Functional Connectivity Between Prefrontal Cortex And Striatum Modulated By Reward

The prefrontal cortex and striatum are two important brain regions in the brain, the functional connectivity between them plays an important role in cognitive processes. Previous studies have found that prefrontal cortex and striatum involved in higher cognitive processes, such as behavior decision, value computation, reward processing information, learning and memory. However, most of these achievements are the data analysis based on the single neuron activity, there is little about local field potential (LFP) or the lack of the point that look the prefrontal and striatum as a whole to study the functional role in cognitive processes. Therefore, this paper will further study the reward cognitive experiment from the perspective of LFP so as to explore the mechanism of their connection.To investigate interactive functions between the two areas in reward processing, we recorded local field potentials (LFPs) simultaneously from the two areas of two monkeys performing a reward prediction task (large reward vs small reward). Through the analysis of the recorded data, we removed the noise signal generated by the month movement and obtain the data to be analyzed. Then, we filtered the LFP signal to some frequency bands that were beta, low gamma and high gamma bands. Based on these data, we used the non-standard method and standard method to estimate power spectrum of the two reward conditions. The results showed that the PFC and striatum could encode the reward information in the beta band. The reward information was also found in the high gamma band in the PFC, not in the striatum. We calculated the phase-locking value (PLV) to estimate the strength of phase synchrony between the signals from the PFC and the striatum. It was found that significant differences occurred between PLVs in different task periods and in different frequency bands. The PLVs in small reward condition were significant higher than that in large reward condition in the beta band. In contrast, the PLVs in the high gamma band were stronger in large reward trials than in small trials. These results suggested that the functional connectivity between the PFC and striatum depended on the task periods and reward conditions. The beta synchrony between the PFC and striatum may regulate behavioral outputs of the monkeys in the small reward condition and the gamma rhythm is mainly involved in the cognitive processes such as attention, stimulus choice and the behavior preparation.