[Effect of the motivation factor on the utilization by animals of prior experience in an altered learning situation].

At studying the use by the rats of previous experience in conditions of change of the dominant need and change of learning situation, data were obtained that allowed to evaluate differently the significance of drinking and defensive motivations as a factor providing for dissociated learning of animals. Significance is discussed of motivation factor during the use by the rats of one or other behavioural strategies in the process of learning.

[Ontogenetic features of the development of evoked potentials in the visual cortex of the alert rabbit].

Formation of optical EPs was studied in alert rabbits during postnatal ontogenesis. The pathways of the transmission of light stimuli to the brain cortex were found to develop heterogeneously causing the EPs to have different forms in the early stages of ontogenesis.

[Effect of destruction of the hippocampus and septum on learning in the rat in "negative transfer" situations].

Intact rats and rats with lesions of the hippocampus and septum were trained to repeated switching-over of the habit of choosing the reinforced side of the maze as well as to alternation of reinforced side choice. Repeated switchings-over of the habit impedes the subsequent elaboration of the choice alternation ("negative transfer"). In operated animals, the interferating effect of the previous experience is more expressed.

[Conditioned reflexes before and after lesioning the substantia innominata in the cat].

It has been shown that bilateral lesion of the substantia innominata has caused temporary depression of unconditioned and conditioned alimentary reflexes, disturbances of the elaboration and performance of conditioned reflexes. It is suggested that the latter produced by the operative memory disturbances.

[Subcortical structures of the brain and the behavior of white rats].

Conditioned food and defensive reflexes have been studied in white rats following bilateral injury of paleo-, archi-, neostriatum, substantia nigra and paleocortex. It has been shown that these deep structures play a role in the operational memory of animals.

[Conditioned reflexes following destruction of the deep structures of the brain].

The role and the relative significance of paleo-, archi- and neostriatum as well as Corpus Luysii, substantia innominata, substantia nigra, nucl. ruber and the hippocampus, in the mechanism of purposeful behaviour of animals, were studied on cats and rats. It has been shown that the above structures, together with the cerebral cortex, take part in operational memory.

[Participation of the basal ganglia in the mechanism of visual memory in the rat].

Studies have been made of the effect of bilateral injury of paleo-, archi- and neostriatum, as well as that of the nucleus ruber on adaptive behaviour in albino rats. It was shown that injury of the basal structures of the brain results in disturbances of optimal visual choice of a food signal. The data obtained are discussed from a standpoint of disturbances in operative memory of visual signals.

[Role of the globus pallidus in memory mechanisms].

The role of the pallidum in memory mechanisms was studied in cats by different methods of conditioned reflexes. It has been shown that a bilateral partial lesion of the Globus pallidus leads to "forgetting" sequences in delayed alternation and electrical punishment in previous experiments as well as to disturbances of the perceptual memory.

[Effect of damage to the substantia nigra on conditioned reflex activity in animals].

Effects of the Substantia nigra injury on conditioned activities were studied on rats and cats by defensive and feeding methods, respectively. Bilateral injury of the Substantia nigra led to temporary disappearance of conditioned defensive and feeding motor reflexes, to prolongation of latency and duration of motor reaction. In cats the injury of the Substantia nigra produced a 30--40% decrease of the accuracy of food direction choice.

[Role of the hippocampus in conditioned reflex activity].

The role of the hippocampus in animals' conditioned activity was studied in experiments on rats and cats with ablated hippocampus. It was shown that in rats the ablation leads to a statistically significant slowing down in learning of the avoidance reaction. The effect becomes stronger in stress situation.

[Conditioned motor-alimentary reflexes in cats following ablation of the body of Luys].

Alimentary conditioned motor reflexes in cats were elaborated in special chambers. Subsequently, the subthalamic nucleus was damaged, first on one and then on the other side. After its unilateral destruction, temporary disturbance in the cat behaviour was observed disappearing within 2--3 weeks.

[Role of the globus pallidus in establishing delayed responses in cats].

Unilaternal ablation of the pallidum leads to acute disturbances in delayed reaction in cats. In the case of a 3 or 5 sec delay the accuracy of finding the food behind the screan or of the choice of the side of reinforcement drops by 30 to 40%; in the case of a delay of 10 sec this accuracy drops by 55 to 60%. Along with this and as a natural result, it takes the cat a longer time to get to the place where the food is kept.

[Electrophysiologic study of the connections of the 2d somatosensory area of the cortex with the neo-, paleocortical and striate formations of the brain].

2nd somatosensory area (C2) was shown to have modulating influence on evoked activity of the 1st somatosensory and visual areas. Electrical stimulation of C2 evoked short latency potentials in the structures of paleocortex (hippocampus) and striatum (putamen, caudate nucleus). Analysis of the data obtained here and elsewhere (19) suggests the important role of C2 in mechanisms of selection, comparison and integration of adequate sensory information under conditions of uncertainty, for the programming of behaviour.

[Comparative assessment of the role of the primary and secondary somatosensory regions of the cerebral cortex during conditioned reflex behavior in animals].

The first (SI) and second (SII) somatosensory cortical areas were ablated in one group of cats after preliminary learning of tactile differentiation of rough and smooth surfaces of the floor coating in a special chamber. Somatosensory areas were ablated in another group after learning an adequate choice of the reinforcement side in response to a bell and a metronome. Unilateral and bilateral ablation of SI affected but little the elaboration and achievement of the above acts.

[The role of the pallidum in regulating cortical activity].

Bilateral ablation of the pallidum halves the duration of extinction of conditioned motor food reflexes and contributes to 30 to 50% extinction of the electro-defensive reflexes. Pallidum functional depression by potassium chloride or novacaine leads to a temporary total depression of conditioned motor food reflexes. Depending on the frequency of pallidum stimulation, synchronization or desynchronization of the cortical bioelectrical activity is observed.

[Conditioned alimentary motor reflexes in cats following destruction of the scorpula].

Bilateral ablation of the putamen results in temporary disappearance of natural as well as artificial conditioned motor reflexes in cats. Further training is necessary for their reestablishment. Restored conditioned reflexes appear with a long latency.