A lesion of the posterior parietal cortex disrupts on-line adjustments during aiming movements.

1. Neuropsychologia. 2002;40(13):2471-80. doi: 10.1016/s0028-3932(02)00009-x.

A lesion of the posterior parietal cortex disrupts on-line adjustments during
aiming movements.

Gréa H(1), Pisella L, Rossetti Y, Desmurget M, Tilikete C, Grafton S, Prablanc
C, Vighetto A.

Author information:
(1)Espace et Action INSERM Unité 534, 16 Avenue du Doyen Lépine, CP 13, 69676
Cedex, Bron, France.

It is long known that the posterior parietal cortex (PPC) is critically involved
in goal-directed movements. Nevertheless, there are still some controversies
about its specific functions. Although most published studies have emphasised
the role of PPC in sensorimotor planning processes, it has been recently
suggested that PPC can also participate to on-line movement control. We studied
kinematics of hand movements in a patient with a bilateral PPC lesion who
exhibited no deficit in planning of her grasping movements in central vision.
She was instructed to reach and grasp a cylinder presented at different
locations and her motor performance was compared to that of four healthy control
subjects. To address on-line control specifically, the cylinder was quickly and
unexpectedly jumped, on a few trials, at movement onset, to a new location some
10 degrees (of apparent visual angle) from the original location. The patient
could easily grasp stationary objects seen in foveal vision, exhibiting the same
kinematic pattern as controls. Therefore, she could plan movements accurately.
In response to the object jump, unlike the controls, the patient was unable to
amend her ongoing movement. In this situation, she completed two distinct
movements, a first one toward the initial object location and a second one
toward the final object location. These results support the hypothesis that
beyond a role in movement planning, PPC plays a major role in the on-line
control of reach-to-grasp movements.

DOI: 10.1016/s0028-3932(02)00009-x
PMID: 12417474 [Indexed for MEDLINE]

Auteurs Bordeaux Neurocampus