The effects of constrained left versus right monocular viewing on the autonomic nervous system

Abstract

Asymmetrical activation of right and left hemispheres differentially influences the autonomic nervous system. Additionally, each hemisphere primarily receives retinocollicular projections from the contralateral eye. To learn if asymmetrical hemispheric activation induced by monocular viewing would influence relative pupillary size and respiratory hippus variability (RHV), a measure of parasympathetic activity, healthy participants had their left, right or neither eye patched. Pupillary sizes were then recorded with infrared pupillography. Pupillary dilation was significantly greater with left than right eye viewing. RHV, however, was not different between eye viewing conditions. These differences in pupil dilatation may have been caused by relatively greater activation of the right hemispheric-mediated sympathetic activity induced by left monocular viewing or relatively greater deactivation of the left hemispheric-mediated parasympathetic activity induced by right eye patching. The absence of an asymmetry in RHV, however, suggests that hemispheric asymmetry of sympathetic activation was primarily responsible for this ocular asymmetry of pupil dilation.

Autonomic responses to lateralized cold pressor and facial cooling tasks

“…In contrast, the present results are consistent with those of Burtis et al. (), who did not observe PNS lateralization in the visual system. PNS activity may present a less straightforward picture in terms of CNS lateralization.…”

“…Two general models have arisen from this body of research: one posits PNS activity as largely dependent on left hemisphere regulation (Craig, ), while the other has situated the PNS alongside the SNS in right hemisphere regulation (Thayer & Lane, ). Moreover, a recent study using ANS measures derived from the visual system found evidence for right‐lateralized sympathetic activity, but failed to detect parasympathetic lateralization (Burtis et al., ). Considering how vagal activity has increasingly been demonstrated as an important marker for physical (Gutin, Owens, Slavens, Riggs, & Treiber, ), emotional (Stein et al., ), cognitive (Brosschot, Gerin, & Thayer, ), and cardiovascular health (Thayer, Yamamoto, & Brosschot, ), a clearer understanding of PNS regulation is called for.…”

Origins of Pupillary Hippus in the Autonomic Nervous System

“…Individual lateralization asymmetries in the cortical innervation of the PNS and SNS may inadvertently bias monocular tasks, [23][24][25] so despite our treatment eye being randomly determined, the effect of eye was also investigated. However, the allocation of treatment eye did not affect the amount of dilation, relative to the paired control eye (t (16) ¼ À0.048, P ¼ 0.962), nor the change in hippus energy (t (16) ¼ 0.165, P ¼ 0.871).…”

“…18,19 Some have suggested that hippus is a function of SNS tone alone, 20 while others have suggested it is driven by the PNS input, 17,21 despite dissonance between accommodative microfluctuations and hippus. 22 Burtis et al 23 attempted to tease out the role of the PNS and SNS in hippus by exploiting both the modest asymmetry in monocular visual field projection and inherent cortical lateralization of the autonomic nervous system. [24][25][26] By occluding either the left or right eye to differentially activate each cortical hemisphere, and by extension the PNS or SNS, they saw slight differences in pupil dilation based on which eye was occluded, but their study lacked sufficient power to detect a difference in hippus activity.…”

Benign Anisocoria is related to Gender

“…Consistent with this thesis, asymmetry has been observed in several functional domains of the SNS, and most results suggest that the right side of the brain is more sympathetically active than the left. For example, stimulating the right-hemisphere with left-eye monocular viewing produces larger pupil dilation than when the left-hemisphere is stimulated [8,9]. Right-hemisphere lateralization has also been found in sympathetic cardiovascular control [10][11][12][13][14][15].…”