Ocular stability and set-point adaptation

D. S. Zee, P. Jareonsettasin, R. J. Leigh

Research output: Contribution to journalReview article

Abstract

A fundamental challenge to the brain is how to prevent intrusive movements when quiet is needed. Unwanted limb movements such as tremor impair fine motor control and unwanted eye drifts such as nystagmus impair vision. Astable platformis also necessary to launch accurate movements. Accordingly, nature has designed control systems with agonist (excitation) and antagonist (inhibition) muscle pairs functioning in push–pull, around a steady level of balanced tonic activity, the set-point. Sensory information can be organized similarly, as in the vestibulo-ocular reflex, which generates eye movements that compensate for head movements. The semicircular canals, working in coplanar pairs, one in each labyrinth, are reciprocally excited and inhibited as they transduce head rotations. The relative change in activity is relayed to the vestibular nuclei, which operate around a set-point of stable balanced activity. When a pathological imbalance occurs, producing unwanted nystagmus without head movement, an adaptive mechanism restores the proper set-point and eliminates the nystagmus. Here we used 90 min of continuous 7 T magnetic field labyrinthine stimulation (MVS) in normal humans to produce sustained nystagmus simulating vestibular imbalance. We identified multiple timescale processes towards a new zero set-point showing that MVS is an excellent paradigm to investigate the neurobiology of set-point adaptation.

Original languageEnglish (US)
Article number20160199
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Volume372
Issue number1718
DOIs
StatePublished - Apr 19 2017

Keywords

  • Adaptation
  • Homeostasis
  • Magnetic field
  • Set-point
  • Vestibular

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

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