Overlapping neural circuits for visuospatial attention and eye movements in human cerebellum.

Abstract

Previous research in patients with cerebellar damage suggests that the cerebellum may play a role in visual attention. One limitation of some of these studies is that they examined patients with heterogeneous cerebellar damage. As a result, the patterns of reported deficits have been inconsistent. In the current study we used functional neuroimaging (fMRI) in healthy adults (n=14) to examine whether the cerebellum plays an important role in visual attention. During the fMRI session, subjects performed two covert attention tasks in which they were cued (with peripheral flashes or central directional arrows) to attend to marked locations in the visual periphery without moving their eyes. Using a block design, we compared BOLD activation in these covert attention conditions to a number of control conditions including: the same attention tasks with eye movements, a target detection task with no cuing, and a self paced button-press task in order to rule out the possibility that any activation observed in the cerebellum during the covert attention tasks might be due to motor output associated with task performance. Results indicated that, in addition to the usual fronto-parietal networks commonly engaged by this visual attention task, two regions of the cerebellum (lobule 6 in the left posterior quadrangular lobe and the culmen) were active when subjects performed the attention task with peripheral cues with or without concomitant eye movements. The same regions of the cerebellum were not active, however, when subjects performed the covert attention task using central arrow cues. This suggests that the cerebellum may play a critical role in both shifting attention and generating eye movements towards stimuli that suddenly appear in the periphery. These results are consistent with the pre-motor theory of attention which posits that shifts of attention are generated through the programming of eye movements that are not executed. Meeting abstract presented at VSS 2012