Oscillatory interaction between amygdala and hippocampus coordinates behavioral modulation basedon reward expectation

The aim of this study is to examine how the amygdala and hippocampus interact for behavioral performance modulated by different Reward-expectations(REs). We simultaneously record edneuronal spikes and local field potential from the basolateralamygdala and hippocampal CA1 while rats were performing alightside discrimination task with different expectations of a high or low probability of reward delivery. Here, were port the following results. First, the rats actually modulated their behavioral performance on their expectations of a high or low probability of reward. Second, we found more neurons related to RE in the amygdala and moreneurons related to task performance in the hippocampus. Third, aprominentin creas ein the coherence of high-frequency oscillations(HFOs)(90-150Hz) between the amygdala and the hippocampus was present during high RE. Fourth, coherent HFOs during inter-trialintervals and the tacoherence during trials had significant correlations with the behavior algoal-selection time. Finally, cross-frequency couplings of LFPs within and across the amygdala and hippocampus occurred during ITI. These results suggest that the amygdala and hippo campus have different functional roles in the present task with different REs, and the distinctive band of coherence between the amygdala and thehippocampus contributes to behavioral modulation on the basis of REs. We propose that the amygdalainfluences firingrates and the strength of synchronization of hippocampalneurons through coherent oscillation, which is a part of the mechanism of how reward expectations modulate go al directed behavior.