Vestibular activation differentially modulates human early visual cortex and V5/MT excitability and response entropy

Barry M Seemungal, Jessica Guzman-Lopez, Qadeer Arshad, Simon R Schultz, Vincent Walsh, Nada Yousif

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Head movement imposes the additional burdens on the visual system of maintaining visual acuity and determining the origin of retinal image motion (i.e., self-motion vs. object-motion). Although maintaining visual acuity during self-motion is effected by minimizing retinal slip via the brainstem vestibular-ocular reflex, higher order visuovestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher order mechanisms, and a cortical visuovestibular reciprocal antagonism is propounded. Hence, one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased early visual cortex (EVC) excitability, during vestibular activation. In order to exclude nonspecific effects (e.g., arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a nonspecific effect at EVC.

Original languageEnglish
Pages (from-to)12-19
Number of pages8
JournalCerebral cortex (New York, N.Y. : 1991)
Issue number1
Publication statusPublished - 1 Jan 2013


  • Adult
  • Algorithms
  • Arousal
  • Caloric Tests
  • Entropy
  • Female
  • Humans
  • Male
  • Nerve Net
  • Neuronal Plasticity
  • Photic Stimulation
  • Reflex, Vestibulo-Ocular
  • Transcranial Magnetic Stimulation
  • Vestibule, Labyrinth
  • Visual Cortex


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