[Structure of the neocortex of the Baikal ringed seal (Pusa sibirica Gm.)].

The sulci and gyri of the neocortex, as well as cyto-, synaptoarchitectonics and neuronal composition of the sensomotor (brain area) have been studied in the Baikal ringed seal. The structure of the sulci and gyri have been found to be similar to that in carnivores. The following specific features have been revealed in the brain of this endemic species: a thick layer I, presence of giant pyramidal cells in the layer III, large mitochondria in the presynaptic parts and dendrites.

Influence of extirpation of the sensorimotor area of the cortex on the formation of conditioned reflexes in response to a complex signal in the ontogenesis of the cat.

The influence of the extirpation of the sensorimotor cortex (SMC) on the formation and maintenance of a previously developed alimentary conditioned reflex to a simultaneous complex stimulus (light + sound) with extinction of the reaction to unreinforced components of the complex signal was studied in kittens aged 39 days to 4 months. The extirpation of the SMC prior to 2.5 months of age had no influence on either the formation or maintenance of the conditioned reflex to the complex signal developed prior to the operation.

[Effect of extirpation of the sensorimotor cortex on the formation of conditioned reflexes to a complex signal in the ontogeny of the cat].

In kittens of the age from 39 days to 4 months the influence was studied of the sensorimotor cortex (SMC) ablation on formation and preservation of previously elaborated reflex to a simultaneous complex stimulus (light + sound) with extinction of reaction to nonreinforced components of the complex signal. It is shown that SMC ablation in the age up to 2.5 months does not affect the formation or preservation of the conditioned reflex.

[Maturation of thalamic inputs into the association area of the neocortex during postnatal ontogeny in the cat].

Thalamic afferents into the sensorimotor and parietal cortex (area 7) were studied using the method of retrograde axonal transport of horseradish peroxidase (HRP) in kittens of three age groups. Following HRP injection into the sensorimotor cortex of 2 and 3-day kittens labeled cells were found in the VPL, VPM, MD, CM and CL nuclei. In 21-30-day kittens labeled cells were also revealed in VL.