0
$\begingroup$

I was looking at cortical homunculus and I realized there are several different pictures and they don't quite agree. For instance:

http://wellbeing.media.mit.edu/2014/02/21/mindfulness-neuroimaging-and-neurofeedback/

http://nawrot.psych.ndsu.nodak.edu/Courses/465Projects11/PLS/4Thesomatosensoryandmotorcortices.htm

One area, for instance, are the feet, which I feel should have a fairly large (not as big as hands) area in the brain, mainly from the personal experience of having more sensations in feet, which like the hands has many nerve endings, though obviously much less fine motor ability. But that's just my speculation, and I like an accurate depiction so I can start from there and make sense of this. Thank you.

$\endgroup$
  • 1
    $\begingroup$ The reason they vary ever-so-slightly is down to a matter of opinion. $\endgroup$ – James Oct 26 '16 at 2:08
2
$\begingroup$

Be sure to distinguish exactly what the diagram is showing. Your first reference is sensory cortex mapping. The second reference is motor cortex mapping. The text of the second reference is admittedly confusing about this, a search for "Wilder Penfield motor cortex" verifies.

It seems reasonable the feet would show sensory response similar to the hands. Stepping on a nail is just about as bad as bumping your hand into one. Motor control is different. Muscles are not all innervated the same. In some of the large muscles, say in the legs, one nerve can control hundreds of cells. In other cases, particularily in the face, one neuron might control only six muscle cells. Thus a greater number of neurons, and a larger portion of the brain, is needed for control in these delicately controlled areas. It would make sense a greater part of our brain would be needed for motor control in our hands versus our feet.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.