Interaction of the Medial Prefrontal Cortex, Ventral Hippocampus, and Basolateral Amygdala during Performance of a Conditioned Avoidance Reflex

Abstract

The interaction between the medial prefrontal cortex, the ventral hippocampus, and the basolateral amygdala was studied during execution of a conditioned avoidance reflex. Slow δ activity at 1–4 Hz was recorded during the prestimulus period, with a source meeting the “Granger causality” criterion located in the prefrontal cortex, along with a θ rhythm at 6–8 Hz with a source in the hippocampus. The conditioned avoidance reflex was accompanied by a burst of high-frequency synchronized θ activity (8–11 Hz) and disappearance of δ activity on entry into the safe sector of the chamber. All structures showed cross-frequency phase-amplitude modulation of the amplitude of the gamma-activity (frequency from ~30 to ~120 Hz) envelope by the δ and θ rhythms. Acquisition and simplification of the conditioned reflex were accompanied by suppression of the power and interstructure synchronization of the θ rhythm during the conditioned reflex, though not during the intersignal period.