The ErbB4 mouse is a good model to study cerebellar defects associated with schizophrenia, in which an imbalance in the inhibitory Purkinje cells/excitatory granule cells takes place, altering cognitive processing in the cerebellum with downstream consequences for cortical cognitive function, a characteristic symptom of schizophrenic patients (Andreasen et al., 1999; Andreasen and Pierson, 2008). This evidence concerns the gene ERBB4 and schizophrenia.