Localization and responses of neurones in the parieto‐insular vestibular cortex of awake monkeys (Macaca fascicularis).

Abstract

SUMMARY1. In four Java monkeys (Macaca fascicularis) 152 vestibular neurones were recorded in the parietal cortex located in the upper bank of the lateral sulcus near the posterior end of the insula. We called this region parieto-insular vestibular cortex (PIVC). PIVC extends about 6-8 mm in the anterior-posterior direction from the posterior part of the insula into the retroinsular region (stereotaxic co-ordinates: anterior 4-12 mm, lateral 16-19 mm and vertical 3-6 mm).2. About two-thirds of the neurones recorded from this region responded to vestibular stimuli; the non-vestibular neurones responded predominantly to somatosensory stimulation of the neck and shoulder region. The PIVC area is a polysensory field, since almost all vestibular neurones were also activated by somatosensory and visual stimuli. Large-field optokinetic stimulation was the most effective visual stimulus.3. With vestibular stimuli, responses to angular acceleration were dominant; steady tilt in darkness rarely led to any change in neuronal spontaneous activity. Of sixty-four neurones tested by rotation in more than one plane, fifty-four responded to excitation of semicircular canal receptors aroused by rotation in more than one of the three experimental planes (roll, yaw, pitch 0. -J. GR USSER, M. PA USE AND U. SCHREITER rotational planes. For different units the relative sensitivity to rotation in each of the three planes also differed. We concluded from this observation that different PIVC units had different optimum sensitivity planes for rotation with respect to the head co-ordinates, whereby all possible planes are represented.

Bodily ownership and self-location: Components of bodily self-consciousness

“…A vestibular contribution to self-location seems of relevance here because the sensations of elevation and floating reported by the participants of Ionta et al's study are close to vestibular illusions reported by patients with damage to the otolithic vestibular system and the central vestibular structures (Schilder, 1935). Several regions of the TPJ located around the posterior end of the Sylvian fissure, such as the angular, supramarginal and superior temporal gyrus, and the regions located in the depth of the Sylvian fissure, such as the parietal operculum, insula and the retroinsular cortex, are strongly involved in vestibular processing (Chen, DeAngelis, & Angelaki, 2010;Grüsser, Pause, & Schreiter, 1990;Lopez, Blanke, & Mast, 2012). Lesions or seizures in the TPJ may alter the experience of self-location, such as during what are often called out-of-body experiences.…”

Body ownership and embodiment: Vestibular and multisensory mechanisms

“…Electrophysiological recordings in macaque, squirrel and marmoset monkeys showed that many neurons are driven by vestibular inputs in a region that Grüsser and colleagues called ''parieto-insular vestibular cortex'' (PIVC) [61,[63][64][65]67]. Anatomically, this region is located in the depth of the Sylvian fissure at the level of the posterior insula extending posteriorly to the retroinsular cortex as well as anteriorly to the parietal operculum.…”

Visual-vestibular processing in the human Sylvian fissure

“…This information is of critical relevance for guiding locomotion and for process- There is accumulating evidence that the potential hub of the cortical vestibular network is located in a region including the posterior part of the Sylvian fissure (also called lateral sulcus), perisylvian cortex, and the posterior insula. At this site, functional imaging studies in humans found activation during vestibular stimulation (Bense et al 2001;Dieterich et al 2003;Eickhoff et al 2006;Fasold et al 2002;Lobel et al 1998) and labeled it the parieto-insular vestibular cortex (PIVC), following terminology in the primate brain (Akbarian et al 1988;Chen et al 2010;Grüsser et al 1990; Shinder and Newlands 2014).However, the vestibular network in the posterior Sylvian fissure is likely more complex and might include at least one additional area, named posterior insular cortex (PIC), that responds to vestibular stimuli as well as to visual object motion and potentially serves as a site of multisensory integration .The anatomical and functional relationship between PIC and PIVC is still unclear, because both areas have not yet been investigated in the same participant. Therefore, in this study we aimed to define and compare the regions known as PIVC and PIC directly in the same participants.…”