Meeting Abstract
Feeding has been the primary focus of most 3D kinematic studies of cranial function in mammals. Drinking, on the other hand, has received less interest perhaps due to the emphasis on soft tissue movements responsible for liquid transport through the oral cavity. Nevertheless, the opening and closing of the jaw, or gape cycle, is a fundamental component of both feeding and drinking, and thus can be used as a common basis for comparison between the two behaviors. The objective of this study is to compare the dynamics of the gape cycle, characterized by the durations and amplitudes of 3D jaw movements, and relate jaw movements to tongue movements during drinking and feeding in pigs. We hypothesize that the gape cycles will be similar during both behaviors, but that chewing will exhibit higher levels of variability due to the interactions of the teeth and tongue with food. Data were collected from 3-month old pigs feeding on apples or drinking apple juice. The juice was ingested by a sucking mechanism combined with pumping movements of the tongue. Chewing cycles had an extended slow-close phase, reflecting the tooth-food-tooth contact necessary for preparing a bolus while sucking cycles had an extended slow-open phase, which corresponds to tongue protrusion into the fluid. Compared to chewing, sucking showed low amplitudes for all degrees of freedom used (jaw protraction, yaw, and opening). Sucking cycles were shorter than chewing cycles (p<0.001), but had a much higher coefficient of variation (9.47 vs 25.3), suggesting that sucking is not as rhythmic as mammalian chewing. These results provide a context in which to analyze regional tongue movements and deformations relative to the gape cycle.
