Could Broken Brain Signals Be Causing Voices We Hear?

Auditory hallucinations, where individuals hear sounds without any external stimuli, are a complex phenomenon primarily associated with certain mental illnesses, particularly schizophrenia. Recent research published on October 3rd in the open-access journal PLOS Biology by Xing Tian and colleagues from New York University Shanghai sheds light on the underlying brain signals and processes that contribute to these experiences.

The Role of Brain Processes

The study reveals that auditory hallucinations may stem from defects in two critical brain processes, referred to as “brain signals”:

1. Corollary Discharge: This is a signal generated by the brain that typically dampens the perception of self-generated sounds, such as one’s own voice.
2. Efference Copy: This process amplifies internal sounds more intensely than usual, causing individuals to misinterpret their own thoughts as external voices.

Challenges for Patients

Patients experiencing auditory hallucinations often struggle to distinguish between their own thoughts and external voices. This difficulty can result in a decreased ability to recognize thoughts as self-generated, leading to confusion and distress.

Study Findings

In the recent study, researchers conducted electroencephalogram (EEG) studies on two groups of schizophrenia patients:

• Twenty patients with auditory hallucinations
• Twenty patients without auditory hallucinations

When individuals with auditory hallucinations prepared to speak, their brains failed to effectively suppress the sound of their own voice. Instead, these patients exhibited an intensified efference copy response to internal sounds that deviated from what they intended to express. This heightened reaction suggests a malfunction in brain processing, where the brain does not filter expected sounds correctly, potentially contributing to auditory hallucinations by amplifying internal sounds over external ones.

Implications for Treatment: Brain Signals

The authors of the study propose that abnormalities in the corollary discharge and efference copy processes are likely contributors to auditory hallucinations. Furthermore, targeting these defects in future treatments may pave the way for innovative therapeutic approaches to manage and alleviate these symptoms.

Conclusion: Bridging Fantasy, Reality, and Brain Signals

The research highlights the importance of understanding the functional connections between the brain’s motor and auditory systems. Moreover, poor connectivity can disrupt the ability to differentiate between self-generated thoughts and external sounds, blurring the line between fantasy and reality. These insights may lead to more effective treatment strategies for individuals grappling with auditory hallucinations, ultimately enhancing their quality of life.