Meeting Abstract
Most mammals are characterized by a unique form of food processing (i.e., mastication) that is based on rhythmic 3-dimensional movements of the jaw allowing unilateral tooth occlusion. Low variability in jaw movements during mastication is thought to minimize energy expenditure to meet the higher energetic demands of mammalian metabolism. However, food properties vary immensely and sensorimotor integration within the oral cavity ensures that jaw movements are flexible (i.e., variable) enough to allow different food to be processed. Accordingly, in dietary generalists, the morphology of the feeding system typically supports a wide range of jaw movements responding changes in food properties. In contrast, organisms that are specialized for a narrow diet are typically characterized by morphological adaptations of the feeding system (e.g., restricted temporomandibular joints) that may limit the range of feeding movements that can occur. The objective of this study is to investigate the extent to which a model dietary specialist (Goat, Capra hircus) is able to alter jaw movements in response to different foods. Using biplanar fluoroscopy, 3D kinematics and temporal characteristics of the gape cycle are compared between two types of food: chow and dry leaves. Results indicate that jaw movements are significantly different in amplitude (e.g., mediolateral rotation of the lower jaw at the condyle) and timing (e.g., power stroke duration) when processing different foods. This suggests that (i) the specialized feeding morphology of goats allows flexible jaw movements, and (ii) sensorimotor integration in the oral cavity plays an important role in the neuromotor control of feeding movements, even in dietary specialists.
