Gaze direction modulates finger movement activation patterns in human motor cortex

Baker JT, Donoghue JD, Sanes JN.  (1999)  Journal of Neuroscience, 19 (22): 10044-52.  

We investigated whether gaze direction modified the pattern of finger movement activation in human cerebral cortex using functional magnetic resonance imaging (MRI). Participants performed a sequential finger-tapping task or made no finger movements while maintaining gaze in the direction of the moving hand (aligned conditions) or away from the location of the moving hand. Functional MR signals, measured in the hemisphere contralateral to the moving hand, revealed finger movement-related activation in primary motor cortex, lateral and medial premotor cortex, and a wide extent of the lateral superior and inferior parietal lobules. In each area, the extent of the finger movement activation increased when static gaze was more aligned with the moving hand compared to when gaze was directed away from the moving hand. These data suggest the existence of large-scale cortical networks related to finger actions and indicate that skeletomotor processing in the cerebral cortex is consistently modified by gaze direction signals.

A, B, Color-coded illustration of the cortical regions assessed for functional MR activation. MI in red, PMA in green, SMA in purple, SPL in orange, and IPL in yellow.  VAC, Vertical plane through the anterior commissure perpendicular to a line between the anterior and posterior commissures; VPC, vertical plane through the posterior commissure perpendicular to a line between the anterior and posterior commissures. C, Functional MR labeling in two exemplar slices obtained from a single participant (slice planes indicated on whole brain volumes at right). The least activation occurred for leftward gaze, whereas that for both central and rightward gaze exceeded that for leftward gaze. The images with overlain label depict mostly portions of the left, contralateral hemisphere (L, left; R, right). Red arrowhead indicates fundus of central sulcus (indicated by green lines).