GAP43 and schizophrenia: A study using real-time quantitative PCR to measure activity-dependent gene levels in cerebellar cortical glutamatergic neurons showed that GAP43 mRNA levels were significantly increased in schizophrenia patients, proposing that glutamatergic neurons may be hyperactive in the cerebellar cortex of schizophrenia patients, resulting in short-term plasticity abnormalities [17].