Cognitive and neural processes in non-clinical auditory hallucinations
BACKGROUND: The nosological status of auditory hallucinations in non-clinical samples is unclear. AIMS: To investigate the functional neural basis of non-clinical hallucinations. METHOD: After selection from 1206 people, 68 participants of high, medium and low hallucination proneness completed a task designed to elicit verbal hallucinatory phenomena under conditions of stimulus degradation. Eight subjects who reported hearing a voice when none was present repeated the task during functional imaging. RESULTS: During the signal detection task, the high hallucination-prone participants reported a voice to be present when it was not (false alarms) significantly more often than the average or low participants (P<0.03, d.f.=2). On functional magnetic resonance imaging, patterns of activation during these false alarms showed activation in the superior and middle temporal cortex (P<0.001). CONCLUSIONS: Auditory hallucinatory experiences reported in non-clinical samples appear to be mediated by similar patterns of cerebral activation as found during hallucinations in schizophrenia.