March 2012
Volume 53, Issue 14
Free
ARVO Annual Meeting Abstract  |   March 2012
Electromyographic Evidence of a Fast Response Functional Pathway between Retinal Ganglion Cells and Trigeminal Sensory Nucleus
Author Affiliations & Notes
  • Pieter Poolman
    Center for Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa
    Department of Ophthalmology and Visual Sciences,
    University of Iowa, Iowa City, Iowa
  • Lauren S. Talman
    University of Iowa, Iowa City, Iowa
  • Susan C. Anderson
    Center for Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa
    Department of Ophthalmology and Visual Sciences,
    University of Iowa, Iowa City, Iowa
  • Andrew F. Russo
    Molecular Physiology and Biophysics,
    University of Iowa, Iowa City, Iowa
  • Ana Recober
    Neurology,
    University of Iowa, Iowa City, Iowa
  • Jan M. Full
    Center for Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa
    Department of Ophthalmology and Visual Sciences,
    University of Iowa, Iowa City, Iowa
  • Randy H. Kardon
    Center for Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa
    Department of Ophthalmology and Visual Sciences,
    University of Iowa, Iowa City, Iowa
  • Footnotes
    Commercial Relationships  Pieter Poolman, None; Lauren S. Talman, None; Susan C. Anderson, None; Andrew F. Russo, None; Ana Recober, None; Jan M. Full, None; Randy H. Kardon, None
  • Footnotes
    Support  VA Rehabilitation Research and Development Division; VA Center for the Prevention and Treatment of Visual Loss, Iowa City, IA
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 4840. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Pieter Poolman, Lauren S. Talman, Susan C. Anderson, Andrew F. Russo, Ana Recober, Jan M. Full, Randy H. Kardon; Electromyographic Evidence of a Fast Response Functional Pathway between Retinal Ganglion Cells and Trigeminal Sensory Nucleus. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4840.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: : The Photo-Blink Reflex protects the eye after a bright flash of light (Mukuno et al 1983, Malin 1982, Yasahura et al 1982, Ozaki 1976). Melanopsin containing retinal ganglion cells (RGCs) may comprise the afferent arm of this reflex through projections to thalamus and the trigeminal nucleus (Noseda et al 2010). Okamoto et al (2010) have recently proposed that a slow trigeminal response could be mediated by changes in vessel size in the choroid in response to bright light and might help to explain how bright light causes pain. This study compared smooth muscle (iris-pupil light reflex) and skeletal muscle (electromyogram-EMG) responses to light stimuli varying in temporal frequency to determine if the photic-EMG can occur at a rate that is greater than what could be accounted for by vascular smooth muscle changes.

Methods: : Five subjects were tested under photopic conditions using red (640nm) and blue (485nm) Ganzfeld, full field light at 1, 10 and 275cd/m2. Each stimulus consisted of a sequence of fifteen light bursts, 50ms in duration, separated by dark intervals to obtain 1, 3, 5 and 10Hz trains. The time between each train of light was 60s. Conditions of color, intensity, and temporal frequency were presented in random order. Time-stamped, computerized recording of the pupil, and orbicularis and procerus EMG were collected simultaneously.

Results: : The smooth muscles of the pupil could track the 1Hz stimulus, with significant suppression at 3Hz, and with extinction of the effect at 5 and 10Hz. However, EMG amplitudes at 5 and 10Hz were on average still between 30-40% of their respective amplitudes for the 3Hz stimulus, even though the muscles were less likely to completely relax during the higher frequency sequences.

Conclusions: : This study provides the first physiological evidence in humans for a fast 10Hz light-induced EMG response. The photic-EMG appears to be mediated by RGCs which provide input to the trigeminal sensory nucleus, which then stimulates the facial nucleus, giving rise to the orbicularis and procerus EMG responses. Trigeminal input from vascular dilation/contraction cycles of smooth muscle in the choroidal vessels cannot explain the fast 5 and 10Hz response exhibited by facial muscles, and supports the notion of a separate, faster functional pathway between RGCs and the trigeminal sensory nucleus that could not be explained by changes in vascular tone leading to trigeminal activation.

Keywords: electrophysiology: non-clinical • pupillary reflex 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×