SPLTRAK Abstract Submission
Continuous Tracking of Memory Formation Recording of Gustatory Cortex Neuronal Ensemble Activity Following Conditioned Taste Aversion in Freely Behaving Rats
Elor Arieli1, Nadia Younis1, Daniel Udi1, Anan Moran1,2
1Department of Neurobiology, Faculty of Life Science, Tel Aviv University, Tel Aviv, Israel
2Sagol School of Neuroscience, Tel Aviv University , Tel Aviv, Israel

Neuronal activity in sensory cortices changes following learning, such as in the gustatory cortex (GC) after conditioned taste aversion (CTA) wherein a novel palatable taste becomes aversive following pairing with malaise. These changes, however, have been found using "snap shots" taken 24 hours apart, and thus do not allow fine temporal description of the response changes over time. Insights about the time course of these changes come from molecular studies showing different molecular cascades that span over hours following the CTA induction. To reveal the neuronal activity changes over time we implanted rats with electrodes in the GC and intraoral cannula for precise taste deliveries, and tracked ensembles of neurons for 48 hours; before, during and after CTA. Our results show that changes in neuronal response dynamics start approximately 1h after CTA induction and end about 8h post CTA, with the main changes occurring 3-6h post CTA. This timing is similar to time of the reported molecular processes. Interestingly, these changes were uncorrelated with changes in their baseline (BL) activity over time. In contrast, high correlations were observed in BL and taste response activity between different neurons, supporting the idea of global changes that govern neuronal activity following learning. Additional analyses of network level synchrony and delta-gamma modulation show similar increases 3 hours post CTA. Together, our results show that long-term electrophysiological changes that occur following taste aversion learning occur in the same time scales of the molecular processes. Moreover, these changes seem to be mainly governed by a network level organization and to a lesser extent by the state of the single neuron.