A shared role in error signaling by a shared cortical cell type
Single cell transcriptomic studies have revealed a common set of inhibitory cell types across the cerebral cortex. Yet, despite these commonalities in cell type composition, different cortical regions serve highly distinct sensory, cognitive and motor functions. How can the same cell types serve such wide-ranging functions across areas? Do they implement a common underlying computation that gives rise to different functions in different areas? Toward addressing this question, we focused on a precise subtype of somatostatin inhibitory neurons – termed Sst44 neurons – that we previously discovered via a new cell type-specific enhancer virus. I will discuss our findings where we compare the activity of Sst44 neurons across three regions highlighting sensory, cognitive and motor modalities of the cortex: the visual cortex, the posterior parietal cortex, and the premotor cortex. We identify a common error signaling role for Sst44 neurons that is tailored to the modality of each cortical region. In addition, we find that instead of responding to errors on the first trial, Sst44 neurons respond to repeated occurrences errors, suggesting that these neurons serve a longer-term role in error signal processing. Finally, we show that Sst44 neurons are required for learning. These data point to a general role for Sst44 neurons, as well as for other interconnected cell types, in signaling errors and learning across cortical modalities.