a map of the brain

Smole is a smart cookie. I checked out "motor homunculus in the brain cortex" as per her instructions in her comment, and was completely thrilled with what I found.




The primary motor cortex is one of the principal brain areas involved in motor function. (See blue in Figure 1a on the left)

Every part of the body is represented in the primary motor cortex, and these representations are arranged somatotopically (i.e., organized in a point-to-point representation of the surface of the body)-- the foot is next to the leg which is next to the trunk which is next to the arm and the hand.

The amount of brain matter devoted to any particular body part represents the amount of control that the primary motor cortex has over that body part. For example, a lot of cortical space is required to control the complex movements of the hand and fingers, and relatively less space is required for the trunk or legs, whose muscle patterns are relatively simple.


This disproportionate map of the body in the motor cortex is called the motor homunculus. (See Figure 1b on right)

What an amazing map.. It is a Western diagram of how body parts are linked together, as compared to the Eastern reflexology diagram of the foot in the earlier post.

The next time I grab a pen to write a note, I'm going to spend 10 seconds in awe, and thank God that we're fearfully and wonderfully made.

(Graphics and info from brainconnection.com)

A different representation of sensory and motor homunculus. Click on picture to read captions. Better images found here.


(No wonder lovers like to kiss and hold hands!)