The role of V5 (hMT+) in visually guided hand movements: an fMRI
study
C. Oreja-Guevara, R. Kleiser, W. Paulus, W. Kruse, R.J. Seitz & K.-P. Hoffmann
European Journal of Neuroscience, 19:3113-3120, 2004
- Electrophysiological studies in animals suggest that visuomotor control of forelimb and eye movements involves
reciprocal connections between several areas (striate, extrastriate, parietal, motor and premotor) related to movement
performance and visuospatial coding of movement direction. The extrastriate area MT [V5 (hMT+) in humans] located
in the "dorsal pathway" of the primate brain is specialized in the processing of visual motion information.
The aim of our study was to investigate the functional role of V5 (hMT+) in the control of visually guided hand
movements and to identify the corresponding cortex activation implicated in the visuomotor tasks using functional
magnetic resonance imaging. Eight human subjects performed visually guided hand movements, either continuously
tracking a horizontally moving target or performing ballistic tracking movements of a cursor to an eccentric stationary
target while fixating a central fixation cross. The tracking movements were back-projected onto the screen using
a cursor which was moved by an MRI-compatible joystick. Both conditions activated area V5 (hMT+), right more than
left, particularly during continuous tracking. In addition, a large-scale sensorimotor circuit which included sensorimotor
cortex, premotor cortex, striatum, thalamus and cerebellum as well as a number of cortical areas along the intraparietal
sulcus in both hemispheres were activated. Because activity was increased in V5 (hMT+) during continuous tracking
but not during ballistic tracking as compared to motion perception, it has a pivotal role during the visual control
of forelimb movements as well.
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