An ontogenetic role for Broca's and related speech areas in schizophrenic auditory hallucinations? Evidence from sulcal pits analysis.

The pathogenesis of auditory verbal hallucinations (AVH), a core symptom of schizophrenia, is unknown, but there is increasing interest in the possibility that it involves brain structural changes. We used a novel whole brain structural imaging technique, sulcal pits analysis, to measure different parameters of sulcal pits, the deepest points in each fold of the cerebral cortex, in 24 schizophrenia patients with continuous or near-continuous hallucinations (AVH-frequent) and 22 matched patients who had never experienced AVH (AVH-never). A matched group of 58 healthy controls (HC) were also examined. In comparison to the AVH-never patients, the AVH-frequent patients exhibited increased depth of sulcal pits in a region of the left inferior frontal cortex and anterior insula, overlapping with Broca's Area and Brodmann Area 47. A nearly identical result emerged in the comparison between AVH-frequent patients and the HC. These findings suggest that a neurodevelopmentally stable brain structural alteration may contribute to the manifestation of AVH in individuals later diagnosed with schizophrenia. This finding also has relevance for theoretical approaches to AVH, a leading example of which relates them to inner speech.