What Happens in the Brain When a Person with Schizophrenia “Hears Voices”?
October 3, 2024
Introduction:
(Eurekalert) Auditory hallucinations are likely the result of abnormalities in two brain processes: a “broken” corollary discharge that fails to suppress self-generated sounds, and a “noisy” efference copy that makes the brain hear these sounds more intensely than it should. That is the conclusion of a new study published October 3rd in the open-access journal PLOS Biology by Xing Tian, of New York University Shanghai, China, and colleagues.
Patients with certain mental disorders, including schizophrenia, often hear voices in the absence of sound. Patients may fail to distinguish between their own thoughts and external voices, resulting in a reduced ability to recognize thoughts as self-generated. In the new study, researchers carried out electroencephalogram (EEG) experiments measuring the brain waves of twenty patients diagnosed with schizophrenia with auditory hallucinations and twenty patients diagnosed with schizophrenia who had never experienced such hallucinations.
In general, when people are preparing to speak, their brains send a signal known as “corollary discharge” that suppresses the sound of their own voice. However, the new study showed that when patients with auditory hallucinations were preparing to speak a syllable, their brains not only failed to suppress these internal sounds, but had an enhanced “efference copy” response to internal sounds other than the planned syllable.
The authors conclude that impairments in these two processes likely contribute to auditory hallucinations and that targeting them in the future could lead to new treatments for such hallucinations.
The authors add, “People who suffer from auditory hallucinations can ‘hear’ sounds without external stimuli. A new study suggests that impaired functional connections between motor and auditory systems in the brain mediate the loss of ability to distinguish fancy from reality.
Read more here:
https://www.eurekalert.org/news-releases/1059425
caltrek’s comment: A psychologist named Julian Jaynes argued that such hearing of voices was more common than most of us believe, and that even otherwise “healthy” persons sometimes hear such voices. The mechanism that he thought was at play was somewhat different than that described in the article above. Religious literature is full of folks that have experienced such voices. Unlike the stereotype, the voices are not always malevolent in nature.
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