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Article
Postural responses to unexpected perturbations of balance during reaching
Faculty of Health and Behavioural Sciences - Papers (Archive)
  • Hari Trivedi, Emory University
  • Julia A Leonard, McGill University
  • Lena H Ting, Emory University
  • Paul J Stapley, McGill University
RIS ID
37986
Publication Date
1-1-2010
Publication Details

Trivedi, H., Leonard, J. A., Ting, L. H. & Stapley, P. J. (2010). Postural responses to unexpected perturbations of balance during reaching. Experimental Brain Research, 202 (2), 485-491.

Abstract

To study the interaction between feedforward and feedback modes of postural control, we investigated postural responses during unexpected perturbations of the support surface that occurred during forward reaching in a standing position. We examined postural responses in lower limb muscles of nine human subjects. Baseline measures were obtained when subjects executed reaching movements to a target placed in front of them (R condition) and during postural responses to forward and backward support-surface perturbations (no reaching, P condition) during quiet stance. Perturbations were also given at different delays after the onset of reaching movements (RP conditions) as well as with the arm extended in the direction of the target, but not reaching (P/AE condition). Results showed that during perturbations to reaching (RP), the initial automatic postural response, occurring around 100 ms after the onset of perturbations, was relatively unchanged in latency or amplitude compared to control conditions (P and P/AE). However, longer latency postural responses were modulated to aid in the reaching movements during forward perturbations but not during backward perturbations. Our results suggest that the nervous system prioritizes the maintenance of a stable postural base during reaching, and that later components of the postural responses can be modulated to ensure the performance of the voluntary task. Keywords Human Posture Feedforward Feedback Reaching

Citation Information
Hari Trivedi, Julia A Leonard, Lena H Ting and Paul J Stapley. "Postural responses to unexpected perturbations of balance during reaching" (2010) p. 485 - 491
Available at: http://works.bepress.com/pstapley/16/