Corticovestibular interactions: anatomy, electrophysiology, and functional considerations

Abstract

This review summarizes anatomical and electrophysiological observations related to corticovestibular interactions as a step toward understanding their possible functions. Vestibular information is represented in at least three distinct regions of the cerebral cortex in cats and monkeys: the parietal and somatosensory cortex and the parietoinsular vestibular cortex. In addition, vestibular-related signals are found in more extensive regions, including the motor and premotor regions and frontal eye fields. Most of these regions also project directly to the vestibular nuclei. In monkeys, at least six cortical regions have been identified, including the motor, somatosensory, parietal and temporal areas. Most of these regions receive vestibular projections via the thalamus. Most neurons in those cortical areas respond to head velocity and receive converging vestibular, visual and somatosensory input. Electrical stimulation of some of these cortical areas in anesthetized cats influences the activity of many vestibular nuclear neurons including those projecting to the spinal cord. Lesions of the parietal vestibular regions impair the vestibulo-ocular reflex (VOR) and visual suppression of the VOR as well as vestibular-related cognitive functions such as spatial perception and memory in human subjects. Diffuse cortical damage also results in similar impairment of the VOR and suppression of the VOR and possibly the vestibulo-collic reflex. Such impairments after cortical lesions may well be due in part to interruption of cortico-vestibular connections. Future studies in alert animals should focus on the role of different cortical regions projecting to the vestibular nuclei, specifically on how each affects the processing of vestibular signals that mediate vestibulo-motor reflexes and that are used for vestibular related cognitive processes.

Body ownership and embodiment: Vestibular and multisensory mechanisms

“…Several areas that receive vestibular cues have been described in non-human primate cortex and human cortex (for reviews see [9,25,54,67,87,97]). 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].…”

Latency of vestibular responses of pursuit neurons in the caudal frontal eye fields to whole body rotation

“…2D) were induced by the trisynaptic pathway from the labyrinth through the vestibular nuclei and the thalamic regions (Fukushima 1997 for a review) for the following reasons. Ebata et al (2004) reported vestibular evoked, presumably trisynaptic, potentials in the fundus of the arcuate sulcus in anesthetized monkeys following electrical stimulation of the labyrinth at latencies of 4.8-6.3 ms but with peak responses at 15 ms ( Fig.…”

Squirrel Monkeys and Space Motion Sickness

“…Three kinds of tracers were injected into the vestibular nuclei, and retrograde labeling into the cortex was studied after an appropriate interval (48 h for WGA-HRP and 14 d for Fast blue and Rhodamine). The seven vestibular cortices are (1) parieto-insular vestibular cortex (PIVC), including Ri (retroinsular cortex) and Ig (granular insular cortex); (2) area 3aV; (3) parieto-temporal association cortex (anterior part of area 7 (7 ant), probably corresponding to area 2v of the M. mulatta at the lateral end of the intraparietal sulcus; (4) temporal cortex adjacent to Ri (temporal lobe; T3); (5) area 6a; and (6) area 23 [59,60]. This observation established a direct projection from the cortex to the vestibular nuclei.…”

“…All these cortical areas received afferents from the bilateral vestibular nuclei, with contralateral dominance, probably through the thalamus [63][64][65][66][67]. Among the seven vestibular cortices, PIVC, area 3aV, and area 2v form an "inner cortical vestibular circuit," which organizes information of the head and the vestibular system after receiving separate somatosensory, proprioceptive (SI), and optokinetic signals [59].…”