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Is the velocity-curvature relationship disrupted in apraxic patients?
S Jacobs1, S Hanneton, S Heude
1CNRS UMR 8119. 45, rue des Saints Pères, 75006 Paris, France. stephane.jacobs@biomdicale.univ-paris5.fr
Abstract:
Velocity and curvature of human movements are linked by a proportionality relationship (power-law) whose origin has been attributed either to functional properties of cortical areas or to peripheral constraints. 3D movements made by apraxic patients show a time-shift between velocity and curvature which has been considered as a disruption of the power-law, supporting the central hypothesis. We analysed the power-law in 2D drawing-like movements in healthy subjects and apraxic patients (correlation and cross-correlation analyses). The power-law remained preserved in apraxic patients, suggesting that the velocity-curvature relationship is not globally disrupted and thus that the power-law cannot be only attributed to central planning mechanisms in those associative brain areas injured in apraxic patients.
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