People with schizophrenia who experience auditory hallucinations have greater activation in specific areas of the auditory cortex in response to sound frequencies. The mapping of sound frequency in the auditory cortex is scrambled in those with schizophrenia, suggesting a disruption in the normal processes for organized sound representation in the brain. As the tonotopic map is established during infancy and remains stable throughout life, the findings suggest vulnerability for auditory hallucinations is linked to defects in the organization of the auditory system during infantile development. This precedes speech development and the onset of psychiatric symptoms.
