In vivo definition of parieto-motor connections involved in planning of grasping movements

Neuroimage. 2010 May 15;51(1):300-12. doi: 10.1016/j.neuroimage.2010.02.022. Epub 2010 Feb 13.


We combined bifocal transcranial magnetic stimulation (TMS) and diffusion tensor imaging (DTI) tractography to investigate in humans the contribution of connections originating from different parietal areas in planning of different reaching to grasp movements. TMS experiments revealed that in the left hemisphere functional connectivity between the primary motor cortex (M1) and a portion of the angular gyrus (AG) close to the caudal intraparietal sulcus was activated during early preparation of reaching and grasping movements only when the movement was made with a whole hand grasp (WHG) towards objects in contralateral space. In contrast, a different pathway, linking M1 with a part of the supramarginal gyrus (SMG) close to the anterior intraparietal sulcus, was sensitive only to the type of grasp required (precision grasping) but not to the position of the object in space. A triple coil experiment revealed that inactivation of the ventral premotor area (PMv) by continuous theta burst stimulation interfered with some of these interactions. Anatomical DTI tractography revealed that AG and SMG are strongly connected with PMv and with M1 by different bundles of the superior longitudinal fasciculus (SLF). These results demonstrate the existence of segregated parieto-premotor-motor pathways crucial for preparation of different grasping actions and indicate that these may process information relevant to both the position of the object and the hand shape required to use it.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diffusion Tensor Imaging
  • Evoked Potentials, Motor
  • Female
  • Frontal Lobe / anatomy & histology
  • Frontal Lobe / physiology*
  • Functional Laterality
  • Hand / physiology*
  • Humans
  • Male
  • Motor Activity / physiology*
  • Motor Cortex / anatomy & histology
  • Motor Cortex / physiology*
  • Motor Skills / physiology
  • Neural Pathways / anatomy & histology
  • Neural Pathways / physiology
  • Parietal Lobe / anatomy & histology
  • Parietal Lobe / physiology*
  • Psychomotor Performance / physiology*
  • Transcranial Magnetic Stimulation
  • Young Adult