Interrelationships of hippocampal electroencephalogram, visually evoked response, and behavioral reactivity to photic stimuli in rats.

Abstract

Examined the averaged visually evoked responses (VERs) at the cortex, hippocampal slow-wave rhythms, and behavioral activity of 8 male albino Holtzman rats in response to repetitive series of photic stimuli under "nonappetitive" conditions (no contingencies attached to stimuli) and "appetitive" conditions (stimuli signaled delivery of food pellets). Habituation of behavioral reactivity to flashes was associated with elaboration of the VER and shift of hippocampal slow-wave activity from high toward low frequencies. Appetitive conditions which progressively increased behavioral reactivity to flashes reduced VER components and shifted hippocampal slow-wave patterns toward higher frequencies. Significant interrelationships among hippocampal EEGs, movement patterns, and "ascending" processes that act upon sensory channels (VERs) would appear to reflect phasic operations of brainstem and diencephalic arousal mechanisms. (33 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved)