Figure 6.

B20 is not essential for positive biasing. A, Egestive activity was characterized by inducing egestive repetition priming (A1). Preparations were rested for 30 min, and positive biasing was then induced under control conditions (no B20 hyperpolarization) (A2) or with B20 hyperpolarized (A3). B, The B8 firing frequency after positive biasing during the protraction phase of the seventh cycle of activity with and without B20 hyperpolarization. Bottom and top, Dashed lines plot the B8 firing frequency before and after egestive repetition priming (as shown in A1). Bottom, Dashed line indicates the B8 firing frequency during a cycle that is intermediate in nature. Top, Dashed line indicates the B8 firing frequency during a cycle that is egestive. Hyperpolarization of B20 did not decrease the B8 firing frequency (i.e., activity remained egestive) (n = 4). C, The B8 firing frequency after positive biasing during the protraction phase of the seventh cycle of activity with and without B65 hyperpolarization. Hyperpolarization of B65 decreased the B8 firing frequency (n = 5). A–C, Green represents data obtained under control conditions (no hyperpolarization). Blue represents data obtained when neurons were hyperpolarized. *p < 0.05. n.s., Not significant at p > 0.05.