PVALB and schizophrenia: In the hypoglutamate state, NMDA receptor signaling on the parvalbumin (PV)‐positive GABA interneurons is decreased in the cortex and hippocampus.46 PV‐positive GABA interneurons play a key role in cognitive function through the production of neural oscillation, especially gamma oscillation.47 Moreover, a significantly low level of gamma oscillation during cognitive tasks is reported in patients with schizophrenia.48 Thus, the clinical characterization of gamma oscillation could be a promising biomarker.