FURTHER ANALYSES OF REFLEX MOVEMENTS IN THE HIND LIMBS OF THE TERRAPIN, PSEUDEMYS-SCRIPTA-ELEGANS

1. Studies of the control of reflex (scratching) movements of the rear limb of the terrapin were made on spinal preparations and chronic preparations where the spine was transected at the D3-D4 levels. 2. The mechanism in the spinal cord which controls this movement does not obviously compensate either for external frictional forces acting on the limb or to effects of gravity if the preparation is placed in a non-horizontal position. 3. EMG patterns are not modified if an obstacle prevents the limb from reaching its target. 4. Peripheral information is not continuously used to control this movement. The control mechanism is probably a generator which can adjust to different stimulus places. 5. Extensor activity can be inhibited by afferent inflow from the limb. 6. Generation of new cycles of movement in response to a single stimulus can be inhibited by afferent inflow. © 1979 Springer-Verlag.