Figure 1.

B50 requires B63 firing to drive motor programs. Single (A) or multicycle (B) programs were elicited by stimulating B50 with brief current pulses at 10 Hz. The protraction phase (marked by white bar below traces) was monitored by intracellular recording of B31/B32 and extracellular recording of the I2 nerve (I2N). The retraction phase (marked by black bar below traces) was monitored by extracellular recording of the buccal nerve 2 (BN2). When B63 was hyperpolarized (gray bar), B31/B32 no longer entered plateau, I2N activity was severely reduced, and BN2 activity was completely blocked. The dashed line marks the level of peak depolarization in B31/B32 under control conditions to facilitate comparison.