Reality of auditory verbal hallucinations

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Psychosis, characterized by delusions and hallucinations, significantly distorts reality perception.
• The precise neural underpinnings of these altered reality perceptions remain largely elusive.
• Auditory verbal hallucinations (AVH) are a hallmark symptom in conditions like schizophrenia.

Purpose of the Study:

• To investigate the neuronal correlates of subjective reality in AVH.
• To identify specific brain regions and their interactions associated with the perceived realness of AVH.
• To explore the relationship between brain activity and the intensity of experienced reality in AVH.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to study 11 participants with schizophrenia or schizoaffective disorder.
• Participants rated the subjective reality of their AVH during fMRI scanning.
• Analysis focused on correlating hallucination-related brain activation and functional connectivity with subjective reality ratings.

Main Results:

• A strong, specific correlation was found between the subjective reality of AVH and activation strength in the inferior frontal gyri (IFG), including Broca's area.
• The perceived reality of AVH was dependent on functional coupling between the IFG, ventral striatum, auditory cortex, right posterior temporal lobe, and cingulate cortex.
• These findings highlight the involvement of speech comprehension, sensory processing, salience detection, and self-monitoring networks.

Conclusions:

• The subjective experience of reality in AVH is linked to motor aspects of speech comprehension.
• Brain regions involved in sensory processing, salience detection, self-monitoring, and agency contribute to AVH reality perception.
• Understanding these neural mechanisms offers insights into psychosis and potential therapeutic targets.