Cortical Activations in Humans Grasp-Related Areas Depend on Hand Used and Handedness

Department of General Psychology, University of Padua, Padua, Italy.
PLoS ONE (Impact Factor: 3.23). 02/2008; 3(10):e3388. DOI: 10.1371/journal.pone.0003388
Source: PubMed


In non-human primates grasp-related sensorimotor transformations are accomplished in a circuit involving the anterior intraparietal sulcus (area AIP) and both the ventral and the dorsal sectors of the premotor cortex (vPMC and dPMC, respectively). Although a human homologue of such a circuit has been identified whether activity within this circuit varies depending on handedness has yet to be investigated.
We used functional magnetic resonance imaging (fMRI) to explicitly test how handedness modulates activity within human grasping-related brain areas. Right- and left-handers subjects were requested to reach towards and grasp an object with either the right or the left hand using a precision grip while scanned. A kinematic study was conducted with similar procedures as a behavioral counterpart for the fMRI experiment. Results from a factorial design revealed significant activity within the right dPMC, the right cerebellum and AIP bilaterally. The pattern of activity within these areas mirrored the results found for the behavioral study.
Data are discussed in terms of an handedness-independent role for the right dPMC in monitoring hand shaping, the need for bilateral AIP activity for the performance of precision grip movements which varies depending on handedness and the involvement of the cerebellum in terms of its connections with AIP. These results provide the first compelling evidence of specific grasping related neural activity depending on handedness.

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    • "In humans, both functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) studies have demonstrated the existence of localized cortical reach-to-grasp areas similar to those described in monkeys (Cavina-Pratesi et al. 2007; Culham et al. 2006; Kroliczak et al. 2007; Tunik et al. 2007; for reviews see Castiello 2005; Castiello and Begliomini 2008; Filimon 2010). Overall, reach-to-grasp fMRI studies converge in considering the anterior part of the human intraparietal sulcus (hAIP), a likely homolog of monkey AIP (Grafton et al. 1996; Culham et al. 2003; Frey et al. 2005; Begliomini et al. 2007a; Hinkley et al. 2009). "
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