Simultaneous Temporal and Rate Coding in the Hippocampus


March 10, 2015 - 10:00am
NW 453
About the Speaker
Honi Sanders (Brandeis University)

Place cells in the hippocampus preferentially fire when an animal is in a particular location in a given environment, so the population collectively represents the spatial location of the animal. In addition, the firing rate of place cells can change by an order of magnitude in response to non-spatial (e.g. sensory or task-related) information. Not only is information conveyed in the firing rate of place cells (rate remapping), the precise timing of spikes with respect to the ongoing theta cycle (phase coding) has been hypothesized to provide a substrate for linking ordered events. A key question that arises from these facts is how the same cells organize their firing to provide two separate streams of information through two separate aspects of its firing behavior, spike rate and spike timing. The work to be presented deals with in vivo extracellular recordings of place cell spiking activity and the local field potential in dorsal CA1 and CA3 of rats. We find that changes in firing rate of place cells on the central arm during different trajectories does not cause degradation in the precision of the theta phase of spikes at a given spatial location. This work suggests that place cells in the hippocampus are able to simultaneously code for two different variables with different properties of their firing pattern.