high. Social recognition memory is affected by the CB1 receptor agonist WIN55,212-2 which reduced short-term memory (30 mins) in a dose-dependent manner without affecting anogenital exploration per se.93 This observation is in line with the original work by Terranova and coworkers99 who used subcutaneous injection of the CB1 receptor antagonist SR141716A at various time points after the first presentation of the juvenile. When injected immediately or 5 minutes post-presentation of the juvenile, SR141716A in doses of 0.1-3 mg kg enhanced social recognition memory tested...

Cannabinoids and anxiety

It seems clear that CBD decreased anxiety, which is often observed in people undergoing SPECT (single-photon emission computed tomography) or PET (positron emission tomography) scanning as measured by the VAMS. The brain area which showed increased activity in relation to placebo was the left parahippocampal gyrus. Deactivation of this area of the brain has been associated with panic attacks induced by lactate, anxiety induced by combat-related images and autobiographical memory scripts. It seems that anxiety is associated with reduced parahippocampal activity, consistent with the findings that CBD increases activity in this brain area. Because activity in the CBD condition decreased relative to the placebo, these data fit well since there are a lot of data linking amygdala activation in a large variety of anxiety states. Similarly, the hypothalamus is involved in various anxiety states imaging studies in particular have shown increases in hypothalamic activity in anxiety induced in...

Why Phosphorylation Might Be Critical for Memory Formation

Memory stages form in parallel or in sequence is yet to be fully resolved. That two or more biochemically- and temporally-distinct memory stages exist, however, is unquestioned.88 One or more labile short-term memory stages are assumed to precede the expression of permanent memories in all existing animal models, and these must be supported by the cellular processes underlying memory formation. A second assumption is that not all learned experiences are retained. Kety94 argued that it makes evolutionary sense to conserve memory capacity by consolidating only information that is 'biologically significant'. At some point between a learning experience and the relatively permanent changes presumed to underlie long-term memory, therefore, some mechanism must appraise the significance of each experience. The 'biological significance' of an experience depends at least partially on the level of arousal associated with it.127 In vertebrates, this may be mediated, at least partially, by the...

Human functional studies

Leon-Carrion (1990) compared 23 male chronic cannabis users (18-27 years) with 24 control subjects who had never smoked or used cannabis on the Wechsler Adult Intelligence Scale (Wechsler and Wechsler, 1981) and found heavy marijuana smokers showed significant impairment on 6 out of the 11 sub-scales of the WAIS. Schwartz (1991) studied six cannabis-dependent adolescents 48 h after hospitalization and after six weeks of monitored abstinence and compared them with two control groups. There was a significant impairment of test of visual and auditory memory, and the short-term memory impairment remained even after six weeks of abstinence. Deahl (1991) determined that available research provided sufficient evidence to conclude that people who smoke cannabis experience short-term memory deficits that persist after several weeks of abstinence. Mendhiratta et al. (1988) reported on a re-evaluation of heavy, long-term marijuana and hashish smokers and a control group after ten years. They...

Spatial Learning Water Maze

Training in an open water-filled tank containing a submerged platform is a popular learning paradigm tackling spatial and thus hippocampal-dependent memory.75 Animals learn to find the submerged platform in the opaque water in relation to distal cues and reduce their latency to swim and climb onto it over days. Despite its long tradition as a behavioural test, reports on the effects of cannabinoids are relatively recent. The initial report by Ferrari and colleagues28 revealed evidence for HU210-induced dose-dependent spatial acquisition deficits in rats for a reference memory paradigm in which the platform location was constant throughout training. A visible platform test showed no differences between the groups excluding sensory perception as a contributing factor. More recently, three reports extended this finding to A9THC in rats and mice14,73,101 and found that once spatial memory is acquired, consolidation and recall is not sensitive to cannabinoid treatment unless drug doses...

Signal Transduction Cascades

Hypoxia ischemic stroke dramatically impairs learning and memory.110 Long-term memory decline is evident even after brief episode of hypoxia ischemia.90 Therapeutic interventions designed to suppress disturbances of Ca2+ homeostasis induced by hypoxia ischemia must protect mitochondria from Ca2+ overload. At the same time, such intervention must prevent the ER from undergoing Ca2+ depletion.

Role of 5HT in Memory Global Strategies

Metabolism Neurotransmitter

Reducing central 5-HT synthesis through L-tryptophan restriction specifically impairs short-term and long-term memory performance in rats and humans.49,111 Depletion of 5-HT by using the tryptophan hydroxylase inhibitor, parachlorophenylalaline (PCPA), during synaptogenesis decreases synaptic density in the adult rat hippocampus, while inducing spatial learning deficits associated with failure to extinction and, consequently, relearning.87 In contrast, 5-HT depletion following 5,7-DHT lesioning has been found to facilitate acquisition and performance of various learning tasks in rats such as spatial discrimination,3 conditional visual discrimination (presumably by reducing proactive interference),131 and temporal discrimination under certain conditions such as when the task difficulty is increased.4 Fluoxetine, a SSRI, was found to weaken associative memory in the rat,97 but aged rats treated with a low dose of the 5-HT precursor (5-hydroxytryptophan, 5-HTP) improved their performance...

Receptors that Stimulate Adenylyl Cyclase

These basic modifications in neuronal excitability and or neurotransmitter release by 5-HT4 ligands in anatomical structures underlying learning and memory suggest an active role for this receptor in these functions. RS67333, a selective 5-HT4 agonist, prevents the performance deficit induced in rats by atropine in the Morris water maze, an effect reversed by the selective 5-HT4 antagonist RS67532.46 RS17017, another 5-HT4 agonist, enhances dose- and delay-dependently delayed-matching-to-sample performance in aged and young monkeys.126 Even if the 5-HT4 receptors do not seem to be tonically activated, the preacquisition administration of various 5-HT4 agonists generally improves memory in rats in the Morris water maze,46 in a social olfactory recognition task assessing working memory,74 or in an olfactory association learning, assessing long-term memory,83 whereas the post-training administration impairs consolidation in an autoshaping task in rats.88 However, post-training...

Protein Synthesis II New Proteins

The role of protein synthesis in long-term memory formation is still an area of intense scientific interest, which encompasses the study of mechanisms involved in gene expression and molecular mechanisms underlying synaptic plasticity. A number of low molecular weight compounds have been used to inhibit or enhance this fundamental cellular process. The pivotal role of protein synthesis in long-term memory formation suggest yet again that an understanding of how protein synthesis can be activated and regulated by events that ultimately lead to memory consolidation can lead to better understanding of the processes that keep our memories alive. A reasonable test for the hypothesis that new proteins are necessary for long term memory was to substantially prevent the expression of new proteins using protein synthesis inhibitors. A vast literature has developed using different drugs and antibiotics that inhibit protein synthesis. Early studies10,11,17 showed that actinomycin D, an...

Protein Synthesis I Pharmacology

The formation of long-lasting memory traces depends on the de novo synthesis of proteins. For more than 30 years substantial experimental evidence has been collected in species ranging from insects to mammals, in support of this hypothesis. A pharmacological approach to investigate the dependence of long-term memory formation on de novo protein synthesis is to administer drugs that prevent protein synthesis on the transcriptional or translational level. When injected during or after learning, these drugs block the development of long-term memory while leaving short-term memory unaffected. Recent research investigating the time course of protein synthesis following learning revealed the existence of two or probably more distinct time windows during which new proteins are synthesized in order to form an enduring memory trace. Another current topic addresses the question where in the neuron de novo protein synthesis takes place. Whereas a large part of the new proteins are synthesized in...

Protein Phosphatases in Rodent Learning and Memory

Pharmacological studies examining phosphatase involvement in memory formation in rodents have emerged only recently. One of these found that rats infused with OA for several weeks developed learning difficulties.4 The rats also demonstrated gross morphological changes, however, making it difficult to determine whether phosphatase inhibition was responsible for the learning deficits or whether these deficits may have reflected a secondary problem.136 In another study, microinjection of OA into the dorsal hippocampus was found to impair spatial reference and working memory one day later in rats. The impairment was reported to be transient, having disappeared by the following day.71 Chronic systemic administration of CyA at a concentration used therapeutically has been reported not to impair retention of information in rats.21 Indeed, FK506 was able to ameliorate a discrimination learning impairment induced by chronic cerebral hypoperfusion in rats,188 probably due to its well described...

Posterior Pituitary Peptides Vasopressin Oxytocin

The capacity of male rats to remember familiar conspecifics is called social recognition. It is a form of short-term memory. It measures the amount of time an adult male rat spends to investigates a juvenile. Recognition lasts 30 min and has disappeared after 120 min. Social recognition is also facilitated by vasopressin and attenuated by oxytocin.97 However, low doses of oxytocin microinjected into the preoptic area facilitates social recognition.9 Dluzen et al35 infused vasopressin and oxytocin bilaterally into the olfactory bulb in male rats and found that both peptides preserved recognition at 120 min. Antagonists of the two neuropeptides had no Ponomareva et al95 reported studies on the effects of intranasal administration of a new analog of arginine-vasopressin fragment AVP-(6-9), i.e., D-MPRG, on the learning ability of rats with positive and negative reinforcement. The peptide improved learning, i.e., accelerated the acquisition of a conditioned active avoidance behavior both...

Memory Studies with Adrenoceptor Agonists and Antagonists in Rats

In the past, studies on the involvement of adrenoceptors in memory formation in rats has focussed on identifying specific brain areas activated by systemically administered agonists and antagonist (Table 2). The search for memory functions related to the release of noradrenaline has concentrated on the amygdala (in particular the baso-lateral amygdala), prefrontal cortex, olfactory cortex and locus coeruleus. There has been very little work involving pharmacological intervention using adrenoceptor agonists and antagonists in the hippocampus. Izquierdo and coworkers37 have shown differential effects on short- and long-term memory with localized injections of noradrenaline.

Memory Studies with Adrenoceptor Agonists and Antagonists in Chicks

The memory time course which results from training with concentrated anthranilate on the bead reveals a model of memory where three stages are delineated by two periods (15 and 55 minutes after training) where the chicks appear to forget (Fig. 4). These two times correspond to the times for short-term, intermediate and long-term memory that have been defined on the basis of susceptibility to different classes of pharmacological drugs.26,30 These drugs inhibit memory when injected at particular times up to 30 minutes after training and inhibitors for each memory stage have characteristic time windows during which they have to be injected in order to inhibit memory.26,30 The determination of these times is also important for establishment of the roles of adrenoceptor subtypes in memory (see below, Table 3). ARs and the highest doses of noradrenaline inhibit memory via a1-ARs. Pre-administration of the a2-AR antagonist yohimbine did not affect the response to noradrenaline injected into...

Kinases and Phosphatases in Chick Memory Formation

Preliminary studies measuring activity levels of the various kinases and changes in substrate phosphorylation1,226 are generally consistent with the behavioural data. Importantly, however, these studies indicate that periods of kinase activity may be transient, suggesting that dephos-phorylation may also take place following a learning experience. It has also been found that the effects of PKC inhibition and activation are dependent on the level of reinforcement associated with the task.228 Pharmacological activation of PKC following weakly-reinforced training facilitates long term memory formation. Conversely, activation of PKC following

Joyce Besheer and Rick A Bevins Abstract

The nicotinic cholinergic system has been widely implicated in mediating learning and or memory processes in human and nonhuman animals. This chapter highlights various areas of basic research in which stimulation or blockade of nicotinic acetylcholine receptors (nAChRs) has been shown to affect an animal's performance in a variety of tasks thought to measure learning and memory. For example, under certain conditions, stimulation of nAChRs by nicotine (or other nAChRs agonists) can enhance working memory of primates as measured in a delayed matching-to-sample task. Attentional processes are also improved in rats as indexed by a five-choice serial reaction time task. Further, recent research suggests that stimulation of nAChRs by nicotine likely enhances the incentive salience of stimuli. We elaborate on a model by which this enhancement might occur and suggest that the role of this incentive mechanism in relation to learning and memory processes requires more empirical attention....

Jan PC de Bruin Abstract

Since the discovery that dopamine occurs in the cerebral cortex and functions as a transmitter a large number of studies has been conducted to examine its precise functions. It was found that administering dopaminergic drugs, either stimulating or inhibiting dopamine receptors, affected various modes of behaviour, including locomotor activity, eating and drinking, reward-related processes, and cognition. This chapter is especially concerned with the role of dopamine receptors in cognitive processes. It focuses on the mesocortical dopaminergic system, which, along with some other cortical areas, innervates the prefrontal cortex (PFC). This system is particularly sensitive to stressful stimuli, which, even when of small magnitude, leads to an elevation of prefrontal dopamine levels. Manipulations of this system have been shown to greatly affect behavioural functions, which depend on the integrity of the prefrontal cortex, such as working memory, attention and behavioural flexibility. To...

Intracerebral Infusion of Dopaminergic Drugs and Cognitive Processes

We will first review studies using local administration of dopaminergic drugs affecting D1 and D2 receptors and examining different cognitive tasks for working memory, attention, and behavioural flexibility. This experimental approach directly targets the prefrontal DA receptors and is expected to further support the indirect evidence provided by the studies reviewed above. The hallmark publication of research in this field was the study of Sawaguchi and Goldman-Rakic.53 Using a delay response task they examined behavioural changes resulting from local infusions of dopaminergic drugs in the dorsolateral aspect of the PFC in rhesus monkeys. Infusions of a D1 receptor antagonist (SCH2390) resulted in a decreased performance of this working memory task. The impairment was both dose-dependent and delay-dependent, indicating that it was truly working memory that was affected. It is also important to note that performance of a control task, requiring similar sensory and motor functions, was...

Hippocampal Involvement in Learning

In the early 1950s, numerous patients with intractable epileptic seizures underwent experimental surgeries involving removal of one or both temporal lobes. The surgeries appeared at first glance to be successful, as removal had the desired beneficial effect of ameliorating the seizures. However, in patients who had unknown temporal lesions in the opposite brain hemisphere or who underwent bilateral temporal ablations, the surgery had tragic results. One such patient, H.M., displayed severe anterograde amnesia following his surgery.87 Although memories formed prior to the surgery were relatively intact, H.M. seemed incapable of forming new long-term memories. For example, if given a three-digit number to memorize, H.M. could remember the number as long as he was able to continuously rehearse. If distracted even momentarily, H.M. would lose not only the memory of the number but also the memory of having been given the task in the first place. Thus, for H.M., the impairment was somewhere...

GABAergic Drugs and Memory Formation Administrations into Brain Structures

In a study carried out with rats tested in a one-trial step-through inhibitory avoidance task, immediate bilateral intra-amygdala administrations of baclofen impaired retention performance on a 48 h retention test (Fig. 3).23 Further, bicuculline methiodide (BMI) improved, while muscimol impaired retention (48 h later) in rats tested in a one-trial step-through inhibitory avoidance task and injected into the amygdala with the drugs immediately after training. In particular, the memory enhancing effect of BMI was produced by a dose lower than that necessary to induce convulsions. In a further series of experiments of this study posttraining injections of BMI into the caudate-putamen, a structure which is dorsal to the amygdala, did not affect retention (Figs. 4 and 5). 5 In another study84 the effects of intra-amygdala infusions of muscimol prior to retention testing was examined. Two sets of experiments were carried out. In the first set, rats were trained in a one-trial step-through...

Functional Studies Using a Central Approach

Studies using systemic administration of dopaminergic drugs and examining concomitant behavioural alterations do not directly reveal which brain areas are important for the performance of tasks under investigation. However, sometimes deductions can be made. When the task is sensitive for damage of a particular brain area, and when performance is affected by selective dopaminergic drugs, it can be assumed that the drugs exert their effect in that brain area. This can be exemplified by the study of Packard and White48 where the beneficial effects of a D2 receptor agonist (LY 171555) on a radial arm maze task were ascribed to the stimulation of D2 receptors in hippocampus and or nucleus caudatus. Similarly, the effects of selective D1 receptor agonists antagonists on working memory (reviewed above) were assumed to be due to D1 receptor stimulation inhibition in the frontal cortex. However, there are other techniques, which may provide such data in a more direct way. The oldest one is...

Dopaminergic Depletions and Cognitive Impairments

Of Brozoski et al13 already referred to in the Introduction, is an example of that approach. An example of studies in rodents using this methodology is the one of Bubser and Schmidt14 also targeting the dopaminergic innervation of the frontal cortex. They found a decreased performance in a spatial delayed alternation task, a working memory task known to depend on the integrity of the PFC. They also described an increased locomotion in their rats with prefrontal DA depletion. This is possibly due to an increased DA receptor activation in the ventral stria-tum (nucleus accumbens). In one of our own studies,58 we have also used the technique of reducing the dopaminergic innervation of the PFC. In this study lesions were made in the ventral tegmental area, the site of origin of the dopaminergic cells projecting to the PFC. We found a reduced level of DA in the medial PFC along with an impaired performance of a working memory task, spatial delayed alternation. Thus, our findings are...

Delayed MatchtoPosition

Several studies have tested for short-term memory in delayed-match-to-position (DMTP) or delayed-match-to-sample (DMTS) tasks. They are usually performed in a conditioning chamber and animals learn to press a lever during the sample phase and press the same (match) or opposite (nonmatch) lever during the choice phase. These tasks have a spatial component (right or left). In addition, task difficulty can be modified by increasing the delay between the sample and the choice phase with rats coming down to chance levels at delays of about 30-40 seconds.16 The group of Deadwyler has extensively used this task and determined a) the hippocampal involvement during performance,38 and b) the electrophysiological activity of CA3 and CA1 ensembles of neurones during the different phases of the task 6'33'37'39 using multielectrode recording techniques. In brief, principle neurones distinguish between the sample, delay and match phase. In a series of elegant studies, this group and others have...

DA Receptors and Eating and Drinking

Receptor activation in the PFC with the performance of working memory (e.g., Desimone,23 see below). In later studies, when more subtype-selective dopaminergic drugs were available, a distinction between D1 and D2 receptors was made. Clifton and co-workers17,18 found that especially D2 receptors are involved in food intake, whereas D1 receptors are of greater importance in controlling water intake.

DA Receptors and Cognition

When discussing DA receptors and locomotor activity we already pointed at the role of DA receptors in cognitive performance. This subject has been intensively studied by Goldman-Rakic, Arnsten, and co-workers in the nineties, using both monkeys and rats as experimental subjects. In a study with rhesus monkeys, Arnsten et al5 have provided compelling evidence that cognitive performance depends on DA D1 receptor mechanisms. In this study both young and aged monkeys were used. In aged primates there is a marked degeneration of the mesocortical dopaminergic system, with a loss of DA in the PFC. Other neurotransmitter systems in this brain area are less affected. Using a working memory task with delayed responding known to be sensitive to prefrontal damage, they found that task performance in young monkeys was impaired following administration of a D1 receptor antagonist (SCH 23390). In aged monkeys, however, this drug had no effect on task performance. By contrast, the D1 receptor agonist...

Cognitive Processes Associated with Changes in Cholinergic Activity

The first exposure to a novel environment causes pronounced behavioral activation.4,32 Giovannini et al65 demonstrated that when the rats are moved from the home cage to a novel environment ACh release from the frontal cortex increases during the exploratory activity. Conversely, if the rat is left in the novel environment, exploratory activity and ACh release decrease, presumably as a consequence of habituation. Explorations render the environment familiar33,67,187 since its features have been memorized. Behavioral habituation, which is usually demonstrated by a decrease in exploratory behavior, provides one of the most elementary forms of learning, both in animals and humans.

Cognitive Alterations Induced by the Blockade of Muscarinic Receptors

The nonselective muscarinic antagonist scopolamine has been extensively used to study the cognitive alterations induced by the blockade of muscarinic receptors.112 The interpretation of the pharmacological data is not straightforward, as scopolamine blocks postsynaptic receptors as well as presynaptic autoreceptors, this latter effect being responsible for an increase in ACh.197 Scopolamine administered to human subjects impairs rapid information processing209 and encoding of new memories in humans, primates and rodents (for review see ref. 82). Furthermore, scopolamine impairs the retention of contextual fear conditioning when administered immediately before or immediately post training,164 as well as spatial learning when administered before training in the spatial version of the Morris water maze.211 Scopolamine seems to be less disruptive to long term memory storage than to short term memory,12'68'146 indicating that once information has been consolidated it is no longer...

Cognitive Alteration Induced by Lesions in the Cholinergic Pathways

Destruction of the septo-hippocampal projections, either by kainate or ibotenate, impairs choice accuracy in experimental procedures implying short-term memory57 and transection at the level of the fimbria-fornix produce deficits in a T-maze performance.154 According to Casamenti31 the destruction of the NB obtained by bilateral injection of ibotenic acid results in a complete impairment of passive avoidance conditioned responses lasting at least 6 months. It has been demonstrated that quisqualic acid lesions of the nucleus basalis disrupts working memory evaluated by the object recognition test.11 working Memory, Short-term memory Working memory Working memory task190 when the toxin was injected into the NB or MS, respectively, and deficit in the acquisition of a working memory task14 when injected into either or both structures. Intraparenchymal injections of 192IgG-saporin have also been used to study the effects of basal forebrain cholinergic lesions on attentional processing....

CNS Distribution of the Muscarinic Receptors

Investigations on the physiological role of the various mAChR subtypes are hampered by the lack of selective agonists or antagonists for the specific receptor subtypes. Over the last few years several knockout mice strains have been developed for the M1,7 M2,69 M3119 and M4 receptors.70 The use of knockout animals might help to elucidate the physiological functions and pathophysiological implications of each receptor subtype. From these studies it appears that mAChR subtypes are involved in different physiological functions in the CNS, the M2 receptor being involved in movement, temperature control and nociception,69 the M3 in facilitation of food intake,220 the M4 in locomotor activity,70 and the M5 in water intake, and rewarding brain stimulation.221 Yamada and coworkers219 demonstrated that in M5 receptor knockout mice ACh looses its ability to dilate cerebral arteries and arterioles. Studies on M1 receptor knockout mice have given contradictory results concerning their role in...

Cell Adhesion Molecules

An important problem in the neurobiology of memory is whether cellular mechanisms of learning and memory include the formation of new synapses or the remodelling of existing ones. To elucidate this problem, numerous studies have examined alterations in the number and structure of hippocampal dendritic spines and synapses (see Geinisman et al in this book). This brain region, along with associated cortical structures in the temporal lobe, has been implicated in holding and processing information destined for consolidation as long term memory within the neocortex.2 Moreover, this consolidation process has been demonstrated to involve a molecular cascade of events within the medial temporal lobe in which enhanced neural activity activates gene transcription, protein synthesis and synaptic reorganisation.5'37'70'72 Activity-dependent synapse selection is attractive in its simplicity and most likely will provide a basis to understand neuroplastic events subservient to behavioural...

Cannabinoid Receptors Modulate Memory Formation

Most of the animal research summarised below has been guided by work on human subjects, for which disruption of short-term memory is a widely acknowledged effect of marijuana or A9THC.11-13'24,29'72,95 Direct effects on memory storage, however, have not been found.3'24 Interestingly, marijuana increased cerebral blood flow predominantly in paralimbic regions of the frontal lobes and the cerebellum, but reduced blood flow in the temporal lobe. 2 Such hypoactivity may be the neural basis of cognitive alterations. It is also in line with observations that marijuana addicts have reduced amplitudes in P300, an event related potential reflecting attentional resource allocation and active working memory54 and that monkeys treated with A9THC chronically have predominantly slow wave EEGs (1-2Hz) in hippocampus, amygdala and septum.96

CaMkiv A New and Important Player in the Plasticity Team

Pendent kinase kinase or CaMKK) and to occur it needs binding of Ca2+ CaM to both CaMKK and its substrates.92 CaMKI is enriched in neuronal processes and synapses60 but, in contrast, CaMKIV and the P isoform of CaMKK are enriched in the nucleus.44,92 This subcellular distribution suggests a role for CaMKIV in the onset of nuclear responses to synaptic stimulation and may be related with the observed effect of CaMKIV-signalling inhibition in the protein synthesis-dependent phase of different plastic events. It has been early shown that CaMKIV regulates CREB-dependent gene expression66 and that it is able to phosphorylate CREB and the transcriptional coactivator CBP.9,17 KCl-mediated depolarisation and rNMDA stimulation increase CaMKIV activity in hippocampal neurons48 and disruption of CaMKIV expression blocks KCl-induced CREB phosphorylation.9 CaMKIV mutant mice present a decrease in both basal and experimentally-induced levels of phosphoCREB together with impaired LTP38 Recently,...

CaMKII Synaptic Plasticity and Memory Processing

In the rat, one-trial step-down avoidance learning is associated with a rapid and specific increase in hippocampal CaMKII activity14 and, pharmacological evidences indicate that its participation is restricted to a narrow posttraining time window and involved, mainly, with events related with the consolidation of long-term memories. For long-term retention of the avoidance response measured 24 hs posttraining, the intrahippocampal infusion of a CaMKII blocker causes full retrograde amnesia only when given immediately after the acquisition session 30 min posttraining, CaMKII inhibition produces just partial amnesia and, interestingly, no effect at all in long term memory formation is observed when the drug is administered 2 or 3 hrs posttraining1 5 or when short term avoidance memory is measured 90-120 min after training.42 Passive avoidance,122 but not imprinting,93 also induces CaMKII phosphorylation in the chick intermediate medial hyperstriatum ventrale (IMHV) and lobus...

Ligand Gated Ion Channel

Initial research on the role played by 5-HT in learning and memory started by demonstrating that 5-HT3 receptor antagonists are able to improve learning and memory or to antagonize the effects of anticholinergic or age-induced memory decline in rodents and primates,10 which is a more recent discovery for other types or subtypes of 5-HT receptors. The beneficial effect of 5-HT3 antagonists currently receives additional support. Thus, while mCPBG, a 5-HT3 agonist, impairs retention of an associative learning task in rats, ondansetron and tropisetron, 5-HT3 antagonists, improve it.63 Ondansetron prevents scopolamine-induced impairment of short-term memory retrieval in mice,114 as well as intra-hippocampal scopolamine induced impairment in rat spatial learning in a water maze.29 Y-25130, another 5-HT3 antagonist, has a similar compensatory effect on working memory impairment due to cholinergic blockade in rats, but is ineffective to compensate memory impairment due to blockade of...

Anti Idiotype Antibodies

The immune system discriminates between self and nonself (i.e., foreign) antigen. The foreign antigen can stimulate an immune response, and the immune system sets in motion a steady-state memory lymphocyte which, upon reinfection with the same or closely related antigen, is able to respond with a vigorous immune response. If the foreign antigen is a complementary structure, then one might influence the immune system to recognize the mirror image of the complementary structure. Thus, immunization of an animal with a monoclonal antibody that recognizes the transition state for detoxication of a drug of abuse should elicit an immune response and produce antibodies that resemble the structure of the drug of abuse. The second antibody, the anti-idiotype antibody, thus mimics the transition state for detoxication. Injection of this second antibody into an animal could create a relatively long-term memory effect to give protection against the drug of abuse the third antibody produced could...

Understanding The Tools

The main physical danger with psychedelics is with those that are MAO inhibitors and with combinations. Two psychedelics discussed in this book are MAO inhibitors 5-MeO-DMT and the Harmala alkaloids. Many prescription anti-depressant drugs are also MAO inhibitors. MAO (Mono-Amine-Oxidase) is an enzyme in the body which breaks down certain foods and chemicals. If one has these foods or chemicals in their system while taking an MAO inhibitor they will not be broken down, which can result in discomfort, illness, or even death. Following this section is a list of items not to be taken with MAO inhibitors. Prior to taking an MAO inhibitor I review this list and do a double check on what's in my system. I've also found it useful to memorize this list of items so that I don't eat any foods that will make me sick while using MAO inhibitors.

The Health Effects Of Chronic Cannabis

Cognitive impairment, particularly in short-term memory, is often reported by cannabis-dependent persons seeking help to stop using cannabis (Solowij, 1998). Controlled studies have not found that long-term use produces severe impairment of cognitive function (Solowij, 1998). Lyketsos et al. (1999) assessed cognitive decline on the Mini Mental State Examination (MMSE) in 1318 adults over 11.5 years. They found no relationship between cannabis use and decline in MMSE score, indicating that cannabis use did not produce gross cognitive impairment (Solowij, 1998). This study does not exclude the possibility of more subtle cognitive impairment, because the MMSE is a screening test that is not sensitive to small changes in cognitive functions, and in this study heavy cannabis users included anyone who ever reported smoking daily for more than 2 weeks.

Classical Herbal Drugs of Abuse 1931 Cannabis and Tetrahydrocannabinol

THC increases the heart rate, blood pressure, and body temperature. More importantly, smoking THC produces a range of cognitive and psychomotor effects associated with a transient euphoric effect that is usually perceived as a high. Short term memory loss can occur particularly with repeated use.

Knowledge

We all know we have a brain, encased in a skull. Inside this brain there is some strange looking matter, which, whilst invisible to the naked eye, and having no visible moving parts, is doing some pretty amazing stuff. This amazing stuff also has the ability to store what we perceive, through seeing, hearing, feeling, touching, or smelling. This goes into the mysterious box in your head and is stored somehow (sorry I'm not a scientist ) into short and long term memory available for recall at some future time.

Cognition

The amnestic effects of benzodiazepines are pervasive and appear to derive from disruption of the consolidation of short-term into long-term memory (79). Amnesia appears to underlie the tendency of regular hypnotic users to overestimate their time asleep, because they simply forget the wakeful intervals (80) in contrast, the same patients underestimate their time spent asleep when drug-free. This amnestic property (SEDA-17, 42) (SEDA-19, 33) has been used to advantage in minor surgery, particularly with midazolam and other short-acting compounds (although male doctors and dentists are advised to have a chaperone present when performing benzodiazepine-assisted procedures with female patients). However, unwanted amnesia can occur, particularly with triazolam, when used as a hypnotic or as an aid for travelers (81,82). The combination of a short halflife and high potency, especially when it was used in the higher doses that were recommended when the drug was initially launched, makes...

Memory

Manipulation of nAChRs has been shown to affect performance in a variety of tasks that assess memory functioning. In nonhuman animals, a majority of this work has been conducted in tasks designed to assess working memory processes. Working memory is defined by Feldman et al34 as encoding of task-specific information over short periods of time (e.g., within a single trial or test session) (p. 272). The delayed matching-to-sample (DMTS) task is a commonly used preparation for assessing working memory. Briefly, in this task an animal is presented with a sample stimulus. Following a delay, the animal is presented with the sample stimulus and one or more novel stimuli. During this choice test, the animal is rewarded for choosing the sample stimulus. Thus, working memory processes are recruited to encode the information of the sample stimulus in order to make a correct response during the choice test. That is, working memory allows the animal to discriminate between the sample stimulus and...

Other Effects

Additional functional effects of nAChRs include alterations in pain, anxiety, appetite, depression, epilepsy, and motoric abilities. Although a comprehensive discussion of these effects is beyond the scope of the present review, their potential influence (direct or indirect) on learning and memory deserves mention. We will use as an example the locomotor effects of centrally located nAChRs. Most of the nonhuman animal research investigating attention, reward, or working memory include controls to assess whether the motoric effects of the nAChR ligand of interest could account for group differences. Such controls are important in that nAChR agonists can alter general locomotor activity.8,42,61,68,92 Whether the change is locomotor suppression or stimulation depends on such factors as selectivity of ligand, dose, pretreatment or preexposure history, rodent strain, and environmental familiarity. Accordingly, if one is investigating the memory enhancing effects of, say, chronic nicotine,...

Acknowledgements

D., Andrusiak, E., Tran, A., Bowers, M. B. Jr. and Roth, R. H. (1997) Delta 9-tetrahydrocannabinol increases prefrontal cortical catecholaminergic utilization and impairs spatial working memory in the rat blockade of dopaminergic effects with HA966, Neuropsychopharmacology 16 426-432.

W Health

Although a consensus has not been reached, many studies have presented evidence suggesting intoxication-induced impairment even in long-term regular cannabis users. There is, however, general consensus on the acute effects. During acute intoxication, cannabis disrupts vigilance, ability to perform mental tasks, explicit and working memory, and one's ability to correctly estimate intervals of either time or space. Negative reactions such as panic, random disconnected thoughts, hallucinations, delusions and other disturbing perceptual changes can also occur in some individuals (24). Although occasionally appearing at typical recreational doses, such responses occur more frequently with does significantly larger than typical for the individual in question (Interestingly, the WHO has suggested that at least synthetic THC be placed on Schedule IV of the United Nations Convention on Psychotropic Drugs, the lowest and least restrictive of this scheduling system (24).). It seems that, with...

The Hoasca Project

Diagnostic and life-story interviews identified appreciable past psychiatric and substance abuse histories in the UDV subjects prior to their entry into the ayahuasca church, including 73 percent with histories of significant alcohol use, 33 percent with alcohol binging associated with violent behavior, 27 percent with stimulant abuse, and 53 percent with tobacco dependence. For all of these subjects, however, past psycho-pathology had resolved following initiation and regular attendance at ayahuasca ceremonies. Personality testing identified significant differences between the ayahuasca-using and nonusing groups. These included measures of novelty seeking, with UDV members described as being more reflective, rigid, loyal, stoic, slow-tempered, frugal, orderly, and persistent, and also scoring higher on measures of social desirability and emotional maturity than controls. Ayahuasca-using subjects were also distinguished from controls on the harm avoidance domain as being more...

Conclusion

Rigorous research provide evidence for impaired learning, organization and integration of complex information in tasks involving various mechanisms of attention, memory processes and executive function. It is not clear to what extent the alterations in brain function and cognitive impairments as detected in laboratory testing might impact upon daily life, although users themselves complain of problems with memory, concentration, loss of motivation, paranoia, depression, dependence and lethargy (Reilly et al., 1998 Solowij, 1998). Schwenk (1998) has argued that there is no clear causal relationship between marijuana use and job performance. The nature of the cognitive deficits as assessed by psychological testing suggests that long-term users would perform reasonably well in routine tasks of everyday life, although they may be more distractible and short-term memory may be compromised. Difficulties are likely to be encountered in performing complex tasks that are novel or that cannot...

Anxiolytics

SL65.1498 The pyrido-indole-4-carboxamide derivative SL65.1498 shows higher affinity for a1, a2 and a3 GABAA receptors compared to a5 receptors. In addition, it acts as a full agonist at a2 and a3 receptors but as partial agonist at a1 GABAA receptors. In line with its selectivity for the activation of a2 and a3 receptors, the compound showed potent anxiolytic action in animal models (punished lever pressing, punished drinking, elevated plus maze, light dark test) but did not impair motor coordination (e.g. rotarod) or working memory (Morris water maze) (Scatton et al. 2000).

Dreamformation

It has been speculated that the reason we are unable to retain dream experience is because the normal neuronal mechanisms which underlie long-term memory processes are shut off during the dream state. This, however, is not the case with 'waking' psilocybinetic dreams visions, since the neuronal systems which facilitate long-term memory are still operative. Psilocybin is therefore able, perhaps, to by-pass those brain mechanisms which normally serve to stop us consciously attending to information arising from the creative depths of the psyche.

Spatial Learning 411

Animals learn to find the submerged platform in opaque water in relation to distal cues a progressive reduction of the latency to swim to and climb onto the platform is an index for learning. If the platform is kept in the same place, this is a reference memory task while changing the platform location to a new position every day reflects a working memory paradigm. When exposed to a working memory paradigm, in which the location of the platform was changed on a daily basis, A9THC-treated mice were impaired in finding the platform despite extensive pre-training over weeks. Consequently, Varvel and co-workers (2001 Lichtman et al. 2002) claimed that spatial working memory in mice is more sensitive to cannabinoid treatment. Despite extensive pre-training of the mice to the working memory task, animals were unable to remember the new platform location when under A9THC. However, mice in the reference memory paradigm were also extensively pre-trained, and...

Cognition and memory

In humans, acute and chronic use of marijuana induces severe disruption of immediate recall, short-term memory and memory retrieval (see Davies et al., 2002). The cellular and molecular mechanisms underlying learning and memory deficits produced by cannabinoids, and the role of endocannabinoids in such mechanisms, have been investigated in a number of studies using in vivo and in vitro systems. Behavioral data support the hypothesis that the EPCS plays a role in memory processes and suggest that a disruption of normal hippocampal function contributes to learning and memory impairments produced by cannabinoids (Sullivan, 2000 Davies et al., 2002). In vitro experiments indicated that cannabinoids and endocannabinoids produce persistent changes in memory-related neuronal activity (Gerdeman and Lovinger, 2003). The dense localization of CB1 receptors in the hippocampus and amygdala, which play an important role in learning and memory, may represent the anatomical substrate for...

Radial Arm Maze

Nevertheless, numerous reports suggest that cannabinoids impair performance in the 8-arm radial maze, especially when short-term memory is tested. This has been originally reported in chronic experiments with A9THC administered for 3 or 6 months,97 and corroborated later for acute infusions of A9THC,42,58,60,73,74,77 acute systemic administration of the full synthetic CB1 receptor agonists WIN55,212-2 and CP55,940 (see ref. 60) or local infusion of CP55,940 directly into the hippocampus.60 In most cases, animals were trained to criterion performance in a working memory task with all 8 arms baited. Systemic treatment with cannabinoids increased the number of working memory errors (reentries of previously baited arms) (see refs. 73,74,97) with low doses not affecting the amount of time required to complete the 4 visits.42 Short-term memory can be tested by introducing a short delay between visits to arms 1-4 and 5-8. Cannabinoids also disrupt performance after a 5s,74 30s,42 or 1h delay...

Avoidance Tasks

Similarly, an acquisition impairment was reported for rats tested in an active avoidance paradigm (Izquierdo and Nasello 1973). The weak CBi receptor ligand cannabidiol (3.5 mg kg) reduced conditioned responding, but was not effective when administered immediately post-training. This result is in agreement with more recent active avoidance training in CB1-null mutant mice, which showed increased conditioned responding consistent with memory enhancement (Martin et al. 2002). At odds with these results is the finding that rats chronically treated with A9 THC (20 mg kg) for 3 months and subsequently left untreated for 30 or 118 days before training in a shuttle box outperformed controls (Stiglick et al. 1984). Animals that had been exposed to A9THC attained asymptotic performance levels faster than controls. It remains to be shown whether this effect is mediated by the cannabi-noid system. An interesting comparison can be made with hippocampally lesioned animals. Such rats also show...

Ginkgo biloba

Memory retention in young and old rats 42 , and improve short-term memory in mice 43 . G. biloba attenuates delayed neuronal death in the CA1 of the hippocampus in Mongolian gerbils 44 and is also associated with reduced stroke infarct volume in mice subjected to 45 min of tMCAo 45 .

Relationships

So next time you think about diverting a river, blowing up your neighbour, destroying ancient forests, punching someone in the face you don't like, or getting angry at your partner for complaining about stomach cramps, remember everything is a part of you, and that the whole world is kept in balance by an invisible relationship and a mere 23.5 degrees of tilt. How can we think that we can keep going the way we are, without something in the relationship changing 23.5 degrees - the angle that keeps everything just so. That the summer comes every year and so does the winter that the cycle of life is maintained.

Isoflurane

The effects of the combination of midazolam and isoflur-ane on memory were studied in a randomized, doubleblind study in 28 volunteers (50). Midazolam 0.03 mg kg or 0.06 mg kg combined with isoflurane 0.2 almost completely abolished explicit and implicit memory, but there were more variable effects on the level of sedation. The duration of the deficit averaged 45 minutes. The study was remarkable for the very low doses required to abolish memory, owing to synergy of the combination of midazolam and isoflurane and abolition of memory at subhypnotic doses with this combination. However, the subjects did not undergo surgery, so caution must be exercised in extrapolating the result to surgical patients, because painful stimuli increase the dosage required to abolish memory.

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