Fig. 3. Fictive crawling is not inhibited by bath application of 50 µmol l^–1 DA. The fictive crawling motor rhythm is characterized by alternating bursts of action potentials in the dorsal longitudinal muscle excitor DE-3 (the largest unit in the DP nerve) and the circular muscle contractor CV in ganglion 9, with a cycle period of 7–20 s (Eisenhart et al., 2000). (A) Spontaneous fictive crawling activity after a 10 min bath application of 50 µmol l^–1 DA. (B) Spontaneous fictive crawling activity in saline without the amine.