Cortical Correlates of the Simulated Viewpoint Oscillation Advantage for Vection

Abstract

Behavioural studies have consistently found stronger vection responses for oscillating, compared to smooth/constant, patterns of radial flow (the simulated viewpoint oscillation advantage for vection). Traditional accounts predict that simulated viewpoint oscillation should impair vection by increasing visual–vestibular conflicts in stationary observers (as this visual oscillation simulates self-accelerations that should strongly stimulate the vestibular apparatus). However, support for increased vestibular activity during accelerating vection has been mixed in the brain imaging literature. This fMRI study examined BOLD activity in visual (cingulate sulcus visual area — CSv; medial temporal complex — MT+; V6; precuneus motion area — PcM) and vestibular regions (parieto-insular vestibular cortex — PIVC/posterior insular cortex — PIC; ventral intraparietal region — VIP) when stationary observers were exposed to vection-inducing optic flow (i.e., globally coherent oscillating and smooth self-motion displays) as well as two suitable control displays. In line with earlier studies in which no vection occurred, CSv and PIVC/PIC both showed significantly increased BOLD activity during oscillating global motion compared to the other motion conditions (although this effect was found for fewer subjects in PIVC/PIC). The increase in BOLD activity in PIVC/PIC during prolonged exposure to the oscillating (compared to smooth) patterns of global optical flow appears consistent with vestibular facilitation.

Multisensory Interactions in Virtual Reality: Optic Flow Reduces Vestibular Sensitivity, but Only for Congruent Planes of Motion

“…Several studies report that activity in the parieto-insular vestibular cortex (PIVC) is decreased when experiencing vection in the absence of vestibular cues (Brandt et al, 1998;Kleinschmidt et al, 2002). However, increased activity in PIVC has also been described (Kirollos et al, 2017;Uesaki and Ashida, 2015). It is possible that differences in optic flow stimuli account for these apparently discrepant findings:…”

“…while constant velocity stimuli across one axis were used in studies describing decreased PIVC activity (Brandt et al, 1998;Kleinschmidt et al, 2002), much more complex optic flows were used in studies reporting increased PIVC activity (Kirollos et al, 2017;Uesaki and Ashida, 2015). Thus, the effects of vection and optic flow on PIVC are not yet entirely clear.…”

A virtual reality study investigating the train illusion

“…Although various researchers have investigated neurophysiological (e.g. [27,62,63], see [19] for a review), postural (e.g. [64][65][66]) and behavioural (e.g.…”

A Virtual Reality Study Investigating the Train Illusion

“…Although various researchers have investigated neurophysiological (e.g., Kirollos et al, 2017;Palmisano, Barry, et al, 2016, see Berti & Keshavarz, 2020, for a review), postural (e.g., Mursic et al, 2017;Tanahashi et al, 2007;Thurrell & Bronstein, 2002), and behavioural (e.g., Palmisano & Gillam, 1998) correlates to vection, there appears to be a lack of studies investigating responses from the autonomic nervous system that might correlate to the participants' experience of vection. In contrast, psychophysiological measures of Cybersickness (CS), visually-induced motion sickness (VIMS) and Presence are employed more commonly, where researchers have identified physiological indices associated with the (de)activation of the (para)sympathetic nervous system that correlate to participants' experience of CS, VIMS, or Presence (see Caserman et al, 2021;Farmer et al, 2014;Grassini & Laumann, 2020, for reviews).…”