NRG1 and schizophrenia: Among various neuregulin-1 receptors, the ErbB4 receptor, whose gene also confers schizophrenia susceptibility [173, 174], is enriched in GABA neurons, particularly in PV-positive cells [175, 176] where it facilitates GABA release [176], possibly mediating neuregulin-1 enhancement of gamma oscillations [177].