13, 14 These initial findings have been subsequently reinforced by neuroimaging studies reporting compromised structural integrity and aberrant activation of the auditory cortices in patients with schizophrenia. 12 Electrophysiology studies were the first to report an association between schizophrenia and abnormalities in event related potentials relating to auditory perception and gating. 10, 11 However, patients with schizophrenia show “bottom-up” deficits in auditory processing despite normal auditory acuity. 5, 6 Models that focus on “top-down” processes attribute auditory hallucinations to the assignment of aberrant salience to external sounds 7, 8 or internally generated speech 9 and emphasize dysconnectivity in the corresponding functional networks. 3, 4 Therefore, improved understanding of the biological origins of auditory hallucinations is essential for reducing their contribution to the disease burden of schizophrenia.Ĭurrent theoretical accounts of auditory hallucinations implicate both “top-down” and “bottom-up” mechanisms. 2 Moreover, they are treatment-resistance in 10% of first-episode patients and this proportion increases to 30% over follow-up periods of up to 10 years. 1 Auditory hallucinations are typically distressing and increase the risk of suicidal and aggressive behavior. They are common in neuropsychiatric disorders, and particularly in schizophrenia, where they afflict more than 80% of patients. These findings suggest that the predisposition to auditory hallucinations is likely to be predicated on abnormalities in the functional organization of the auditory cortex and which may serve as a biomarker for the early identification of vulnerable individuals.Īuditory hallucinations are sensory experiences of sound in the absence of a corresponding external source. Compared to healthy participants, patients showed abnormally increased activation and altered tonotopic organization of the auditory cortex during a purely perceptual task, which involved passive listening to tones across a range of frequencies (88–8000 Hz). Tonotopy is a fundamental feature of the functional organization of the auditory cortex that is established very early in development and predates the onset of symptoms by decades.

To address this knowledge gap, we capitalized on the increased spatial resolution afforded by ultra-high field imaging at 7 Tesla to investigate the tonotopic organization of the auditory cortex in patients with schizophrenia with a history of recurrent hallucinations. Despite significant progress, it is still unclear whether auditory hallucinations arise from abnormalities in primary sensory processing or whether they represent failures of higher-order functions. Auditory hallucinations are among the most prevalent and most distressing symptoms of schizophrenia.

Auditory hallucinations schizophrenia