How the insula speaks to the heart: Cardiac responses to insular stimulation in humans

Abstract

Despite numerous studies suggesting the role of insular cortex in the control of autonomic activity, the exact location of cardiac motor regions remains controversial. We provide here a functional mapping of autonomic cardiac responses to intracortical stimulations of the human insula. The cardiac effects of 100 insular electrical stimulations into 47 epileptic patients were divided into tachycardia, bradycardia, and no cardiac response according to the magnitude of RR interval (RRI) reactivity. Sympathetic (low frequency, LF, and low to high frequency powers ratio, LF/HF ratio) and parasympathetic (high frequency power, HF) reactivity were studied using RRI analysis. Bradycardia was induced by 26 stimulations (26%) and tachycardia by 21 stimulations (21%). Right and left insular stimulations induced as often a bradycardia as a tachycardia. Tachycardia was accompanied by an increase in LF/HF ratio, suggesting an increase in sympathetic tone; while bradycardia seemed accompanied by an increase of parasympathetic tone reflected by an increase in HF. There was some left/right asymmetry in insular subregions where increased or decreased heart rates were produced after stimulation. However, spatial distribution of tachycardia responses predominated in the posterior insula, whereas bradycardia sites were more anterior in the median part of the insula. These findings seemed to indicate a posterior predominance of sympathetic control in the insula, whichever the side; whereas the parasympathetic control seemed more anterior. Dysfunction of these regions should be considered when modifications of cardiac activity occur during epileptic seizures and in cardiovascular diseases.

Cardiac‐Related Pulsatility in the Insula Is Directly Associated With Middle Cerebral Artery Pulsatility Index

“…It is interesting that DBP was associated with insular cardiac‐related pulsatility, which is in line with lesion studies . Moreover, cardiac regulation is lateralized, wherein the right insula is linked to sympathetic control while the left insula is linked to parasympathetic control, although such findings continue to be debated . Our results revealed higher pulsatility in the left insula compared with the right, and a left insular pulsatility association with DBP.…”

Mapping the Insula with Stereo‐Electroencephalography: The Emergence of Semiology in Insula Lobe Seizures

“…Although tachycardia was not reported as an aura, it was a consistent intrainsular manifestation in this series, and stimulation studies confirm autonomic cardiac responses from insular cortex. 39 The nature of the reflex component also correlates to insula functional subdivision. As the insula is a multimodal area involved in processing of various sensory stimuli, insulo-opercular seizures may manifest as eating-, audiogenic-, and somatosensoryevoked reflex seizures.…”

Can increased interoception explain exercise-induced benefits on brain function and cognitive performance?

“…Third, the anterior cingulate cortex is closely related to the insula, being considered an output region for the interoceptive system (Medford & Critchley, 2010). Fourth, the insular cortex is considered a hemodynamic control center, therefore having a key role in the brainheart communication, closely related to physiological regulation during exercise (Chouchou et al, 2019;Nagai, Hoshide, & Kario, 2010;Oppenheimer, Gelb, Girvin, & Hachinski, 1992;Ruggiero, Mraovitch, Granata, Anwar, & Reis, 1987). Last, but not least, these hubs are connected with the dorsolateral prefrontal cortex, which presents a pivotal role in executive functioning (Bush, Luu, & Posner, 2000;Carter, Botvinick, & Cohen, 1999;Sridharan, Levitin, & Menon, 2008).…”