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A multi-factor variance analysis revealed that the 2-amino-5-phosphonovalerian acid (APV) effect was manifested in monkeys by a decrease in the number of correct responses entailing a two-fold shortening of the short-term information storage, as well as by an augmentation of the motor responses' time. The correct responses' probability depended on the APV diffusion localisation in the cortex whereas the motor responses' time did not depend on it. The APV effect was accompanied by a desynchronisation of the unit activity in fields 46 and 17. Neurophysiological correlates of cognitive functions, are discussed.

With the aid of a multichannel leads the unit activity was recorded in the 17th and 8th cortical fields along with registering behavioural data in Rhesus monkeys. Multi-factor variance analysis revealed that the 2-amino-5-phospho-valeric acid (APV) effect involved a significant worsening of the monkeys' behavioural characteristics: duration of the short-term memory shortened (2-4-fold), motor reactions' time increased, and the changes of cognitive characteristics were always followed by significant rearrangements of the unit activity in the above areas. The data obtained suggest that these cognitive dysfunctions are due to a desynchronisation of unit activity in different areas of the cortex including the neuronal assemblies maintaining the short-term memory mechanisms associated with the glutamatergic structures.

Administration of amysil blocking M-cholinoreceptors, and APV the duration of short-term storing of information was decreased whereas the motor response time increased. This was followed by a considerable desynchronisation of the unit activity. The NMDA and APB improved the characteristics of the short-term memory. The role of synchronisation of the information processes in the short-term memory mechanisms and participation of cholinergic and glutamatergic systems in them, are discussed.

The effect of the NMDA glutamate agonist on cognitive characteristics and short-term memory (SM) was studied in rhesus monkeys. The NMDA effect manifested itself in doubling the SM term and in changing of the unit activity in the prefrontal cortex. The NMDA also induced a considerable increase in the cross-correlation coefficients between the unit responses in visual and prefrontal cortex. The data obtained suggest that the glutamatergic structures of prefrontal cortex take part in the processes of visual recognition and the SM in monkeys. The effect seems to improve the short-term memorizing of a visual information.

During a 2.5-min. hypoxia in monkeys, a rearrangement of the unit activity occurred in the visual and prefrontal cortex. Following this, the motor response in delayed visual spatial reaction tack did not restore during several hours. The rearrangement involved appearing of sequential phases of hyperactivation and inhibition. Duration of the posthypoxic inhibition and ratio of posthypoxic hyperactivation frequencies to the background one were significantly greater in the prefrontal cortex than in the visual one.

In behavioral experiments on monkeys tested for a delayed visual differentiation of different colours stimuli, neuronal pools were recorded simultaneously in the visual, prefrontal and inferotemporal cortex. Wrong motor responses were always followed by considerable readjustments of the unit activity patterns whereas in right decisions a synchronisation and a cross-correlation occurred between neuronal pools. Possible mechanisms of the decision making and the reasons for the desynchronisation in wrong responses, are discussed.

Characteristics of visual recognition were impaired by amysil influence in monkeys. This was accompanied by a considerable activation of unit activity in the prefrontal cortex. Amysil induced a considerable drop in the cross-correlation coefficients between simultaneous responses of neuronal populations in prefrontal and inferotemporal cortex.

The antioxidant oxymetacil improved cognitive characteristics and activated neuronal activity in the monkey prefrontal area in the process of delayed visual differentiation of different colour stimuli. It also considerably increased the mutual correlation coefficients between neuronal responses in prefrontal and inferotemporal cortex. The data obtained suggest a contribution of neuronal structures of these areas into the improvement of the cognitive characteristics.

Administration of oximetacyl considerably improved the cognitive characteristics of the processes of delayed visual recognition, increased auto- and cross-correlation coefficients in the responses of groups of neurons. The data obtained suggests nootropic properties of oximetacyl and participation of visual cortex of the monkey brain in realisation of these properties for improvement of the cognitive characteristics.

Unit activity was studied in the visual cortex prior to and after amyzyl administration in monkeys trained for delayed visual differentiation of different colour stimuli. The data obtained suggests that the cholinergic mechanisms of the visual cortex are involved in the visual recognition and seem to play different functional roles at different stages of the behaviour.

A normal differentiation between black and white visual stimuli lesioned by phthoracisine can be restored by oxymetacyl administration (3 mg/kg) in monkeys. The colour differentiation is restored after the dose 4 mg/kg. The data obtained suggest correcting effect of oxymetacyl.

In monkeys (Macaca mulatta) instrumental reflex was elaborated with differentiation of black-and-white and colour visual stimuli in condition of systemic administration of pharmacological preparations selectively influencing the functional state of cholinergic brain structures. Differentiation of black-and-white and colour stimuli is not disturbed by atropine (0.1 mg/kg) and amizile (up to 1.5 mg/kg) injections; at greater doses frustration of the instrumental reflex takes place. Differentiation of black-and-white and colour stimuli is disturbed at injection of various doses of antidepressant phthoracizine: 5 mg/kg and 7 mg/kg, respectively. These disturbances are restored by the injection of definite doses of galantamine; for correction of colour differentiation a greater dose is required. The obtained data point to differences in neurophysiological and neurochemical processes responsible for black-and-white and colour vision.

It was demonstrated in experiments on 8 rhesus monkeys with suturation of 16 nerves that the relative number of regenerated myelinated fibers was 83.2-96.4% of the initial number in application of sutures with the use of microsurgical techniques and 73.8-81.5% in application of sutures without an operating microscope. The average number of regenerated nonmyelated fibers was 74.3-95.6% of the initial number in the first case and 62.2-77.4% in the second case. In all experiments the mean values of the corresponding indices had no statistically significant differences whatever the method of suture application. A 8/0 supramide thread passed atraumatically through the perineurium induced neither an active cellular reaction in the tissues nor changes in the nerve fibres.