AI Article Synopsis
- The study examined how functional ablation and irregular otolith afferents affect the translational vestibuloocular reflexes (trVORs) in rhesus monkeys.
- The research involved applying short-duration electrical currents to the monkeys while they were exposed to various types of motion stimuli, revealing that anodal (inhibitory) currents significantly reduced trVOR sensitivity and increased eye response lags.
- The findings suggest that both regular and irregular afferents play a role in trVOR dynamics, with anodal stimulation decreasing eye velocity during prolonged rotations, highlighting the complexities of vestibular system responses.
Article Abstract
The effects of functional, reversible ablation and potential recruitment of the most irregular otolith afferents on the dynamics and sensitivity of the translational vestibuloocular reflexes (trVORs) were investigated in rhesus monkeys trained to fixate near and far targets. Translational motion stimuli consisted of either steady-state lateral and fore-aft sinusoidal oscillations or short-lasting transient lateral head displacements. Short-duration (usually <2 s) anodal (inhibitory) and cathodal (excitatory) currents (50-100 microA) were delivered bilaterally during motion. In the presence of anodal labyrinthine stimulation, trVOR sensitivity and its dependence on viewing distance were significantly decreased. In addition, anodal currents significantly increased phase lags. During transient motion, anodal stimulation resulted in significantly lower initial eye acceleration and more sluggish responses. Cathodal currents tended to have opposite effects. The main characteristics of these results were simulated by a simple model where both regularly and irregularly discharging afferents contribute to the trVORs. Anodal labyrinthine currents also were found to decrease eye velocity during long-duration, constant velocity rotations, although results were generally more variable compared with those during translational motion.
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| http://dx.doi.org/10.1152/jn.2000.83.3.1662 | DOI Listing |
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