Swimming movements elicited by electrical stimulation of turtle spinal cord. I. Low-spinal and intact preparations.

1. Electrical stimulation applied within the dorsolateral funiculus of the spinal cord of an intact, unanesthetized turtle can elicit rhythmic limb movements similar to those observed during swimming. 2. A spontaneous display of hindlimb swimming movements is not observed in adult turtles whose spinal cord is transected at D2. Such swimming movements are observed in these "low-spinal" turtles in response to electrical stimulation applied within the dorsolateral funiculus caudad to the transection. 3. The repetition rate of these swimming movements can be altered by changing stimulus parameters, such as the frequency of electrical pulses. 4. The present results indicate that, in the turtle, a neural pattern generator contributing to the production of hindlimb movements during swimming is located mainly in structures caudad to the cervical enlargement of the spinal cord. These data support the hypothesis that a pattern generator for locomotion is largely resident within the spinal cord.