On action intent : behavioural correlates of reach-to-grasp actions

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Flindall, Jason
University of Lethbridge. Faculty of Arts and Science
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Lethbridge, Alta : University of Lethbridge, Dept. of Neuroscience
Evidence from electrophysiology suggests that non-human primates produce reach-to-grasp movements based on their functional end-goal rather than on the biomechanical requirements of the movement. However, the invasiveness of direct-electrical stimulation and single-neuron recording studies have precluded analogous investigations in humans. In this thesis, I present behavioural evidence in the form of kinematic analyses suggesting that the cortical circuits responsible for reach-to-grasp actions in humans are organized in a similar fashion. Grasp-to-eat movements are produced with significantly smaller and more precise maximum grip apertures (MGAs) than are grasp-to-place movements directed toward the same objects, despite near identical mechanical requirements of the two subsequent (i.e., -eat and –place) movements. Furthermore, the fact that this distinction is limited to right-handed movements suggests that the system governing reach-to-grasp movements is asymmetric. I posit that this asymmetry may be responsible, at least in part, for the preponderance of right-hand dominance among the global population.
kinematics , neuroscience , behaviour , grasp-to-eat , reach-to-grasp , asymmetries