Our finding of no change in PAK1 protein expression in the auditory cortex in combination with a recent study that found no change in PAK1 levels in the anterior cingulate cortex, but increased PAK1 levels in the dorsolateral prefrontal cortex, in subjects with schizophrenia, suggests there may be regional differences in disease-related PAK1 expression.[33] Alternatively, the significant correlation of within pair reductions in PAK1 and spinophilin raises the possibility that it is a subset of subjects with schizophrenia that have deficits in signaling via PAK1 to dendritic spines. This evidence concerns the gene PPP1R9B and schizophrenia.