Meeting Abstract
S2.5 Tuesday, Jan. 4 Patterns of functional integration in the mammalian masticatory apparatus VINYARD, CJ*; DOHERTY, AH; WALL, CE; WILLIAMS, SH; ROSS, CF; HERRING, SW; CROMPTON, AW; HYLANDER, WL; NEOUCOM; NEOUCOM; Duke Univ; Ohio Univ; Univ of Chicago; Univ of Washington; Harvard Univ; Duke Univ cvinyard@neoucom.edu
Jaw-muscle recruitment plays a key role in the complex 3D kinetics of the mandible that occlude the teeth and break down foods during chewing. The assembly of electromyographic (EMG) data across mammals in the Feeding Experiments End-user Database (FEED) allows us to begin quantifying how jaw-muscle recruitment has been integrated with bone, muscle and dental form during mammalian evolution. A long-standing hypothesis in studies of mammalian mastication argues that musculoskeletal form has changed markedly during evolution while jaw-muscle activation has remained relatively similar. If morphology has evolved within this conserved behavioral framework, then we predict little integration between jaw-muscle EMGs and musculoskeletal form as EMGs should exhibit limited variation within orders. To examine these relationships, we compare jaw-muscle EMG data to musculoskeletal measures of the masticatory apparatus, focusing on the mammalian groups best represented in FEED. At present, primates are well represented allowing detailed study of this group. Similar analyses of ungulates and marsupials will be conducted. Contrary to the prediction of little association, we find strong correlations between jaw-muscle EMGs and masticatory apparatus shapes in primates. These associations fit in vivo findings linking jaw loading to morphologies providing increased load resistance. In primates, we identify a conserved functional module related to vertical force production during mastication that incorporates both neuromuscular activation and musculoskeletal form. Based on these initial analyses, jaw-muscle activity patterns can be an integrated and evolving part of the mammalian masticatory apparatus. Supported by NSF.
