Grant sponsor: NIH; Grant numbers: DC03604, DC009980, DE007309.
Regional Variation in Geniohyoid Muscle Strain During Suckling in the Infant Pig
Version of Record online: 1 MAY 2012
© 2012 WILEY PERIODICALS, INC.
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology
Volume 317, Issue 6, pages 359–370, July 2012
How to Cite
How to cite this article: 2012. Regional variation in geniohyoid muscle strain during suckling in the infant pig. J. Exp. Zool. 317A:359–370., , , .
- Issue online: 9 JUL 2012
- Version of Record online: 1 MAY 2012
- Manuscript Accepted: 14 MAR 2012
- Manuscript Revised: 12 MAR 2012
- Manuscript Received: 20 JAN 2012
- NIH. Grant Numbers: DC03604, DC009980, DE007309
The geniohyoid muscle (GH) is a critical suprahyoid muscle in most mammalian oropharyngeal motor activities. We used sonomicrometry to evaluate regional strain (i.e., changes in length) in the muscle origin, belly, and insertion during suckling in infant pigs, and compared the results to existing information on strain heterogeneity in the hyoid musculature. We tested the hypothesis that during rhythmic activity, the GH shows regional variation in muscle strain. We used sonomicrometry transducer pairs to divide the muscle into three regions from anterior to posterior. The results showed differences in strain among the regions within a feeding cycle; however, no region consistently shortened or lengthened over the course of a cycle. Moreover, regional strain patterns were not correlated with timing of the suck cycles, neither (1) relative to a swallow cycle (before or after) nor (2) to the time in feeding sequence (early or late). We also found a tight relationship between muscle activity and muscle strain, however, the relative timing of muscle activity and muscle strain was different in some muscle regions and between individuals. A dissection of the C1 innervations of the geniohyoid showed that there are between one and three branches entering the muscle, possibly explaining the variation seen in regional activity and strain. In combination, our findings suggest that regional heterogeneity in muscle strain during patterned suckling behavior functions to stabilize the hyoid bone, whereas the predictable regional strain differences in reflexive behaviors may be necessary for faster and higher amplitude movements of the hyoid bone. J. Exp. Zool. 317A:359–370, 2012. © 2012 Wiley Periodicals, Inc.