Cardiovascular effects of human insular cortex stimulation

TLDR

Cardiac control is represented in the left insular cortex of rats, with left‑sided dominance for sympathetic effects, but it is unknown whether humans share this representation. The study stimulated the insular cortex intraoperatively in five epilepsy patients before temporal lobectomy. Stimulation of the left insular cortex produced bradycardia and depressor responses more often than tachycardia and pressor effects, whereas the right insular cortex produced the opposite pattern, indicating right‑sided dominance for sympathetic effects in humans and demonstrating lateralized cardiovascular responses during insular stimulation.

Abstract

Recent investigations indicate a site of cardiac representation within the left insular cortex of the rat. Moreover, the results of lesion studies suggest left-sided insular dominance for sympathetic cardiovascular effects. It is unclear whether similar representation exists within the human insular cortex. Five epileptic patients underwent intraoperative insular stimulation prior to temporal lobectomy for seizure control. On stimulation of the left insular cortex, bradycardia and depressor responses were more frequently produced than tachycardia and pressor effects (<i>p</i> &lt; 0.005). The converse applied for the right insular cortex. We believe this to be the first demonstration of cardiovascular changes elicitable during insular stimulation in humans, and of lateralization of such responses for a cortical site. In humans, unlike the rat, there appears to be right-sided dominance for sympathetic effects. These findings may be of relevance in predicting the autonomie effects of stroke in humans and in the explanation of sudden unexpected epileptic death.