Hi Luke. This is a cute question. although not a neuroanatomist I'd like to
further complicate the question.
1. The example is one of a static system. An amputee donning a PTB
prosthetic device obviously places pressure on the tendon while
simultaneously " stretching" the muscle during limb heel contact. Why does
the patient not inhibit quad action?
2. We cannot compare cellular spindle activity in the laboratory for events
occurring in muscle during activity. Many reasons, one of which has to do
with input to the cerebellum from 2 tracts, at least. The DSCT, and ASCT.
The first provide info from, among others, spindle and gto, the latter
provides complicated information to the cerebellum, respectively. the cblm
feed this info to the prefrontal and motor systems. A rather wonderful
example of a feed forward system. (the example you provide is that of a
REFLEX model in movement - a taboo in current thinking)
3. receptive specificity/sensitivity: GTOs are very sensitive pressure
transducers, both in the passive and the ACTIVE state. So in the case of
competing input the amount of pressure and duration may be of importance.
Also II afferents are more complicated: both agonist and antagonist
regulation.
4. GTO are disynaptic ve II which are multi. ? role in speed of input to the
system even in the passive state.
5. Who is to say that the whole muscle is being inhibited/facilitated?
6. The role of the GTO in movement regulation is quite complex.
Joe
Here's something I've been pondering about, but not found a solution
to if anyone can guide me.
W
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