Meeting Abstract
56.7 Sunday, Jan. 5 15:00 Can we predict mandibular kinematics from patterns of EMG activity in primates? IRIARTE-DIAZ, J.*; ROSS, C.F.; Univ. of Chicago; Univ. of Chicago josdiiri@gmail.com
The muscular system that controls mandible movement in mammals is highly redundant and morphologically complex. For example, for a particular mandibular motion, there are multiple ways that a set of muscles can be activated to produce a desired movement. However, little work has quantitatively evaluated how differences in patterns of muscle activation relate to differences in mandibular movement. Using a large dataset of simultaneously recorded 3D mandible kinematics and muscle activation patterns, we investigated the relationship between these factors in three species of non-human primates (macaques, capuchin monkeys, and baboons). We found that each species studied used different strategies to modulate lateral mandible displacement. Capuchin monkeys used differences in timing and magnitude of activity between working- and balancing-side muscles. Baboons used differences in magnitude but not in timing of muscle activity. Macaques presented strong differences between individuals in their modulation of lateral mandible movement, with some individual using differences in timing of activity while other individuals used differences in magnitude of activity between working and balancing side. After controlling for these confounding effects we found weak but significant relationships between the timing of peak muscle activity and magnitude between working and balancing sides and the amount of lateral displacement during feeding. We suggest that mandible kinematics can be predicted from patterns of EMG activity. However, to further improve our understanding of motor control during feeding in primates, we still need to investigate how species-specific and individual differences in morphological and physiological constraints, such as differences in articular morphology or muscle architecture, affect the modulation of mandibular movement.
