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The effect of dipeptides AspPro and AspSer and of their composing amino acids (asparagine acid--Asp, proline--Pro, serin--Ser) on the proliferative activity in the explants of cortex and subcortical structures of the rat brain and on the functional activity of CNS of the honeybee was studied. The square index defined as a proportion of the whole explant square to the square of its central zone was determined. The number of bees responded with the conditional reaction (proboscis extension in the direction to aromatized solution) after 1 min (short-term memory) and 180 min (long-term memory) was detected after single learning procedure. Both dipeptides, as well as the asparagine acid, stimulated an increase of the growth zone of the subcortical structure explants in rats and of the number of honeybees with retention of conditional reaction in the short-term/long-term memory independently of the effect of the second member of the dipeptide. The unidirectionality of the effect suggests the existence of common mechanisms of reception and signal transduction established during evolution that require the further study.

The aim of this work was to study the delayed effects of chronic neonatal administration of the selective serotonin reuptake inhibitor fluvoxamine (FA) to white rat pups and to estimate the possibility to correct these effects by treatment with semax. Fluvoxamine was injected intraperitoneally at a dose of 10 mg/kg from postnatal days 1 to 14, and semax was injected intranasally at a dose of 0.05 mg/kg from postnatal days 15 to 28. It was shown that neonatal FA administration produced a significant delay in animal somatic growth. A loss in body weight was detected both during FA administration and 4-6 weeks after the last injection. Furthermore, FA administration increased the anxiety level and disturbed the learning ability of animals. The negative consequences of neonatal FA administration were largely compensated by Semax.

Memory consolidation is a term used to describe the process of memory stabilization from labile, easily disrupted state into disruption-resistant long-term form. Protein synthesis inhibitors injected before or immediately after learning episode, produce significant amnesia. However in a limited number of studies the possibility of memory recovery after such pharmacologically-produced amnesia was shown. The aim of present study was to investigate the possibility of memory recovery in single-session fear conditioning paradigm in mice. Mice were injected with protein synthesis inhibitor cycloheximide twenty minutes prior learning to induce amnesia. Twenty four hours after training mice were subjected to reminder shock, similar to one used during training. Amnestic animals have demonstrated complete recovery of cued fear memory to the level of normal animals when tested 24h after reminder presentation. Thus our data indicate that specific type of memory might be restored using nonspecific stimulus as a reminder. Possible mechanisms of memory reparation after PSI injection during learning are discussed.

The effect of dipeptidal neurotensine mimetic, N-caproyl-L-prolyl-L-tyrosine methyl ester (GZR-123, Dilept) and its main metabolite N-caproyl-L-prolyl-L-tyrosine (GZR-125) was evaluated at novel objects recognition test (NOR) in the male outbred rats. NOR was chosen from many cognitive test as those involving the selective action on the attention and episodic memory and considering as translational model for the study of cognition deficiency in schizophrenics. M-cholinoblocking agent scopolamine (0.2 mg/kg s.c.) was used as agent disturbing the performance of the test. Dilept (2 mg/kp i.p.) was shown to restore the NOR performance, disturbed by scopolamine. The same was true for GZR-125 (2 mg/kp i.p.), whose cholinopositive effect could contribute to the procognitive effect of the parent molecule.

In experiments on rats showed that intranasal administration of glutamate antibodies in a dose of 300 microg/kg after 1 h after bilateral injection of neurotoxic fragment of beta-amyloid protein (25-35)--Abeta(25-35)--into the Meynert nuclei restores learning ability in the test of passive avoidance on 3 and 14 days of the experiment. Antibodies to glutamate decrease significantly increasing caspase 3 activity, detected on Day 3 after injection of Abeta(25-35), in samples of the prefrontal cortex and hippocampus but not hypothalamus. Intranasal administration of gamma-globulin had no effect on the performance of violations of mnestic functions and caspase 3 activity.

Authors have studied the efficacy of adaptol and neyromidin in the combined treatment of patients with chronic cerebral circulation insufficiency and consequences of closed head injury using neurophysiological monitoring which included dynamic evaluation of central conductivity, neuropsychological tests and analysis of blood BDNF levels. Severe autonomic disorders, anxiety and low level of learning observed in all patients are correlated with neurophysiological (increased central conductivity time) and neurotrophic (decreased blood BDNF levels) profiles. These indicators may change throughout the treatment. The combination of adaptol and neyromidin enhanced greatly the efficacy of combined treatment. The received data allow recommending neurophysiological monitoring for treatment optimization of numerous neurological diseases that demand neuroplasticity stimulation.

The effects of repeated opilong injections in a dose of 50 microg/kg/day on subsequent learning of Wistar rats have been studied. The substance caused significant anxiolytic and analgesic effects, as the majority of animals could be learned (90% against 40% in control group) despite of painful stimulus preceding to education. Opilong in a small dose displaced a relation of excitatory-inhibit processes to significant prevalence of excitation although the substance was already absent in an organism for a long time. Raised peripheral sensitivity in all rats, provoked by opilong, correlated with CNS hyper excitability, expressed in stressful, neurotic psychoemotional reactions and in the form of active avoidance. The biochemical blood analysis in opilong-induced rats demonstrated the attributes of prethrombosis in the form of fibrinolysis depression and hypercoagulation. A view is expressed, that the neuromediator brain systems can be the basic point of opilong action, that are responsible for the excitatory-inhibit conditions of CNS functioning referred on maintenance of conditioned field stability.

In the presented review given literature and results of own studies of dynamics of electrical characteristics of neurons, which change are included in processes both an elaboration of learning, and retention of the long-term memory. Literary datas and our results allow to conclusion, that long-term retention of behavioural reactions during learning is accompanied not only by changing efficiency of synaptic transmission, as well as increasing of excitability of command neurons of the defensive reflex. This means, that in the process of learning are involved long-term changes of the characteristics a membrane of certain elements of neuronal network, dependent from the metabolism of the cells. see text). Thou phenomena possible mark as cellular (electrophysiological) correlates of long-term plastic modifications of the behaviour. The analyses of having results demonstrates an important role of membrane characteristics of neurons (their excitability) and parameters an synaptic transmission not only in initial stage of learning, as well as in long-term modifications of the behaviour (long-term memory).

The effects of original domestic derivatives of 3-oxypyridine and succinic acid (emoxipine, reamberin, and mexidol) on cellular composition of cortical and diencephalic structures in rat brain were studied in parallel with monitoring of behavioral, conditional learning, and metabolic disorders in acute phase of alloxan-induced diabetes in rats. The efficiency of 3-oxypyridine derivatives was compared to the results of alpha-lipoic acid administration. Single administration of emoxipine, reamberin, and mexidol in optimal doses prevented lipofuscin deposition in CA1 field neurocytes in hippocampus and/or increased the amount of terminally differentiated cells ofneuroectodermal lineage (oligodendrocytes, pyramid and basket cells) in this zone ofpaleocortex. Concurrently conditional learning capacity in morbid animals was restored. The cerebroprotective and nootropic effects of emoxipine and reamberin were associated with increased exploration motivation in the open field and were independent of their effects on carbohydrate and lipid metabolism dysfunction. On the contrary, the neuroprotective and nootropic effects of mexidol were associated with additional inhibition of morbid rat activity in the open field and a decrease in the level of circulating products of lipid peroxidation. It is established that 3-oxypyridine and succinic acid derivatives significantly exceed alpha-lipoic acid in terms of neuroprotective effects but exhibit significantly lower hypolipdemic activity in acute phase of alloxan diabetes.

Heptapeptide Semax (MEHFPGP) is the fragment of ACTH(4-10) analogue with prolonged neurotropic activity. The aim of the present work was to study the Semax effects on learning capability and pain sensitivity in white rats following intraperitoneal and intranasal administration in different doses. Semax nootropic effects were studied in the test of acquisition of passive avoidance task. Pain sensitivity was estimated in Randall-Selitto paw-withdrawal test. It was shown that Semax exerts nootropic and analgesic activities following intraperitoneal administration. Analysis of dependence of these effects on dose resulted in different dose-response curves. Following intranasal administration, Semax was more potent in learning improvement compared to intraperitoneal administration. The peptide failed to affect the animal pain sensitivity following intranasal administration as opposed to intraperitoneal administration. The data obtained suggest different mechanisms and brain structures involved in realization of the nootropic and analgesic effects of Semax.

This review considers data obtained during the entire research period of state-dependent learning. Understanding of this phenomenon has significantly evolved during the past decades, as a result of the increasing amount of facts revealed while studying state-dependent learning. Consequently, a situation has arisen where different papers may describe same phenomena using different terms. This does not promote understanding of the described phenomena. Therefore a need for a paper emerged, that would analyze the evolution of state-dependent learning and would offer terminology corresponding to all the data collected on the subject.

Recent literature on human cognitive activity enhancement is reviewed and summarized. Two classes of pharmacological approaches are picked out, i.e. modern aspects of traditional substance utilization and application of specially developed drugs. Among non-pharmacological approaches a number of psychological, physiological, behavioral and biophysical methods to improve human cognition, memory and learning are analyzed. The most attention is paid to non-drug approaches that utilize bioelectric processes of the individual including characteristics of its brain electrical activity--electroencephalogram (EEG) to enhance different aspects of cognitive functioning. Some promising lines of these investigations are delineated.

Intraperitoneal administration of afobazole in a dose of 0.1 mg/kg over 2 weeks after repeated modeling of intracerebral post-traumatic hematoma reduces animal mortality, decreases motor coordination disturbances, and improves learning and memory processes in rats.

The aim of the research was to examine possible role of exogenous phosphatidylserine in the modulation of the phospholipid turnover in the hippocampus and cognitive function of old rats. It has been determined that phosphatidylserine content in the hippocampus of the old rats intragastrically fed with lipids increased up to the level of phosphatidylserine in the brain of young animals. The exogenous phosphatidylserine had no effect on the phosphatidylethanolamine turnover and increase phosphatidylcholine synthesis in the hippocampus of old rats. Cognitive function of lipid-fed and control 24-month-old rats were studied with the aid of the active avoidance test in shuttle box. It has been determined that phosphatidylserine increased the number of active avoidances and decreased latency of active avoidance reaction in the learning session as compared with control rats.

The impact of long-term intake of drinking water containing the high level of chromium and benzene or their mixture on navigation learning and long-term spatial memory was studied in a Morris water maze. The chronic neurotoxic effect of benzene was characterized by worse long-term memory, which upon its exposure in combination with chromium remained unchanged and failed to block the realization of a positive effect of chromium on the mechanism of navigation learning.

The analysis of neurophysiological and neurotransmitter implementing of nervous processing: excitation, inhibition and disinhibition that were distinguished by Pavlov's school was fulfilled in the paper. The systematization of our data and one of literature permits to do the next conslucision. (I) The increasing of inhibitory hyperpolarization processes that become apparent in increasing of slow potential oscillations (SPO) and phasic neuronal activity (alternation of activation and inhibition of action potentials) determines the elaboration of internal inhibition. The basic neurotransmitter of hyperpolarization inhibition in the brain cortes is gamma-aminobutyric acid (GABA). (II) The reinforcement and, after a few combination with it, a conditional stimulus call the activation of electroencephalogram (EEG). On the background of activation EEG take place the transfer of neurons from chaotic or irregular group action potentials to the next forms activity: (1) the acceleration of action potentials, (2) tonic flows of impulses due to decreasing of inhibitory pauses and postinhibitory activation, in other words, disinhibition, (3) tonic inhibition of action potentials in brain cortex, (4) the most part of neurons of hippocampus and other structures of limbic system works in the rhythm theta--5-7 c/sec on the background of activation of EEG. (III) The glutamatergic neurotransmitter system plays the important role in the transmission of "modal-specific" influences of conditional and unconditional stimuli. The cholinergic and other neurotransmitter systems take part in the transmission of "modal-nonspecific" influences. (IV) The tonic inhibition that appears by EEG activation, it may be, plays the important role in realization of external inhibition. (V) Neurophysiological and neurotransmitter basis of behavioral disinhibition, presumably, can have several reasons: (1) a simple exceeding of excitatory influences over inhibitory one, (2) "the inhibition of inhibition", (3) "depolarization induced suppression of inhibition" (DSI).

The psychophysiological and morphofunctional effects of chronic administration of saline, which is commonly used as an active control, to Wistar rats were analyzed at different levels. The active control proved to be complicated by signs of stress manifested as increased corticosterone levels, changes in the homeostatic system, blood cytometric indices, morphofunctional states of the thymus and spleen, sharp suppression of the cognitive activity, and decrease in the motivational and locomotor activities. Pain expectation developed in animals after the second saline injection in the tail-flick test--pain sensitivity sharply increased in the session prior to the injection. These signs of stress should be taken into account for interpretation of the effects in drug tests.

The possibility of dissociated learning was investigated using drugs which act directly on GABAB receptors of the brain. The earlier proposed suggestion that the cholinergic system plays a key role in the mechanisms of dissociated learning was tested. It was shown in male Wistar rats that dissociated learning was possible with GABAergic drugs. The dissociated state was induced by injecting the animals with both GABA agonist Baclofen and GABA antagonist 5-aminovaleric acid. Thus, dissociated learning is possible with drugs which act on either cholinergic or GABAergic transmitter systems.

The delayed effect of food-derived opioid peptides (exorphins) after chronic administration on postnatal days 1-14 on the learning of albino rat pups has been studied. Heptapeptide YPFPGPI (beta-casomorphin-7), pentapeptide YPLDL (rubiscolin-5) and pentapeptide YPISL (exorphin C) improved the development of the conditioned foraging reflex in a complex maze. Hexapeptide PFPGPI lacking the N-terminal tyrosine proved inefficient. Only beta-casomorphin-7 had an effect (negative) on passive avoidance conditioning. The obtained data confirm that exorphins (particularly, milk-derived beta-casomorphins) can have significant and long-term effects on the environmental adaptation of young mammals.

Effects of repeated piracetam (PIR) injections in a dose of 40 and 250 mg/kg/day on the learning in Water rats were studied. It has been found that character of the effects depends on typological features of the animals. Rats with strong predominance of excitation (choleric type) showed low sensitivity to PIR. Small dose of PIR provoked clear negative effect in rats with relative balance of the basic nervous processes: excitation and inhibition (sanguine and phlegmatic types). Despite of expressed activation of associative process, it complicated integrative activity. Small dose of PIR showed anxiolytic and psycho-stimulant actions only in initially unlearned rats characterized by high level of fear. Large dose of PIR had negative influence on the learning process in all animals, irrespective of typological features. Thus, the results of this study allow to suppose that the individual sensitivity of an animal to action of a pharmacological medication is caused by morpho-functional and neurochemical intraspecific heterogeneity.

Daily introduction per os of the exogenous melanin in a doze of weight of 10 mg/kg pregnant female rats of line Wistar on a background continuous irradiations (dose rate of 2.6 mGy/h within 20 days of pregnancy) eliminated deficiency cognitive functions at posterity. On the basis of the received data it is concluded presence radioembryoprotective actions of melanin in the relation neuro embryotoxic effects of small dozes ionizing radiation. Taking into account small toxicity of melanin, the preparation can be perspective for practical application.

Influence of neurotoxic fragment of beta-amyloid peptide (25-35) on Helix lucorum behavioral plasticity (sensitization and food-aversion learning) was investigated. After beta-amyloid peptide (25-35) injection a significant reduction of behavioral long-term sensitization was observed. It was found, that beta-amyloid peptide (25-35) may interfere with associative learning and memory. Our results clearly demonstrate that beta-amyloid peptide (25-35) may play a significant role in behavioral plasticity by chronically eliminating certain underlying forms of synaptic plasticity.

With the Western-blot analysis, we studied the activation of MAP/ERK protein kinases (regulating genes expression by the phosphorylation of transcription factors (TF) CREB and ELK-1) in native Helix pomatia and in animals with disturbed abilities to form long-term conditioned avoidance reflexes. Different stages of this reflex formation were shown to be characterized by different levels of MAP/ERK kinases activation, the latter being different in CNS's regions (visceral complex of ganglia, cerebral and pedal ganglia) playing different roles in the reflex formation. The dynamics of activation was wave-shaped with peaks at 10 min and 4 h. The treatment of snails with the neurotoxin 5,7-DHT (causing disfunction of serotoninergic terminals and reducing capability for this reflex formation) resulted in significant decrease of MAP/ERK kinase cascade activation at earlier stages of learning, which suggest an important role of serotoninergic system in this cascade activation. The activation of MAP/ERK kinase cascade in 4 hours after training was observed in native as well as in DHT-treated animals, which seems to suggest, switching on nonspecific adaptive processes in response to sensitizing unconditioned stimulus. Thus, MAP/ERK kinase intracellular regulatory cascade playing an important role in neuron survival, processes regeneration and synaptic sprouting plays an important role in the formation of serotonin-dependent food aversion reflex in Helix pomatia.

An efficacy of mexidol, a Russian drug of the new generation, used in 100 mkg during 7 days has been demonstrated in rats in the model of experimentally caused intracerebral posttraumatic hematoma (hemorrhagic stroke). The drug significantly reduced the number of neurological impairments (paresis, riding-arena movements) and increased the animal's survival rate. Mexidol improved learning and memory in rats with hemorrhagic stroke in the passive avoidance test and exerted influence on the locomotor activity in the open field test.

In experiments on rats we studied the effect of potentiated antibodies against S-100 antigen on training a step-down passive avoidance task and choice between drinking bowls with sucrose solution. Peroral treatment with antibodies accelerated inhibition of ineffective and punished locomotor reactions in animals.

The learning effect of phenibut, a beta-phenyl derivative of the inhibitory neuromediator GABA, used in a subcutaneous dose of 40 mg/kg 2 hours before each experiment, was studied in rabbits. The injection of phenibut was shown to enhance not only the inhibitory, but also excitatory components of cerebral cortical neuronal responses to all applied stimuli. The findings support the concept that the GABAergic neuromediator system is involved in the elaboration of internal inhibition and explain the sense of intracerebral processes that ensure both the sedative properties of phenibut and its ability to improve patients' systemic tone and health status when brain dysfunctions are treated.

Learning and memory disorders accompanying epileptogenesis were studied in rats with the use of two experimental models of epilepsy, picrotoxin kindling and kainic treatment. Rise of exploratory activity and decrease in animal's capability for experimental extinction of a response were characteristic of the initial stage of epileptogenesis. It was suggested that a dysfunction of brain hippocampal system can be responsible for cognitive disorders. To reveal their mechanisms, lipid contents were determined in the neocortex and hippocampus in appropriate periods after exposure to epileptogenic factors. Long-term changes in hippocampal lipid spectrum were found five days after the exposure to kainic acid. In particular, after sodium valproate treatment (the compensation of kainic effects), the total content of phospholipids in hippocampus was decreased. The hippocampal sphingomyelin level dropped as a result of picrotoxin kindling. The sphingomyelin changes suggest some recovery processes in hippocampal cells and point to an adaptive role of membrane lipids in the mechanisms of the damaging epiptogenous effects.

In the review the history of food-derived opioid peptides beta-casomorphins (beta-cas) discovery is given. The beta-cas formation in gastrointestinal tract during the beta-casein degradation and the following penetration into the blood are described, in the first place in newborn mammals. The attention is focused on neurotropic activity of beta-cas: their influence on the pain sensitivity, locomotion, anxiety and learning of experimental animals. The beta-cas ability to change the characteristics of mother-infant interaction is specially analysed. The necessity to take into consideration of beta-cas physiological effects on nursing dams and newborns behaviour is noted.

Effects of benzodiazepine tranquillizers (phenazepam, flunitrazepam), antidepressants (amitriptiline, imipramine) and nootropic piracetam injected in supersmall dozes were studied in outbred albino rats. It was found that in supersmall doses (10(-12)-10(-14) mol/kg) all these substances exert characteristic for each of these classes specific effects revealed by means of adequate pharmacological techniques. Benzodiazepine tranquillizers increased the number of punished water lickings in the conflict situation test. Antidepressants increased the number of wheel rotations in the test of the forced swimming in a tank with freely rotating wheels and enhanced a correlation between the number of wheel turns during the first and the second five minutes of the experiment. Nootrop piracetam increased the rate of acquisition of the active avoidance reflex in a shuttle box. The effects of all investigated drugs injected in supersmall doses were not accompanied by side effects, characteristic for them at administration in usual dosages. The conclusion is made, that the action of the drugs injected in supersmall doses is an universal property of psychotropic drugs. When administered in supersmall doses the pharmacological substances still exert their specific activity, but are devoid of side effects.

The effect of the new nootropic drug nooglutyl, a positive modulator of AMPA-subtype glutamatergic receptors, was studied in rats with a model hemorrhagic stroke (HS)--posttraumatic hematoma induced by cerebral tissue destruction in the capsule interna region. Single intraperitoneal injections of nooglutyl (10 and 20 mg/kg) 3-4 h after operation decreased the HS-induced neurological deficiency, restored the coordination of movements, improved the passive avoidance reaction retrieval, and prevented the loss of experimental animals. The results show evidence of a pronounced neuroprotector action of nooglutyl in rats with the HS model.

A chronic deprivation of brain cholinergic functions in rats caused by intracerebroventricular injection of neurotoxin AF64A increases the escape latency in Morris water maze test as compared to control sham-operated animals. Measurements and analysis of rat movement tracks using an original computerized "Behavioral Vision" system revealed the ability of 17 beta-Estradiol and its synthetic isomer J-861 (both administered daily in per os dose 0.2 mg/kg during 7 days before and 10 days after a single intracerebroventricular injection of AF64A) to improve learning of the animals. Directivity of search trajectories was estimated by a novel index of track straightness. The introduction of an index of "passive swimming" made it possible to reveal episodes of immobility in water-maze behavior of AF64A-injected animals. Unlike J-861, 17 beta-Estradiol almost completely eliminated these episodes. The newly developed indices (especially straightness) seem to be very useful in differentiating learning ability of rats from a decrease in their mobility in the Morris water-maze test, in particular, in case of the estrogens under study.

Neurons of the cat motor cortex related to the lifting-withdrawal phase of forepaw placing reaction are preferentially activated by tactile stimulation of the dorsal surface of the forepaw. The placing reaction was altered in such a way that the innate "dorsal placing" was subjected to extinction and was substituted for the newly acquired conditioned reaction in response to the ventral side stimulation. This alteration of placing reaction led to the inversion of the innate input-output relationship in the motor cortex. The neurons related to forepaw lifting-withdrawal began to be activated by tactile stimulation of the ventral rather than dorsal forepaw surface. Local cortical disinhibition by bicuculline application at the recording site qualitatively changed neither normal input-output relationships nor inverse relationships after placing reaction alteration. This suggests that alteration of the sensorimotor coordination in cat motor cortex is underlain by changes in excitatory rather than inhibitory connections.

Single per oral administration of manganese chloride induced an obvious reversible diminishing of locomotor activity in white rats as well as deterioration of avoidance response to unconditioned and conditioned stimuli, prolongation of the conditioning latency, and a temporary deterioration of learning. Chronic manganese intoxication produced an irreversible learning disability and a slight memory disorders.

Protein-peptide complexes involved in learned and natural drinking behavioral patterns were comparatively analyzed in rats. Active immunization with protein-conjugated angiotensin II and beta-endorphin produces some behavioral responses. It is suggested that protein complexes of these peptides play a specific informational role in the systemic organization of learned behavior. The paper discusses whether these complexes perform an important function due to their conformational properties and their participation in the hierarchical organization of integrative processes in the nervous system.

Administration of sodium nitrite, NO-generating agent, in a dose of 11 mg/kg to conscious rabbits eliminates the increased rates of movements to pain reinforcement which occurs as combinations of light flashes with electric cutaneous irritation recur in the control. Along with this, there is a reduction in the intensity and duration of short latent "modally specific" components in the neuronal responses of visual (to light flashes) and sensomotor (to pain reinforcement) regions of a new cortex. There were less changes in the late latent activation components of neuronal responses of the sensomotor and visual cortex to pain reinforcement, an inhibitory pause in visual neuronal responses to light flashes, its uninhibitory action of pain reinforcement after sodium nitrite administration. The findings suggest that sodium nitrite exerts a neurotropic effect on its systemic administration and support the views that there are differences in the neuromediatory provision of transmission of "modally specific" and "modally nonspecific" effects to the neurons of the new cortex on radiation.

The effect of rhodaxon, an adaptogen preparation based on the Rhodiola rosea extract, upon the physical and intellectual working capacity and psychoemotional state of foreign students during their study in a Russian high school was evaluated. It was established that rhodaxon administration provided increase in the amount of veloergometric work accomplished and reliably increased the kinesthesiometric sensitivity. The drug also lead to marked increased in the general condition and a decrease in the level of psychic fatigue and situational anxiety. On the whole, the pharmacological properties of the rhodaxon preparation studied coincided with those reported for the gold root extract. The fact that the rhodaxon preparation contains no ethyl alcohol extends possibilities of the clinical administration of the new preparation.

Physostigmine (0.7-0.8 mg/kg, i.p.) decreased and pentobarbital (13.4-14.6 mg/kg) increased the locomotor and emotional activity of rats in the "open field". Both drugs induced the reversible amnesia to a conditioned reaction in a double T-maze with positive (nutritional) reinforcement. These changes in behavioral activity were correlated with dissociated learning of rats after the injection of the drugs: physostigmine largely decreased the number of errors during learning as compared with pentobarbital. However, in both cases rats reached the learning criterion sooner than the control animals due to the shorter reaction latency (physostigmine) and increase in general motor activity (pentobarbital).

The review is dedicated to description of the phenomenon of dissociated learning. The distinct criteria which discriminate this phenomenon from those similar in appearance are presented. The experimental procedure is described: habituation of an animal, a device for dissociated learning, and the mode of determination of the necessary dose of a drug and injection time. Different versions of dissociated learning which can be gained using the same device, as well as methodical recommendations for researchers in the field of studying this phenomenon. Analysis of the author's data shows that the use of dissociated learning can be promising for studying mechanisms of learning and memory.

Effects of bilateral lesions of the thalamic parafascicular nucleus (Pf) and bilateral microinjections of scopolamine (cholinolytic) and carbacholine (cholinomimetic) into rat neostriatum on the strength of pressing the bar at different stages of acquisition of food-procuring reflex were studied in 51 rats. At the stage of training of food-procuring movements (only strong bar pressings were reinforced) without introduction of a conditioned stimulus, the Pf lesions decreased the rate of learning and increased the number of week pressings. At this stage, scopolamine neostriatal microinjections against the background of the Pf lesions increased the number of strong and did not affect the number of week bar pressings. On the contrary, carbacholine decreased the number of strong and increased the number of week pressings in comparison with the preinjection background. In the trained group of rats, at the stage of reflex restoration (strong bar pressings were reinforced only during the action of a conditioned stimulus) after the Pf destruction, the reflex restoration time depended on the level of presurgery training. Striatal scopolamine injections that primarily after surgery led to a high level of correct reflex realization induced a sharp impairment in reflex performance on a microinjection day, and carbacholine microinjections against the background of low reflex performance did not change this level after surgery.

The influence of 5,6-dihydroxytryptamine (5,6-DHT), which selectively destroyed serotonin terminals, and p-chlorphenylalanine, which inhibited serotonin synthesis, was studied on the long-term sensitization (LTS) in a snail. The membrane mechanisms were analyzed by measuring electrical characteristics of command neurons of defensive behavior LPa3, RPa3, LPa2, and RPa2. Snails injected with saline served as an active control. It was shown that the injected drugs inhibited the LTS in certain concentrations. A significant increase was observed in the membrane potential and the threshold of the action potential generation in the command neurons after 5,6-DHT injection in the doses of 20 and 30 mg/kg (in comparison with the active control). Sensitization of snails injected with saline solution led to the LTS and decrease in the membrane and threshold potentials of the command neurons. After the LTS, changes in membrane and threshold potentials in snails injected with 5,6-DHT were negligible in comparison with those injected with 5,6-DHT but without the LTS. Neither the LTS nor subsequent learning resulted in a further decrease in membrane and threshold potentials. Thus, the neurotoxin injection led to an increase in excitability of command neurons and their depolarization, and the LDS did not elicit further excitability increase. Since the shifts of the threshold and membrane potentials were the same, it was concluded that the increase in membrane excitability was induced by the depolarizing shift of the membrane potential.

New analogue of the AVP(6-9), the D-MPRG was administered intranasally in different doses. The administration improved the process of conditioning. The most efficient dose turned out to be 0/01 mcg/kg. Tetrapeptide administered 1 hour before each learning session and immediately after it accelerated the avoidance conditioning. The peptide effect was more obvious in conditioning with a negative reinforcement. The data obtained suggest that the D-MPRG mostly affects the perception of experimental environment as well as improves the consolidation of memory traces. The peptide was also shown to delay extinction of previously learned skills.