Somatostatin interneurons in auditory cortex regulate cortical representations and contribute to auditory perception

In the mammalian neocortex, somatostatin (SOM)-expressing GABAergic interneurons serve as a critical circuit component, receiving diverse inputs and targeting various types of cortical neurons. However, their role in perception and cognition remains not well understood. In this study, we employed cell-type specific imaging and perturbation during an auditory perceptual decision task to investigate the contribution of SOM interneurons. Two-photon calcium imaging revealed that auditory cortex (ACx) SOM interneurons exhibit not only frequency-selective responses but also selectivity to categorical choices. Simultaneous optogenetic inactivation and two-photon imaging revealed that SOM interneurons refine the frequency discriminability of auditory cortical neurons and contribute to their selectivity to the categorical decision boundary. Moreover, bilateral chemogenetic inactivation of ACx SOM interneurons impaired behavior-level perceptual categorization. Our findings provide a mechanistic understanding on the functional significance of SOM interneurons in auditory cortical processing and perceptual categorization, linking cell-type specific cortical circuit computations with perceptual functions.