The effect of vital stress on the bioelectric activity of the brain and the behavior of female rats

Abstract

BACKGROUND: Identification of possible biomarkers that assess the severity of post-traumatic stress symptoms is an urgent task for the early diagnosis of post-traumatic stress disorders. The manifestation of emotional states, both human and animal, is reflected in altered behavior and in the violation of the ratio of basic rhythms and cross-correlation connections in the brain electroencephalogram, which indicates the development of pathological processes. AIM: The aim of the study was to analyze the behavior and electrocorticogram indicators of rats in the delayed period (on day 7) after life-threatening stress, as a way to predict the formation of post-traumatic stress disorder. MATERIALS AND METHODS: The study was performed on mature female Wistar rats weighing 180200 g (n = 40). Mental trauma was modeled by the circumstances of experiencing the situation of the death of a partner from the action of a predator and the threat to their own life when placing rats in a terrarium with a tiger python. In rats, the behavior in the Open Field test and the bioelectric activity of the brain in the frontal and occipital regions on the left and right were analyzed before and on the 7th day after stress exposure. RESULTS: It is shown that in the delayed period after vital stress in female rats, there is a decrease in motor and research activity and altered emotional behavior in the Open Field test. Reduction of interhemispheric asymmetry in the index of theta and delta activity and changes in cross-correlation connections in the right hemisphere, as well as changes in the ratio of the main rhythms and cross-correlation connections of the electroencephalography. The revealed changes in the delayed period indicate a pronounced aversive nature of the psychotraumatic effect. CONCLUSIONS: Life-threatening stress is caused by changes in electrophysiological and behavioral parameters in experimental animals not only at the time of exposure, but also in the long-term period.