Theta Rhythms Coordinate Hippocampal–Prefrontal Interactions in a Spatial Memory Task

TLDR

Decision‑making depends on coordinated activity across brain regions, with the prefrontal cortex integrating hippocampal spatial maps and mnemonic route‑rule information to guide behavior. Simultaneous tetrode recordings from CA1 and medial prefrontal cortex revealed that correlated firing between these areas is selectively enhanced during spatial working memory, enabling hippocampal spatial signals to enter a broader decision‑making network. During spatial working memory tasks, hippocampal–prefrontal correlations and 4–12 Hz theta coupling increase, indicating that theta rhythms coordinate the timing of independent neural activities to allow selective interaction based on behavioral demands.

Abstract

Decision-making requires the coordinated activity of diverse brain structures. For example, in maze-based tasks, the prefrontal cortex must integrate spatial information encoded in the hippocampus with mnemonic information concerning route and task rules in order to direct behavior appropriately. Using simultaneous tetrode recordings from CA1 of the rat hippocampus and medial prefrontal cortex, we show that correlated firing in the two structures is selectively enhanced during behavior that recruits spatial working memory, allowing the integration of hippocampal spatial information into a broader, decision-making network. The increased correlations are paralleled by enhanced coupling of the two structures in the 4- to 12-Hz theta-frequency range. Thus the coordination of theta rhythms may constitute a general mechanism through which the relative timing of disparate neural activities can be controlled, allowing specialized brain structures to both encode information independently and to interact selectively according to current behavioral demands.