کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9429632 | 1297053 | 2005 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A unified view of quiet and perturbed stance: simultaneous co-existing excitable modes
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
علوم اعصاب (عمومی)
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چکیده انگلیسی
When standing quietly, human upright stance is typically approximated as a single segment inverted pendulum. In contrast, investigations which perturb upright stance with support surface translations or visual driving stimuli have shown that the body behaves like a two-segment pendulum, displaying both in-phase and anti-phase patterns between the upper and lower body. Here we present evidence that a single-segment characterization of quiet stance is inadequate. Similar to perturbed stance, quiet stance has simultaneously co-existing in-phase and anti-phase patterns. Subjects stood with eyes closed in three sensory conditions: a fixed surface, a foam surface, and a sway-referenced surface. Spectral analysis showed that the body behaved like a multi-link pendulum with two co-existing modes. The angles of the trunk and leg segments were in-phase for frequencies below 1Â Hz and anti-phase for frequencies above 1Â Hz. The shift from in-phase to anti-phase sway showed an abrupt change for the fixed and foam surfaces, but a gradual change for the sway-referenced condition with the trunk showing a phase lead over the legs. The coexistence of in-phase and anti-phase patterns during quiet stance suggests that the ankle and hip strategies are not extremes along a behavioral continuum of mixed strategies. They are “simultaneously co-existing excitable modes”, both always present, but one of which may predominate depending upon the characteristics of the available sensory information, task or perturbation.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuroscience Letters - Volume 377, Issue 2, 29 March 2005, Pages 75-80
Journal: Neuroscience Letters - Volume 377, Issue 2, 29 March 2005, Pages 75-80
نویسندگان
Robert Creath, Tim Kiemel, Fay Horak, Robert Peterka, John Jeka,