Enhancement of the bias component of downbeat nystagmus after lesions of the nodulus and uvula.
In two monkeys, we recorded spontaneous eye movements before and after ablation of the cerebellar nodulus and uvula (Nod/Uv). In both monkeys, there was an increase in upward ocular drift (downbeat nystagmus [DBN]) in darkness (M1: 1.5 degrees/s pre, 3.4 degrees/s post; M2: 1.3 degrees/s pre, 7.0 degrees/s post), but not in light. There was little effect of orbital position on drift velocity. These findings suggest that the Nod/Uv may play a role in the bias component of DBN.
Walker
Mark F
MF
Department of Neurology, Case Western Reserve University, Cleveland VA Medical Center, Cleveland, Ohio, USA. mark.walker@case.edu
Tian
Jing
J
Shan
Xiaoyan
X
Ying
Howard
H
Tamargo
Rafael J
RJ
Zee
David S
DS
D000818:Animals; D008253:Macaca mulatta; D009759:Nystagmus, Pathologic / Q000503:physiopathology*; D014609:Uvula / Q000473:pathology*