Motion sickness increases functional connectivity between visual motion and nausea-associated brain regions

Abstract

The brain networks supporting nausea not yet understood. We previously found that while visual stimulation activated primary (V1) and extrastriate visual cortices (MT+/V5, coding for visual motion), increasing nausea was associated with increasing sustained activation in several brain areas, with significant co-activation for anterior insula (aIns) and mid-cingulate (MCC) cortices. Here, we hypothesized that motion sickness also alters functional connectivity between visual motion and previously identified nausea-processing brain regions. Subjects prone to motion sickness and controls completed a motion sickness provocation task during fMRI/ECG acquisition. We studied changes in connectivity between visual processing areas activated by the stimulus (MT+/V5, V1), right aIns and MCC when comparing rest (BASELINE) to peak nausea state (NAUSEA). Compared to BASELINE, NAUSEA reduced connectivity between right and left V1 and increased connectivity between right MT+/V5 and aIns and between left MT+/V5 and MCC. Additionally, the change in MT+/V5 to insula connectivity was significantly associated with a change in sympathovagal balance, assessed by heart rate variability analysis. No state-related connectivity changes were noted for the control group. Increased connectivity between a visual motion processing region and nausea/salience brain regions may reflect increased transfer of visual/vestibular mismatch information to brain regions supporting nausea perception and autonomic processing. We conclude that vection-induced nausea increases connectivity between nausea-processing regions and those activated by the nauseogenic stimulus. This enhanced low-frequency coupling may support continual, slowly evolving nausea perception and shifts toward sympathetic dominance. Disengaging this coupling may be a target for biobehavioral interventions aimed at reducing motion sickness severity.

Functional brain networks and neuroanatomy underpinning nausea severity can predict nausea susceptibility using machine learning

“…; Toschi et al . ). In particular, we identified a network which increased in strength (functional connectivity/information transfer) with increasing nausea severity, which encompassed the anterior, mid‐ and posterior cingulate cortices, both sides of the thalamus, right caudate nucleus and nucleus accumbens.…”

“…; Toschi et al . ), although their co‐relationship to autonomic neurophysiology seems salient and will be elaborated on below.…”

“…; Toschi et al . ). Furthermore, neuroanatomical differences in white matter tracts have also been associated with increased nausea susceptibility (Napadow et al .…”

“…), or pairwise connectivity between two areas (Toschi et al . ). Given the complexity of the sensation of nausea, it seems likely that the physiological and interoceptive components of a nauseous experience are a result of many brain areas interacting in synchrony.…”

“…; Toschi et al . ), they remain relatively scarce in comparison to those evaluating other aspects of GI sensation, such as visceral pain (Ruffle et al . ).…”