Insulo-opercular cortex generates oroalimentary automatisms in temporal seizures

Area of Science:

• Neuroscience
• Epileptology
• Clinical Neurology

Background:

• Oroalimentary automatisms (OAAs) are complex, stereotyped movements resembling normal feeding behaviors observed during epileptic seizures.
• While common in temporal lobe epilepsy, the precise anatomofunctional mechanisms underlying OAAs remain incompletely understood.
• Presurgical intracerebral recordings offer a unique opportunity to investigate the neural correlates of OAAs.

Purpose of the Study:

• To investigate the spatio-temporal relationship between ictal brain activity and the occurrence of oroalimentary automatisms (OAAs) in patients with temporal lobe epilepsy.
• To identify the specific brain regions and network dynamics associated with OAA generation during seizures.

Main Methods:

• Retrospective analysis of stereoelectroencephalography (SEEG) data from patients with medically intractable medial temporal lobe epilepsy.
• Correlation of SEEG-recorded ictal activity with observed oroalimentary automatisms, including latency measurements.
• Coherence analysis of neural oscillations in temporal and insulo-opercular regions preceding OAA onset.

Main Results:

• Analysis of 115 seizures in 15 patients revealed that 69 seizures featured overt OAAs.
• Ictal involvement of the insulo-opercular cortex was consistently associated with OAA occurrence.
• A linear correlation was observed between OAA onset and the onset of ictal oscillatory activity in the insulo-opercular cortex.
• Increased theta coherence between mediobasal-temporal structures and the insulo-opercular cortex, as well as between bilateral insulo-opercular regions, preceded OAA onset.

Conclusions:

• The generation of oroalimentary automatisms in medial temporal lobe epilepsy is critically dependent on the insulo-opercular cortex.
• Temporal-insulo-opercular theta coherence plays a key role in establishing a synchronous state that drives rhythmic outputs from the cortical masticatory area, leading to OAAs.