ray johnstone wrote in message <365bc088.82777392 at news.iinet.com.au>...
>"Richard Norman" <rsnorman at mw.mediaone.net> wrote:
>>>I had long read (and long taught) about the importance of the stretch
>>reflex negative feedback control system in controlling motor activity.
>>>>That is until a herniated disk pressing on L4 and L5 eliminated the
>>reflexes in my right leg as well as cutaneous sense over a large area.
>> I lost a lot of muscle strength and found myself hesitating to put
>>full weight on my leg, as in climbing stairs, but that might have
>>related to reduction in motor activity, not loss of sensory.feedback.
>>I never noticed any problem in motor coordination or control.
>>>>My neurologist claimed that that was well known -- many people
>>function well without these reflexes and also wondered why the
>>stretch reflex was given such prominent attention in teaching about
>>motor control.
>>>>Of course, it does make a might pretty story, whether or not true!
>I think its importance is partly due to the fact that it is the first
>reflex pathway to be described (by Sherrington) in detail.How
>important it is in the grand scheme of the CNS is another matter.
>How can you and your neurologist be so sure about your L4 and 5
>damage? It's hard enough to be sure in an experimental animal, even
>with the pathology done.
>J.R.Johnstone (Ray Johnstone)
The loss of cutaneous sensation along both sides of the lower leg,
definitely crossing the midline, was a strong clue. The MRI scan
showed contact of the bulging disc on both roots also helped.
The loss of reflex was indicated by massive repeated hammering
on my knee which produced no noticeable reaction.
No electrophysiological tests were done.
Fortunately all symptoms spontaneously disappeared within a
few months and, after physical therapy to restore strength and
teach me proper back care, I seem fully recovered.
But I no longer emphasize the importance of the stretch reflex on
motor control in my teaching so emphatically!
