PPP1R1B and stroke disorder: Since, SOM expression was also absent in spiny neurons, as assessed by co-staining between SOM and the spiny neuronal marker DARPP-32 (Fig. 4f), we then investigated the possibility that after stroke, SOM-negative interneurons had acquired SOM expression by performing co-staining with SOM and parvalbumin (PV), calretinin (Cr) and Choline acetyltransferase (ChAT).