Functional mapping of the human insula: Data from electrical stimulations

Area of Science:

• Neuroscience
• Functional Neurosurgery
• Epileptology

Background:

• The insular cortex plays a crucial role in integrating sensory, emotional, and cognitive information.
• Understanding insular cortex function is vital for interpreting insular seizures and predicting surgical outcomes.
• Stereo-electro-encephalography (SEEG) allows direct electrical stimulation for functional mapping.

Purpose of the Study:

• To provide a functional map of the insular cortex using electrical stimulation.
• To correlate stimulation-evoked responses with specific insular regions.
• To enhance understanding of insular cortex physiology and semiology of insular seizures.

Main Methods:

• Electrical stimulation of the insula during SEEG in patients.
• Systematic recording and analysis of evoked ictal symptoms and functional responses.
• Review of previous literature on insular cortex stimulation.

Main Results:

• Somatosensory and visceral responses were the most frequently evoked by insula stimulation.
• Auditory, vestibular, speech, gustato-olfactory, and motor responses were also observed with decreasing frequency.
• A posterior-to-anterior functional organization was suggested, with somatosensory/pain in the posterior and visceral in the anterior insula.
• Significant spatial overlap was noted between representations of different response types.

Conclusions:

• Electrical stimulation during SEEG effectively maps insular cortex functions.
• The insular cortex exhibits a multimodal representation, supporting its role in integrating diverse inputs.
• Findings improve understanding of insular physiology, seizure semiology, and potential post-surgical deficits.