Neuropsychiatric disorders and functional localization

In this review, the functional localization of schizophrenia and depression, the two most common and representative psychiatric disorders, is described. Recent neuroimaging techniques have demonstrated various structural and functional brain abnormalities present in schizophrenia. These abnormalities, specifically focused in the frontal and temporal lobes, have functional relevance with positive symptoms of schizophrenia including auditory hallucinations and delusions. In addition, schizophrenia has been shown to have neural network abnormalities in the social brain, which subserves social and interpersonal relationships. Functional neuroimaging studies including SPECT, PET, NIRS and fMRI have repeatedly demonstrated hypofrontality in depression. It is important to note that such hypofrontality or functional impairment in depression may remain even after the clinical symptoms of depression have resolved. Longitudinal studies using various treatment strategies including pharmacotherapy, cognitive behavioral therapy and deep brain stimulation have widely contributed to understanding the mechanisms of functional recovery of the emotion-related neural network.