(The) effect of voluntary choice on hippocampal theta sequence

Abstract

Hippocampal place cells show sequential firing pattern in hippocampal theta oscillation with 6-10Hz. It is called ‘Theta sequence’, and expected to function for spatial planning. Although, many researchers study about the mechanism and function of theta sequence, it’s still unclear. In this study, we analyzed electrophysiological recording data obtained from the animal’s hippocampus while performing the spatial sequence memory task. In the results, we observed that theta sequence mainly occurred in reward zone, independent whether voluntary choice. Also, the difference of coactivation probability of place cells between correct and forced trial are oppositely significant in reward zone and return zone, and track cells show higher participation in theta sequences in voluntary choice. We can observe that alternative trajectory cells also participate in theta sequence, but there is no significant effect from voluntary choice. In conclusion, we suggested that the theta sequence represents the spatial information differently between voluntary choice and involuntary choice. In addition, we suggested that the theta sequence represents the information about unexperienced trajectory. Therefore, this study shows some evidences of the spatial planning function of the theta sequence.