Figure 6.

Rhythmic biting induced by contingent food-reward stimulation. A, Autocorrelation analysis (top, raster plots; bottom, corresponding frequency histograms) of 100 successive radula cycles at 1 h after training. In different control (1) and noncontingent (3) animals, bites occurred randomly (histograms not fitted by a Gabor function). In contrast, an animal from the seaweed group (2) expressed rhythmic biting (period of ∼4.8 s) as indicated by the data fit (p < 0.001) with a Gabor function (bold line, bottom). B, Group comparison. The proportion of animals that expressed rhythmic biting was significantly higher in the contingent (Cont.) group than either the control (p < 0.001) or noncontingent (Non-cont.; p < 0.001) groups. Control versus noncontingent, not significant (n.s.).