[The acute extinction of orientational-exploratory activity in rats in the early periods after irradiation with high-energy helium ions].

Study of orienting-investigatory activity level, presence of grooming, manifestation of experimental neurosis, changes of rats motor activity after irradiation by helium ions in the beginning and at the end of the test at initial testing (using Dombrovskaia's maze) and also at repeated presentations with short time intervals, relation of latency and time of locomotor reaction revealed differences in the character of changes of correlation and intensity of nervous processes at different levels of doses: strengthening of inhibition processes at higher mid-lethal dose with a sharp increase of the CNS excitability and deficiency of internal inhibition process in the case of repeated presentations of the test.