Acquisition of a conditioned avoidance reflex and morphometric characteristics of the sensorimotor cortex in rats subjected to social deprivation in early ontogenesis.

Male Wistar rats were subjected to social deprivation from day 22 to day 70 of postnatal development to form a group of isolants. Measures of learning of a passive avoidance and the results of training to active avoidance of painful electrical stimulation in these rats were significantly lower at age 110-120 days than in control rats. The characteristics of movement activity in isolants during training and testing, as well as in the open field test, probably resulted from their high levels of anxiety. Morphometric measurements of the numbers of neurons, satellite glial cells, and free glial cells in the sensorimotor area of the neocortex showed that isolants had a significantly lower density of neural elements per unit area, which resulted from a decrease in the afferent flow due to social isolation.