Longitudinal Study of Chronic Stress Induced Electrophysiological Alterations in Pre-Frontal Cortex, Ventral and Dorsal Hippocampus in Freely Moving Rodents

Chronic stress impairs synaptic plasticity and has a significant deleterious effect on brain networks. In order to study the electrophysiological alterations prompted by chronic stress on some of the relevant brain areas involved in the stress response, local field potentials from freely moving rats were recorded from the pre-frontal cortex, ventral and dorsal hippocampus during the time course of a chronic unpredictable stress protocol. A stress induced increase of ventral hippocampus and pre-frontal cortex activity, as measured through power spectral density analysis, was observed. These increases occurred for the theta, beta and gamma bands in the Stress group animals when the first and last days of the stress protocol were compared. These findings correlated with increased levels of plasmatic corticosterone and anxiety-like behavior in the elevated-plus maze.