Distinct Roles of Parvalbumin- and Somatostatin-Expressing Interneurons in Working Memory

Inhibitory interneurons are thought to play crucial roles in diverse brain functions. However, roles of different inhibitory interneuron subtypes in working memory remain unclear. We 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. PV interneurons showed weak target-dependent delay-period activity and were strongly inhibited by reward. By contrast, SOM interneurons showed strong target-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. •Roles of parvalbumin and somatostatin neurons in working memory were investigated•Somatostatin neurons contributed to target-dependent delay-period activity•Reward delivery strongly suppressed parvalbumin neuronal activity•These results suggest distinct roles of different interneurons in working memory Kim and colleagues found different discharge characteristics and stimulation effects of parvalbumin- and somatostatin-expressing interneurons in medial prefrontal cortex of mice performing a working memory task. Their results suggest distinct roles of parvalbumin- and somatostatin-expressing interneurons in working memory.