Theta Rhythms Coordinate Hippocampal–Prefrontal Interactions in a Spatial Memory Task
(A) Firing rate of a single mPFC neuron split into four trial types (shown by arrows). This neuron tended to fire at higher rates during runs in the choice direction, with the central arm firing highest during F2 → C2 trials. The magnified boxes show the central three-quarters section of the central arm. White lines mark the boundary of the positional pixels traversed by the rat on F1 → C1 trials. These are superimposed on the firing-rate map for F2 → C2 trials, showing the overlap between positions visited on both trial types.
(B) Central-arm firing rates of both mPFC (blue) and CA1 (black) neurons tended to distinguish between runs in the forced-turn and choice directions (directional index > 0) and choice-direction runs in either F1 → C1 or F2 → C2 trials (preference index > 0; see Results). However, there was no overall tendency for CA1 or mPFC populations to fire at higher rates during any one epoch or trial type.