RT Journal Article
SR Electronic
T1 Dissociating the Role of Ventral and Dorsal Premotor Cortex in Precision Grasping
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2260
OP 2268
DO 10.1523/JNEUROSCI.3386-05.2006
VO 26
IS 8
A1 Marco Davare
A1 Michael Andres
A1 Guy Cosnard
A1 Jean-Louis Thonnard
A1 Etienne Olivier
YR 2006
UL http://www.jneurosci.org/content/26/8/2260.abstract
AB Small-object manipulation is essential in numerous human activities, although its neural bases are still essentially unknown. Recent functional imaging studies have shown that precision grasping activates a large bilateral frontoparietal network, including ventral (PMv) and dorsal (PMd) premotor areas. To dissociate the role of PMv and PMd in the control of hand and finger movements, we produced, by means of transcranial magnetic stimulation (TMS), transient virtual lesions of these two areas in both hemispheres, in healthy subjects performing a grip–lift task with their right, dominant hand. We found that a virtual lesion of PMv specifically impaired the grasping component of these movements: a lesion of either the left or right PMv altered the correct positioning of fingers on the object, a prerequisite for an efficient grasping, whereas lesioning the left, contralateral PMv disturbed the sequential recruitment of intrinsic hand muscles, all other movement parameters being unaffected by PMv lesions. Conversely, we found that a virtual lesion of the left PMd impaired the proper coupling between the grasping and lifting phases, as evidenced by the TMS-induced delay in the recruitment of proximal muscles responsible for the lifting phase; lesioning the right PMd failed to affect dominant hand movements. Finally, an analysis of the time course of these effects allowed us to demonstrate the sequential involvement of PMv and PMd in movement preparation. These results provide the first compelling evidence for a neuronal dissociation between the different phases of precision grasping in human premotor cortex.