1. Descartes

3. Charles Sherrington at 50

4. Sherington’s Physiology, c1900-1945

5. A pool of motor neurons In the spinal cord Serves each muscle These pools form a Topographic map (sort of)

6. Sherrington’s Conceptual masterpiece The Stretch Reflex The sensory element:

7. The Stretch Reflex Circuit

8. Another View of the Stretch Reflex Note that some other system Has to set the initial position Of the limb

9. The Crossed Extension Reflex Involves excitation and Inhibition Activates muscles on both sides of body