ABSTRACT
Twenty-eight toads (B. marinus) were de-afferentated by severing all spinal dorsal roots.
Every animal made locomotory movements of one kind or another. The normal diagonal pattern was observed fairly often; and, once initiated, this pattern was usually maintained until the animal stopped walking.
When a toad made any protraction movement following three steps of the normal pattern, then the fourth step was the appropriate step for the sequence in 66% of cases. When the preceding steps followed the normal pattern, the fifth step was correct in 67% of cases; the sixth in 62%; the seventh in 81% and the eighth in 41%. Random movement predicts 25% in all these cases.
It is concluded that spinal afferents are not necessary for the co-ordination of diagonal locomotion.
Dedicated, in Memoriam, to Donald M. Wilson, our academic father and grandfather. He dared: in the secrets of nature, in the wildness of nature, and in man’s nature.
