Neuregulin has been shown to be involved in the myelination of central nervous system (CNS) axons. There exist at least two modes of myelination within the CNS—one that is independent of neuronal activity and another that is promoted by the activation of NMDA receptors by glutamate on oligodendrocytes. Neuregulin is involved in the "switching" of oligodendrocytes from the mode of myelination that is independent of neuronal activity to the mode that is dependent upon glutamate binding to NMDA receptors. It is thought that Neuregulin 1 found on axons of CNS neurons interacts with its receptor, ErbB4, to promote the myelination of that axon, and any disruption in this signaling contributes to decreased myelination. Since Neuregulin 1 promotes myelination and is decreased in schizophrenic patients, along with the finding that schizophrenic patients experience white matter deficits, mutations within Neuregulin 1 may underlie cognitive deficits associated with lower white matter integrity, especially within frontotemporal connections.