Meeting Abstract
Mastication is a mammalian motor behavior used to reduce and mix food with saliva before swallowing. During mastication, the jaw moves rhythmically through openings and closings, tracing a three-dimensional path. Variability in these movements results primarily from variation in food properties; however, feedforward and feedback mechanisms work to reduce the variation. Most mastication studies are based upon measurements taken at a finite set of heuristic time points in the continuous movements. This omits considerable information content in the movements. We hypothesize that critical food- and individual-specific variation occurs during times that are not typically analyzed. We employ functional data analysis (FDA) to test this hypothesis. FDA transforms complete movements into basis functions, which serve as observations for statistical analyses. We used masticatory jaw movements from four omnivorous pigs fed three foods, viz., almonds, carrots, and apples. Time series representing jaw movements were provided by Dr. Susan Williams’ lab as part of a collaborative project. Functional analysis of variance (fANOVA) was used to test main effects of individual pig and food and two-way interactions. Results demonstrate that significant differences exist in time points that are rarely if ever analyzed with traditional methods. Thus, FDA is a useful approach for understanding the dynamics of complex, continuous movements in functional morphological and motor control studies.
