An investigation into the neural mechanisms of human balance control

Osborne, Timothy Mark (2013). An investigation into the neural mechanisms of human balance control. University of Birmingham. Ph.D.

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Abstract

The mechanisms of neural control of human balance, and in particular upright stance, are still not fully understood. Most authors understand balance to be controlled through relatively simple reflex mechanisms, but some groups propose balance is dominated by higher level control.

I develop new semi-automatic techniques which can follow very small changes in muscle length via ultrasonography. I use this technique to uncover a high sensitivity control mechanism in human standing that is more consistent with reflex than higher level control. Further experiments suggest reflex control is present, albeit at a low gain, in a balance control task that is similar to standing, but that higher level control mechanisms dominate. A final investigation into visuo-manual balance suggests that control alternates between actions and sensation which facilitates higher quality sensory feedback.

I hypothesise that balance is maintained by parallel neural pathways. Reflex control operates at low gain to increase the time constant of the human inverted pendulum. This facilitates the operation of a higher level controller that is subject to longer time delays. I speculate that higher level serial ballistic control may enable higher quality feedback than would be possible otherwise.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):