Static and Dynamic Autonomic Response with Increasing Nausea Perception

Background—Nausea is a commonly occurring symptom typified by epigastric discomfort with urge to vomit. The relationship between autonomic nervous system (ANS) outflow and increasing nausea perception is not fully understood. Methods—Our study employed a nauseogenic visual stimulus (horizontally translating stripes) while 17 female subjects freely rated transitions in nausea level and autonomic outflow was measured (heart rate, HR, heart rate variability, HRV, skin conductance response, SCR, respiratory rate). We also adopted a recent approach to continuous high frequency (HF) HRV estimation to evaluate dynamic cardiovagal modulation. Results—HR increased from baseline for all increasing nausea transitions, especially transition to strong nausea (15.0±11.4 bpm), but decreased (−6.6±4.6 bpm) once the visual stimulus ceased. SCR also increased for all increasing nausea transitions, especially transition to strong nausea (1.76±1.68 μS), but continued to increase (0.52 ± 0.65 μS) once visual stimulation ceased. LF/HF HRV increased following transition to moderate (1.54±2.11 a.u.) and strong (2.57±3.49 a.u.) nausea, suggesting a sympathetic shift in sympathovagal balance. However, dynamic HF HRV suggested that bursts of cardiovagal modulation precede transitions to higher nausea, perhaps influencing subjects to rate higher levels of nausea. No significant change in respiration rate was found. Conclusions—Our results suggest that increasing nausea perception is associated with both increased sympathetic and decreased parasympathetic ANS modulation. These findings corroborate past ANS studies of nausea, applying percept-linked analyses and dynamic estimation of cardiovagal modulation in response to nausea.National Institutes of Health (U.S.) (Grant R01-HL084502)National Institutes of Health (U.S.) (Grant R01-DA015644)National Institutes of Health (U.S.) (Grant DP1-OD003646)National Institutes of Health (U.S.) (Grant K01-AT002166)National Institutes of Health (U.S.) (Grant P01-AT002048)National Institutes of Health (U.S.) (Grant F05-AT003770)National Institutes of Health (U.S.) (Grant K23-DK069614)National Center for Research Resources (U.S.) (P41RR14075)National Center for Research Resources (U.S.) (CRC 1 UL1 RR025758-01)Mental Illness and Neuroscience Discovery (MIND) InstituteInternational Foundation of Functional Gastrointestinal DisordersInstitute of Information Technology Advancement (South Korea)Institute of Information Technology Advancement (South Korea) (Korea IITA- 2008-(C1090-0801-0002)

Dynamic cardiovagal response to motion sickness: A point-process heart rate variability study

A visual display of stripes was used to examine cardiovagal response to motion sickness. Heart rate variability (HRV) was investigated using dynamic methods to discern instantaneous fluctuations in reaction to stimulus and perception-based events. A novel point process adaptive recursive algorithm was applied to the R-R series to compute instantaneous heart rate, HRV, and high frequency (HF) power as a marker of vagal activity. Results show interesting dynamic trends in each of the considered subjects. HF power averaged across ten subjects indicates a significant decrease 20s to 60s following the transition from "no nausea" to "mild." Conversely, right before "strong" nausea, the group average shows a transient trending increase in HF power. Findings confirm gradual sympathetic activation with increasing nausea, and further evidence transitory increases in vagal tone before flushes of strong nausea.National Institutes of Health (U.S.) (R01- HL084502)National Institutes of Health (U.S.) (R01-DA015644)National Institutes of Health (U.S.) (DP1-OD003646)National Institutes of Health (U.S.) (K01-AT002166)National Institutes of Health (U.S.) (P01-AT002048)National Institutes of Health (U.S.) (F05-AT003770)National Institutes of Health (U.S.) (K23-DK069614)National Center for Complementary and Alternative Medicine (U.S.) (P41RR14075; CRC 1 UL1 RR025758- 01)Mental Illness and Neuroscience Discovery (MIND) InstituteInternational Foundation for Functional Gastrointestinal DisordersInstitute of Information Technology Advancement (South Korea) (IITA-2008- (C1090-0801-0002)

The brain circuitry underlying the temporal evolution of nausea in humans. Cerebral cortex

Nausea is a universal human experience. It evolves slowly over time, and brain mechanisms underlying this evolution are not well understood. Our functional magnetic resonance imaging (fMRI) approach evaluated brain activity contributing to and arising from increasing motion sickness. Subjects rated transitions to increasing nausea, produced by visually induced vection within the fMRI environment. We evaluated parametrically increasing brain activity 1) precipitating increasing nausea and 2) following transition to stronger nausea. All subjects demonstrated visual stimulus--associated activation (P < 0.01) in primary and extrastriate visual cortices. In subjects experiencing motion sickness, increasing phasic activity preceding nausea was found in amygdala, putamen, and dorsal pons/locus ceruleus. Increasing sustained response following increased nausea was found in a broader network including insular, anterior cingulate, orbitofrontal, somatosensory and prefrontal cortices. Moreover, sustained anterior insula activation to strong nausea was correlated with midcingulate activation (r 5 0.87), suggesting a closer linkage between these specific regions within the brain circuitry subserving nausea perception. Thus, while phasic activation in fear conditioning and noradrenergic brainstem regions precipitates transition to strong nausea, sustained activation following this transition occurs in a broader interoceptive, limbic, somatosensory, and cognitive network, reflecting the multiple dimensions of this aversive commonly occurring symptom