André Fenton, Center for Neural Science, New Yorck University

We will focus on the microstructure of oscillatory events in the local field potential (LFP) and their interactions with the spike trains of spatially tuned cells in the mouse and rat as the animals perform place avoidance tasks on a rotating arena. The tasks require a functional hippocampus and that the subject judiciously uses information from the two dissociated spatial frames, one stationary the other rotating. The fundamental physiological characteristics like the power and frequencies in the LFP and the firing rates of spatially-tuned cells are stable across the stationary and rotating conditions. However, we find that the microstructure in the time series of anatomically organized oscillatory events depends on experience, indicates the subject’s current knowledge, and reveals abnormalities when subjects make cognitive errors and express cognitive inflexibility. We find that place cell discharge is organized within the temporal infrastructure of these oscillatory events in the LFP, and that this organization depends on what the animal has learned, is doing or attempting to do. We find in these conditions that the temporal interactions within the network of spatially tuned cells appears to describe the cognitive state and spatial information processing effort of the animals better than the stability of the spatial tuning of the neurons, suggesting that the temporal interactions within the hippocampal and related neocortical networks provide a timing-based functional framework for information processing that is itself recruited to represent memories and perhaps even the physical space of the environment.

Organized by

Michael Brecht