| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 U.S. Army Institute of Surgical Research, Fort Sam Houston, TX, USA; Biological Sciences, Michigan Technological University, Houghton, MI, USA
2 Biological Sciences, Michigan Technological University, Houghton, MI, USA
3 Physics, University of Turku, Turku, Finland
* To whom correspondence should be addressed. E-mail: william.cooke{at}amedd.army.mil.
Otolith activation increases muscle sympathetic nerve activity (MSNA), and MSNA activation may alter associations among autonomic oscillators including those modulating cerebral hemodynamics. The purpose of this study was to determine the influence of vestibulosympathetic activation on cerebral and autonomic rhythms. We recorded the ECG, finger arterial pressure, end-tidal CO2, respiration, cerebral blood flow velocity, and MSNA in 8 subjects. Subjects breathed at 0.25 Hz for 5 min in the prone and head-down positions. We analyzed data in time- and frequency-domains and performed cross-spectral analyses to determine coherence and transfer function magnitude. Head-down rotation increased MSNA from 7 ± 1.3 to 12 ± 1.5 bursts/min (P = 0.001), but did not affect R-R intervals, arterial pressures, mean cerebral blood flow velocities (Vmean), or their power spectra. Vestibular activation with head-down rotation had no effect on mean arterial pressure and Vmean transfer function magnitude. The two new findings from this study are: 1) Head-down rotation independently activates the sympathetic nervous system with no effect on parasympathetic activity or Vmean; and 2) Frequency-dependent associations between arterial pressures and Vmean are independent of vestibular activation. These findings support the concept that vestibular-autonomic interactions independently and redundantly serve to maintain steady-state hemodynamics.
This article has been cited by other articles:
|
|
 |
|
  T. D. Wilson, L. A. Cotter, J. A. Draper, S. P. Misra, C. D. Rice, S. P. Cass, and B. J. Yates Effects of postural changes and removal of vestibular inputs on blood flow to the head of conscious felines J Appl Physiol, May 1, 2006; 100(5): 1475 - 1482. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Krishnamurthy, X. Wang, D. Bhakta, E. Bruce, J. Evans, T. Justice, and A. Patwardhan Dynamic cardiorespiratory interaction during head-up tilt-mediated presyncope Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2510 - H2517. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. W. Hamner, M. A. Cohen, S. Mukai, L. A. Lipsitz, and J. A. Taylor Spectral indices of human cerebral blood flow control: responses to augmented blood pressure oscillations J. Physiol., September 15, 2004; 559(3): 965 - 973. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
