Hippocampal-Prefrontal Interactions during Spatial Decision- Making
decision-making, spatial navigation, in vivo electrophysiology, neuronal oscillations, brain rhythms, LFP, coherence, synchrony, directionality, hippocampus, prefrontal cortex.
The hippocampus has been linked to memory encoding and spatial navigation, while the prefrontal cortex is associated with cognitive functions such as decision-making. These two areas are hypothesized to communicate in tasks that demand both spatial navigation and decision- making processes. However, the electrophysiological signatures underlying this interplay remain to be better elucidated. To investigate the dynamics of the hippocampal-prefrontal interactions, we have analyzed local field potentials recorded from rats performing a spatial alternation task in an 8-shaped maze. We found that both theta (6-10 Hz) and beta (23-30 Hz) phase coherence peak around the choice point area of the maze. Moreover, Granger causality points to a hippocampus- >prefrontal cortex directionality of information flow at theta frequency, peaking at starting areas of the maze, and on the reverse direction at delta frequency, peaking near the turn onset. Additionally, we found the patterns of phase-amplitude cross-frequency coupling within and between the two regions show spatial selectivity. In all, our results reveal maximum electrophysiological interactions between the hippocampus and the prefrontal cortex near the decision-making period of the spatial alternation task. These results corroborate the hypothesis that a dynamic interplay between these two regions takes place during spatial decisions.