Role of prefrontal interneuron in working memory and outcome processing

Abstract

Inhibitory interneurons are thought to play crucial roles in diverse brain functions. However, specific roles of different inhibitory interneuron subtypes in working memory and outcome processing remain unclear. I found distinct activity patterns and stimulation effects of two major interneuron subtypes, parvalbumin (PV)- and somatostatin (SOM)-expressing interneurons, in the medial prefrontal cortex of mice performing a spatial working memory task or classical conditioning task. PV interneurons showed weak target-dependent delay-period activity. PV interneurons were strongly inhibited by reward and activated by punishment. By contrast, SOM interneurons showed strong target- or cue-dependent delay-period activity and only a subtype of them was inhibited by reward. Furthermore, optogenetic stimulation of PV and SOM interneurons preferentially suppressed discharges of putative pyramidal cells and interneurons, respectively. These results indicate different contributions of PV and SOM interneurons to prefrontal cortical circuit dynamics underlying working memory and outcome processing.