Induction of Motor Programs

To trigger motor programs CBI-2 was intracellularly stimulated during the protraction phase of the motor program at 9 Hz with brief (10 ms) current pulses to elicit one-for-one action potentials. To induce ingestive repetition priming, we stimulated CBI-2 so that ~7 cycles of motor activity were triggered with 30 s between the termination of the retraction phase of one cycle and the initiation of the protraction phase of the following cycle (Friedman and Weiss, 2010). In preparations in which CBI-3 was activated, it was intracellularly stimulated during the protraction phase of the motor program at 15 Hz with brief (10 ms) current pulses to elicit one-for-one action potentials. In preparations in which we triggered more than one series of cycles, we waited at least 1 h in between trials. Previous work has demonstrated that this time period is sufficient to allow effects of repetition priming to dissipate (Perkins et al., 2018).