Insular Cortex-Biology and Its Role in Psychiatric Disorders: A Narrative Review

Area of Science:

• Neuroscience
• Psychiatry

Background:

• The insular cortex integrates sensory, emotional, and cognitive information, acting as a key hub in the brain's salience network.
• Its anterior (AIC) and posterior (PIC) regions specialize in emotional awareness/interoception and somatosensory processing, respectively.

Purpose of the Study:

• To explore the insular cortex's role in psychiatric pathophysiology.
• To review evidence linking insular structure and connectivity alterations to mental disorders.

Main Methods:

• Review of existing literature on insular cortex structure, connectivity, and function in psychiatric conditions.
• Analysis of findings in schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorders.

Main Results:

• Reduced insular volume, particularly left-sided, correlates with hallucinations and cognitive deficits in schizophrenia.
• Anterior insula (AIC) volume loss and altered connectivity are observed in bipolar and major depressive disorders, impacting affect regulation.
• Functional hyperactivity of the insula is noted in anxiety disorders, though structural findings are inconsistent.

Conclusions:

• The insular cortex plays a significant role in the pathophysiology of various mental disorders.
• Insular cortex alterations represent potential targets for future diagnostic and therapeutic strategies in psychiatry.