H.G. and K.T. contributed equally to the study.
Reduced saccadic resilience and impaired saccadic adaptation due to cerebellar disease
Article first published online: 21 DEC 2007
European Journal of Neuroscience
Volume 27, Issue 1, pages 132–144, January 2008
How to Cite
Golla, H., Tziridis, K., Haarmeier, T., Catz, N., Barash, S. and Thier, P. (2008), Reduced saccadic resilience and impaired saccadic adaptation due to cerebellar disease. European Journal of Neuroscience, 27: 132–144. doi: 10.1111/j.1460-9568.2007.05996.x
- Issue published online: 21 DEC 2007
- Article first published online: 21 DEC 2007
- Received 10 July 2007, revised 12 November 2007, accepted 15 November 2007
- motor learning;
- saccade kinematics;
The term short-term saccadic adaptation (STSA) captures our ability to unconsciously move the endpoint of a saccade to the final position of a visual target that has jumped to a new location during the saccade. STSA depends on the integrity of the cerebellar vermis. We tested the hypothesis that STSA reflects the working of a cerebellar mechanism needed to avoid ‘fatigue’, a gradual drop in saccade amplitude during a long series of stereotypic saccades. To this end we compared the kinematics of saccades of 14 patients suffering from different forms of cerebellar disease with those of controls in two tests of STSA and a test of saccadic resilience. Controls showed an increase in saccade amplitude (SA) for outward adaptation, prompted by outward target shifts, due to an increase in saccade duration (SD) in the face of constant peak velocity (PV). The decrease in SA due to inward adaptation was, contrariwise, accompanied by a drop in PV and SD. Whereas patients with intact vermis did not differ from controls, those with vermal pathology lacked outward adaptation: SD remained constant, as did SA and PV. In contrast, vermal patients demonstrated a significant decrease in SA, paralleled by a decrease in PV but mostly unaltered SD in the inward adaptation experiment as well as in the resilience test. These findings support the notion that inward adaptation is at least partially based on uncompensated fatigue. On the other hand, outward adaptation reflects an active mechanism for the compensation of fatigue, residing in the cerebellum.