Effects of vestibular and oculomotor stimulation on responsiveness of the carotid-cardiac baroreflex

Victor A. Convertino, Fred H. Previc, David A. Ludwig, Edward J. Engelken

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Twelve healthy men underwent measurement of their carotid-cardiac baroreflex response during varying conditions of vestibulo-oculomotor stimulation to test the hypothesis that vestibular and/or oculomotor stimulation associated with head movements in the yaw plane inhibit baroreflex control of heart rate. We assessed the carotid-cardiac baroreflex response by plotting R-R intervals (in milliseconds) at each of eight neck pressure steps with their respective carotid distending pressures (in millimeters mercury). Baroreflex sensitivity was measured under four experimental conditions: 1) sinusoidal whole body yaw rotation of the subject in the dark without visual fixation (combined vestibular-oculomotor stimulation); 2) yaw oscillation of the subject while tracking a small head- fixed light moving with the subject (vestibular stimulation without eye movements); 3) subject stationary while fixating on a small light oscillating in yaw at the same frequency, peak acceleration, and velocity as the chair (eye movements without vestibular stimulation); and 4) subject stationary in the dark (no eye or head motion). Head motion alone reduced baseline baroreflex responsiveness by 30% from 3.8 ± 0.5 to 2.6 ± 0.5 ms/mmHg. Eye motion alone also reduced the baroreflex response by 13% (0.5 ms/mmHg) to 3.3 ± 0.5 ms/mmHg. During head motion, the effect of eye motion was negligible (2.7 ± 0.4 ms/mmHg). These results suggest that vestibular stimulation associated with head movements in yaw inhibits vagally mediated baroreflex control of heart rate, whereas oculomotor stimulation is less of a factor and only in the absence of vestibular stimulation.

Original languageEnglish (US)
Pages (from-to)R615-R622
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume273
Issue number2 42-2
StatePublished - Oct 18 1997

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Keywords

  • Autonomic function
  • Heart rate
  • Oculomotion
  • Vestibular function

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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