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Role of the Dorsolateral Pontine Nucleus in Visual‐Vestibular Behavior
Author(s) -
MUSTARI MICHAEL J.,
ONO SEIJI,
DAS VALLABH E.,
TUSA RONALD J.
Publication year - 2003
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1303.017
Subject(s) - vestibulo–ocular reflex , vestibular system , neuroscience , vestibular nuclei , efference copy , psychology , smooth pursuit , reflex , muscimol , climbing fiber , stimulation , cerebellum , eye movement , medicine , cerebellar cortex , receptor , gabaa receptor
Visual‐vestibular behavior depends on signals traveling in climbing and mossy fiber pathways. Our study examined the role of the dorsolateral pontine nucleus (DLPN), a major component of the cortico‐ponto‐cerebellar mossy fiber pathway. DLPN neurons discharge in relation to smooth pursuit and during visual stimulation, indicating a potential role in visually guided motor learning in the vestibulo‐ocular reflex (VOR). We used unilateral muscimol injections to determine the potential role of the DLPN in short‐term VOR gain adaptation. Preinjection adaptation of VOR gain was achieved by sinusoidal rotation (0.2 Hz, 30°/s) for 2 h while the monkey viewed a stationary visual surround through either magnifying (×2) or minifying (×0.5) lenses. VOR gain increases (23‐32%) or decreases (22‐48%) as measured in complete darkness (VORd) were achieved. Following DLPN inactivation, initial acceleration of ipsilateral smooth‐pursuit was reduced by 35‐68%, and steady state gain was reduced by 32‐61%. Furthermore, the monkey's ability to cancel the VOR was impaired. In contrast to these significant deficits in ipsilesional smooth pursuit, the VOR during lens viewing was similar to that measured in preinjection control experiments. Similarly, following 2 h of adaptation, VORd gain adaptation was indistinguishable from control adaptation values for either ipsilesional or contralesional directions of head rotation. Our results suggest that visual error signals for short‐term adaptation of the VOR are derived from sources other than the DLPN, such as those from the accessory optic system.