What it is
The insular cortex has a central role in pain, interoception (the sense of the body's internal state) and feelings, yet its functional architecture and the causal electrophysiological relationships among its subregions have remained poorly understood. The authors combined intracranial electrical stimulation and task-based electroencephalography recordings with connectivity mapping within a cytoarchitectonic atlas of the human insula in 87 participants implanted with intracranial electrodes, and identified an architecture of four distinct regions: a dorsal-posterior region encoding nociceptive, thermoceptive and somatosensory signals organized by body part; a ventral-posterior region with access to somatic information across multiple body parts; a mid-anterior region associated with visceral sensations and anxiety states; and an anterior-polar region, largely silent to direct stimulation yet robustly active during salience detection and change of action mode. This anterior region, strongly connected with the prefrontal cortex including the anterior cingulate cortex, exerts strong and direct influence over the other insular regions while receiving less strong, indirect input from them, which the authors read as an electrophysiological pathway for the cognitive modulation of pain and bodily perception. The findings link the insula's cytoarchitecture to directed and asymmetric electrophysiological interactions, with mechanistic implications for how cognition modulates pain and interoceptive experience.
Why it matters
In 87 people with brain electrodes, the insula split into four regions, the front one influencing the rest: by the authors' reading, a pathway for cognition to modulate pain. The insula has a central role in pain, interoception and feelings, but how its parts are organized and influence one another had been poorly understood. Here a dorsal-posterior region encodes nociceptive, thermal and somatosensory signals by body part, a ventral-posterior region has access to sensation across multiple body parts, a mid-anterior region is tied to visceral sensations and anxiety, and an anterior-polar region, largely silent when stimulated directly but active during salience detection, exerts strong, direct influence on the others while receiving weaker, indirect input back.
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Filed underFunctional Brain Connectivity Studies, Neural and Behavioral Psychology Studies, Psychosomatic Disorders and Their Treatments
