Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: billross477 on 22/12/2010 01:26:51
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Could the infant step reflex be evidence of a spinal central pattern generator present at birth?
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Hi Bill,
I think you might want to give a bit more information on what you mean by a pattern generator. I am aware of one type, but it may not be what you have in mind.
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I am referring to a CPG in the spinal cord that regulates the alternating excitation/inhibition cycle of the flexion/extension pairings of leg musculature.
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Bill - locomotion like movement has been shown to be linked to a spinal central pattern generator in accident victims with spinal cord injury. I believe areas of the spinal column were artificially stimulated and in some circumstances the reaction of the motor groups of the leg were similar to walking. I will dig out references and forward them.
And I think the motor impulses generated are even more complex than just alternating tension in large flexor/extensor, but are combinations from the hips and pelvis down to the foot.
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Certainly there is great complexity. There is need to control rate as well as magnitude of contraction, reciprocal inhibition, etc.
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I remember some psych experiments where they would sever the spinal cord on cats.
Put them on a treadmill (with a harness).
& they would walk, although I don't think they were capable of supporting their weight.
Most animals can get up and walk within the first hour after birth, also indicating an innate quality of walking. Birds are bipedal, and can also walk soon after birth.
Reflexes certainly aid with the cadence of walking. However, there is also a certain amount of balance that needs to be acquired, especially for humans.