Peculiarities of the higher nervous activity of animals irradiated in the antenatal period with ionizing radiation. Report 5. Peculiarities of the higher nervous activity in early postnatal ontogenesis in puppies irradiated during embryonic development

Abstract

Conditioned reflex activity was studied during the period of early postnatal ontogenesis by the olfactory and shaking methods in dogs irradiated with X-rays on the 45th or the 20th day of embryogenesis in a dose of 200 R. There were 38 puppies under observation: 15 control, 9 irradiated on the 20th day and 14-on the 45th day of embryogenesis. The puppies of experimental litters developed very unevenly (as compared to control) both in somatic respects and in respect to the higher nervous activity. At the age of 2 months the difference in weight between various experimental puppies constituted about 150%, whereas in control animals it did not exceed 10–15%. The connective function of the cerebral cortex in the experimental puppies was deranged right from their birth and up to the age of 6 months. Conditioned reflexes and especially differentiation in the experimental puppies appear at a later date. Frequent occurrence of phasic conditions (paradoxical, ultraparadoxical) in irradiated animals points to the functional deficiency of cortical cells. In puppies irradiated on the 20th day of embryogenesis the neurodynamic disturbances and especially the processes of cortical inhibition were seen to be more marked than in those irradiated on the 45th day.