[Abstract Title]. - Society for Neuroscience

Program#/Poster#: 264.10/DD27
Topic: D.06.d. Saccades and Pursuit
Title: Neural activities related to smooth pursuit and saccade eye movements in the primate
cerebellar hemispheric lobules VI/VII
Authors: *H. KITAZAWA 1 , M. OHKI 2 , T. KITAMURA 3 , J. YAMADA 3 , S. NAGAO 1,4 ;
1 Lab. Motor Learning Control, RIKEN BSI, Wako, Japan; 2 Otolaryngol., Grad. Sch. of Med.,
Univ. of Tokyo, Tokyo, Japan; 3 Histo&Neuroanat, Tokyo Med. Univ., Tokyo, Japan; 4 SORST,
Saitama, Japan
Abstract: Primate cerebellar hemispheric lobules VI/VII (H-VI/VII), as well as the vermal
lobules VI/VII, receive inputs issued from the frontal eye field. We previously reported that
lesions of H-VI/VII appreciably depressed velocities of smooth pursuit eye movements and
delayed the onsets of saccades. In the present study, we recorded single-unit activities of H-
VI/VII Purkinje cells from two macaque monkeys to examine their responses to smooth pursuit
and visually-guided saccade eye movements. We classified simple spike responses of H-VI/VII
Purkinje cells into the following 4 groups. Group 1(51/138) increased simple spike discharges
transiently at both the saccade and pursuit onsets. The increase in spike activities advanced the
onsets of saccade eye movements by 10-100ms, and those of smooth pursuit by 10-50ms.
Purkinje cells exhibited no directional preferences. Group 2 (46/138) and group 3 (17/138)
increased simple spike discharges only at the onsets of saccade and smooth pursuit, respectively.
One-third of the group 1 and 3 cells tested showed smooth pursuit velocity- or accelerationrelated
responses. Group 4 (5/138) decreased simple spike discharges transiently at the onsets of
saccade or smooth pursuit. Slow or quick eye movements, predominantly in the oblique
directions, were induced by microstimulation in 30 % of the areas where these Purkinje cells
were recorded. Taken together these results with those of previous lesion study, we suggest that
the H-VI/VII plays an important role in the velocity tuning of the early (open-loop) component
of smooth pursuit, and also in the initiation timing of saccade.
Disclosures: H. Kitazawa, None; M. Ohki, None; T. Kitamura, None; J. Yamada, None; S.
Nagao, None.
Poster
264. Eye Movements: Smooth Pursuit
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 264.11/DD28
Topic: D.06.b. Cortex and thalamus