Functional imaging of changes in cerebellar activity related to learning during a novel eye–hand tracking task
Coordination between the eyes and the hand is likely to be based on a process of motor learning, so that the interactions between the two systems can be accurately controlled. By using an unusual tracking task we measured the change in brain activation levels, as recorded with 3T functional magnetic resonance imaging (fMRI), between naïve human subjects and the same subjects after a period of extended training. Initially the performance of the two groups was similar. One subject group was then trained in a synchronous, coordinated, eye–hand task; the other group trained with a 304 ms temporal offset between hand and eye tracking movements. After training, different patterns of performance were observed for the groups, and different functional activation profiles. Significant change in the relationship between functional activation levels and eye–hand task conditions was predominantly restricted to visuo-motor areas of the lateral and vermal cerebellum. In an additional test with one of the subject groups, we show that there was increased cerebellar activation after learning, irrespective of change in performance error. These results suggest that two factors contribute to the measured blood oxygen level-dependent (BOLD) signal. One declined with training and may be directly related to performance error. The other increased after training, in the test conditions nearest to the training condition, and may therefore be related to acquisition of experience in the task. The loci of activity changes suggest that improved performance is because of selective modified processing of ocular and manual control signals within the cerebellum. These results support the suggestion that coordination between eye and hand movement is based on an internal model acquired by the cerebellum that provides predictive signals linking the control of the two effectors.
KeywordsHuman Coordination Functional imaging Cerebellum Motor learning
This work was funded by a Wellcome Trust Fellowship to RCM and by MRC support of the Oxford FMRIB Centre. We thank all FMRIB staff for their technical support, analysis software and advice, and thank Ji-Hang Lee for his data on eye tracking performance mentioned in the results.
- Duvernoy HM (1999) The human brain surface, blood supply, and three-dimensional sectional anatomy. Springer-Verlag Wein, New YorkGoogle Scholar
- Lewis RF, Zee DS (1993) Ocular motor disorders associated with cerebellar lesions: pathophysiology and topical localization. Rev Neurol (Paris) 149:665–677Google Scholar
- Smith SM (2001) Overview of fMRI analysis. In: Jezzard P, Matthews PM, Smith SM (eds) Functional MRI: an introduction to methods. Oxford University Press, Oxford, pp 215–227Google Scholar
- Talairach J, Tournoux P (1988) Co-planar stereotaxic atlas of the human brain. Georg Thieme Verlag, StuttgartGoogle Scholar