Tuesday, August 11, 2009

Body Movement: Voluntary vs. Involuntary

Not quite that simple, it turns out...

Some body movements have both a reflex component and a voluntary component. Many of them are rhythmic movements such as breathing, chewing, and walking. These movements are produced by neural circuits called central pattern generators. When activated, the neurons in these circuits generate a certain pattern of predetermined neural activity that smoothly co-ordinates the contraction of the many muscles involved in rhythmic activities.

These pattern generators free up the conscious mind so that I don't have to send down a voluntary command every time I want to put one foot in front of the other. In this respect, walking resembles a reflex activity. But I do have to issue voluntary commands when I want to start or stop walking, just as I do to pick up my pace to get across the street when the light turns yellow, or to make that little jump up to the curb on the opposite side, or a small sidestep to avoid a puddle along the way. Thus voluntary commands can also modulate certain reflex movements.

This is the effective compromise between the need to free my overworked and already frenzied mind from repetitive movements, and the need to retain some ability to adjust to changes and obstacles in the environment. Or, allow me to walk and chew gum at the same time.

An intriguing question: What actions are thoughtful, and which are mere reflex? Does my conscious know the reality and can I even tell the difference? How much of my day-to-day is really just pre-programmed knee-jerks, going through the motions?

What do YOU think?

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