Auditory hallucinations and smaller superior temporal gyral volume in schizophrenia.

Recent neuropathologic investigations in schizophrenia report smaller volume of medial temporal lobe structures. These findings are confirmed by preliminary magnetic resonance imaging (MRI) studies. Direct stimulation of lateral temporal lobe structures in the region of the superior temporal gyrus provokes hallucinations. The authors' MRI study of young schizophrenic patients demonstrates smaller volume of the superior temporal gyrus (an auditory association area) and of the left amygdala. Smaller size of the left superior temporal gyrus and left amygdala is not accounted for by smaller size of the overall brain or temporal lobe. Shrinkage of the left superior temporal gyrus is strongly and selectively correlated with severity of auditory hallucinations.