Abstract
Postrhinal cortex, rodent homolog of the primate parahippocampal cortex, processes spatial and contextual information. Our hypothesis of postrhinal function is that it serves to encode context, in part, by forming representations that link objects to places. To test this hypothesis, we recorded postrhinal neurons and local field potentials (LFPs) in rats trained on a two-choice, visual discrimination task. As predicted, many postrhinal neurons signaled object-location conjunctions. Another large proportion encoded egocentric motor responses. In addition, postrhinal LFPs exhibited strong oscillatory rhythms in the theta band, and many postrhinal neurons were phase locked to theta. Although correlated with running speed, theta power was lower than predicted by speed alone immediately before and after choice. However, theta power was significantly increased following incorrect decisions, suggesting a role in signaling error. These findings provide evidence that postrhinal cortex encodes representations that link objects to places and suggest postrhinal theta modulation extends to cognitive as well as spatial functions.
► Postrhinal cells encode representations that link objects to places ► Postrhinal neuronal activity correlates with egocentric motor responses ► Theta power in postrhinal cortex correlates with running speed, task phase, and decision outcome ► A substantial proportion of postrhinal neurons are phase locked to theta
Memory for context, the complex environment in which events occur, is a critical component of episodic memory. Furtak et al. show that postrhinal cortex, the rodent homolog to primate parahippocampal cortex, encodes context, in part, by configuring objects and places.