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Transformation of vestibular signals into motor commands in the vestibuloocular reflex pathways of monkeys.

Publication ,  Journal Article
Ramachandran, R; Lisberger, SG
Published in: J Neurophysiol
September 2006

Parallel pathways mediate the rotatory vestibuloocular reflex (VOR). If the VOR undergoes adaptive modification with spectacles that change the magnification of the visual scene, signals in one neural pathway are modified, whereas those in another are not. By recording the responses of vestibular afferents and abducens neurons for vestibular oscillations at frequencies from 0.5 to 50 Hz, we have elucidated how vestibular signals are processed in the modified versus unmodified VOR pathways. For the small stimuli we used (+/- 15 degrees/s), the afferents with the most regular spontaneous discharge fired throughout the cycle of oscillation even at 50 Hz, whereas afferents with more irregular discharge showed phase locking. For all afferents, the firing rate was in phase with stimulus head velocity at low frequencies and showed progressive phase lead as frequency increased. Sensitivity to head velocity increased steadily as a function of frequency. Abducens neurons showed highly regular spontaneous discharge and very little evidence of phase locking. Their sensitivity to head velocity during the VOR was relatively flat across frequencies; firing rate lagged head velocity at low frequencies and shifted to large phase leads as stimulus frequency increased. When afferent responses were provided as inputs to a two-pathway model of the VOR, the output of the model reproduced the responses of abducens neurons if the unmodified and modified VOR pathways had frequency-dependent internal gains and included fixed time delays of 1.5 and 9 ms. The phase shifts predicted by the model provide fingerprints for identifying brain stem neurons that participate in the modified versus unmodified VOR pathways.

Duke Scholars

Published In

J Neurophysiol

DOI

ISSN

0022-3077

Publication Date

September 2006

Volume

96

Issue

3

Start / End Page

1061 / 1074

Location

United States

Related Subject Headings

  • Visual Perception
  • Vestibule, Labyrinth
  • Reflex, Vestibulo-Ocular
  • Neurons
  • Neurology & Neurosurgery
  • Motor Activity
  • Male
  • Macaca mulatta
  • Eye Movements
  • Animals
 

Citation

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Ramachandran, R., & Lisberger, S. G. (2006). Transformation of vestibular signals into motor commands in the vestibuloocular reflex pathways of monkeys. J Neurophysiol, 96(3), 1061–1074. https://doi.org/10.1152/jn.00281.2006
Ramachandran, Ramnarayan, and Stephen G. Lisberger. “Transformation of vestibular signals into motor commands in the vestibuloocular reflex pathways of monkeys.J Neurophysiol 96, no. 3 (September 2006): 1061–74. https://doi.org/10.1152/jn.00281.2006.
Ramachandran R, Lisberger SG. Transformation of vestibular signals into motor commands in the vestibuloocular reflex pathways of monkeys. J Neurophysiol. 2006 Sep;96(3):1061–74.
Ramachandran, Ramnarayan, and Stephen G. Lisberger. “Transformation of vestibular signals into motor commands in the vestibuloocular reflex pathways of monkeys.J Neurophysiol, vol. 96, no. 3, Sept. 2006, pp. 1061–74. Pubmed, doi:10.1152/jn.00281.2006.
Ramachandran R, Lisberger SG. Transformation of vestibular signals into motor commands in the vestibuloocular reflex pathways of monkeys. J Neurophysiol. 2006 Sep;96(3):1061–1074.

Published In

J Neurophysiol

DOI

ISSN

0022-3077

Publication Date

September 2006

Volume

96

Issue

3

Start / End Page

1061 / 1074

Location

United States

Related Subject Headings

  • Visual Perception
  • Vestibule, Labyrinth
  • Reflex, Vestibulo-Ocular
  • Neurons
  • Neurology & Neurosurgery
  • Motor Activity
  • Male
  • Macaca mulatta
  • Eye Movements
  • Animals