Abstract
The mechanism for auditory hallucinations of schizophrenia is not simple ; however, it seems important to investigate brain structures and functions related to psychotic symptoms. We will review findings of our structural and functional studies associated with auditory hallucinations. For the brain imaging study, the subregions of the lateral temporal lobe were measured by the manual drawing method. Compared to patients with no hallucinations, individuals with auditory hallucinations showed significantly reduced left superior temporal gyrus (STG) , left middle temporal gyrus and left inferior temporal gyrus. Therefore, it is suggested that left hemisphere gray matter volume reductions are dominant (especially STG) in patients with auditory hallucinations.
In the P50m study, there was a significant positive correlation between the left P50m gating ratio and the auditory hallucinatory score (ρ=0.44, p=0.04) . More specifically, patients with more severe auditory hallucinations showed more affected filtering functions to human voices. Furthermore, in the auditory steady state response (ASSR) study, there was a significant negative association between the left ASSR power to 80 Hz‐clicks and the severity of auditory hallucinations (ρ=‐0.50, p=0.04) . Thus, patients with 80 Hz‐ASSR deficits may have more severe auditory hallucinations.
Brain imaging and neurophysiological efforts will be important to understand the pathophysiology of schizophrenia.
