Data di Pubblicazione:
2008
Abstract:
To investigate the contribution of the vestibular velocity-storage mechanism (VSM) to the
vertical rotational vestibulo-ocular reflex (rVOR) we recorded eye movements evoked by off-vertical axis
rotation (OVAR) using whole-body constant-velocity pitch rotations about an earth-horizontal, interaural
axis in four healthy human subjects. Subjects were tumbled forward, and backward, at 60 deg/s for over
1 min using a 3D turntable. Slow-phase velocity (SPV) responses were similar to the horizontal responses
elicited by OVAR along the body longitudinal axis, (‘barbecue’ rotation), with exponentially decaying
amplitudes and a residual, otolith-driven sinusoidal response with a bias. The time constants of the vertical
SPV ranged from 6 to 9 s. These values are closer to those that reflect the dynamic properties of vestibular
afferents than the typical 20 s produced by the VSM in the horizontal plane, confirming the relatively
smaller contribution of the VSM to these vertical responses. Our preliminary results also agree with the
idea that the VSM velocity response aligns with the direction of gravity. The horizontal and torsional eye
velocity traces were also sinusoidally modulated by the change in gravity, but showed no exponential decay.
vertical rotational vestibulo-ocular reflex (rVOR) we recorded eye movements evoked by off-vertical axis
rotation (OVAR) using whole-body constant-velocity pitch rotations about an earth-horizontal, interaural
axis in four healthy human subjects. Subjects were tumbled forward, and backward, at 60 deg/s for over
1 min using a 3D turntable. Slow-phase velocity (SPV) responses were similar to the horizontal responses
elicited by OVAR along the body longitudinal axis, (‘barbecue’ rotation), with exponentially decaying
amplitudes and a residual, otolith-driven sinusoidal response with a bias. The time constants of the vertical
SPV ranged from 6 to 9 s. These values are closer to those that reflect the dynamic properties of vestibular
afferents than the typical 20 s produced by the VSM in the horizontal plane, confirming the relatively
smaller contribution of the VSM to these vertical responses. Our preliminary results also agree with the
idea that the VSM velocity response aligns with the direction of gravity. The horizontal and torsional eye
velocity traces were also sinusoidally modulated by the change in gravity, but showed no exponential decay.
Tipologia CRIS:
2.1 Contributo in volume (Capitolo o Saggio)
Keywords:
mathematical modeling; vestibular system; velocity storage mechanism
Elenco autori:
Bertolini, Giovanni; Bockisch, Cj; Straumann, D; Zee, Ds; Ramat, Stefano
Link alla scheda completa:
Titolo del libro:
Using eye movements as an experimental probe of brain function. A symposium in honor of Jean Büttner-Ennever
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