The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy.
All mammalian infants suckle, a fundamentally different process than drinking in adults. Infant mammal oropharyngeal anatomy is also anteroposteriorly compressed and becomes more elongate postnatally. While suckling and drinking require different patterns of muscle use and kinematics, little insight exists into how the neuromotor and anatomical systems change through the time that infants suckle. We measured the orientation, activity and contractile patterns of five muscles active during infant feeding from early infancy until weaning using a pig model. Muscles not aligned with the long axis of the body became less mediolaterally orientated with age. However, the timing of activation and the contractile patterns of those muscles exhibited little change, although variation was larger in younger infants than older infants. At both ages, there were differences in contractile patterns within muscles active during both sucking and swallowing, as well as variation among muscles during swallowing. The changes in anatomy, coupled with less variation closer to weaning and little change in muscle firing and shortening patterns suggest that the neuromotor system may be optimized to transition to solid foods. The lesser consequences of aspiration during feeding on an all-liquid diet may not necessitate the evolution of variation in neuromotor function through infancy.
Mayerl CJ; Steer KE; Chava AM; Bond LE; Edmonds CE; Gould FDH; Stricklen BM; Hieronymous TL; German RZ
Proceedings of the Royal Society B. Biological Sciences
2021
2021-03-10
Journal Article
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The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy.
ontogeny; mammal; feeding; swallowing; ANATOMY; EMG; DEGLUTITION; PHYSIOLOGY; HYOID bone; INFANTS; MAMMAL anatomy; MOTOR unit
All mammalian infants suckle, a fundamentally different process than drinking in adults. Infant mammal oropharyngeal anatomy is also anteroposteriorly compressed and becomes more elongate postnatally. While suckling and drinking require different patterns of muscle use and kinematics, little insight exists into how the neuromotor and anatomical systems change through the time that infants suckle. We measured the orientation, activity and contractile patterns of five muscles active during infant feeding from early infancy until weaning using a pig model. Muscles not aligned with the long axis of the body became less mediolaterally orientated with age. However, the timing of activation and the contractile patterns of those muscles exhibited little change, although variation was larger in younger infants than older infants. At both ages, there were differences in contractile patterns within muscles active during both sucking and swallowing, as well as variation among muscles during swallowing. The changes in anatomy, coupled with less variation closer to weaning and little change in muscle firing and shortening patterns suggest that the neuromotor system may be optimized to transition to solid foods. The lesser consequences of aspiration during feeding on an all-liquid diet may not necessitate the evolution of variation in neuromotor function through infancy.
Mayerl CJ; Steer KE; Chava AM; Bond LE; Edmonds CE; Gould FDH; Stricklen BM; Hieronymous TL; German RZ
Proceedings of the Royal Society B. Biological Sciences
2021
2021-03-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
journalArticle
<a href="http://doi.org/10.1098/rspb.2021.0052" target="_blank" rel="noreferrer noopener">10.1098/rspb.2021.0052</a>
Changes in the coordination between respiration and swallowing from suckling through weaning.
aerodigestive; chin-tuck maneuver; deglutition; dysphagia; food transport; mammal; maturation; preterm; solid food; thickened infant formula; weaning
All mammals undergo weaning from milk to solid food. This process requires substantial changes to mammalian oropharyngeal function. The coordination of swallowing and respiration is a crucial component of maintaining airway function throughout feeding and matures over infant development. However, how this coordination is affected by weaning is unknown. In this study, we ask how changes in posture, neural maturation and food properties associated with the weaning affect coordination of respiration and swallowing in a validated infant pig model. We recorded seven piglets feeding before and during the weaning age with liquid milk in a bottle and in a bowl, and solid feed in a bowl. Using videofluoroscopy synchronized with respiration, we found (i) the delay in the onset of inspiration after swallowing does not change with head position, (ii) the delay is different between solid food and bowl drinking at the same age and (iii) the delay increases over time when bottle feeding, suggesting a maturational effect. Significant changes in aerodigestive coordination occur prior to and post-weaning, resulting in distinctive patterns for liquid and solid food. The interplay of maturational timelines of oropharyngeal function at weaning may serve as a locus for behavioural and life-history plasticity.
Bond Laura E; Mayerl Christopher J; Stricklen Bethany M; German Rebecca Z; Gould Francois D H
Biology letters
2020
2020-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
journalArticle
<a href="http://doi.org/10.1098/rsbl.2019.0942" target="_blank" rel="noreferrer noopener">10.1098/rsbl.2019.0942</a>
Evidence from surface microscopy for recognition of fleshy and tendinous muscle insertion in extant vertebrate femora: implications for muscle reconstruction in fossils
attachment sites; bird; birds neornithes; bone-tendon; Dinosaur; entheseal changes; evolution; Life Sciences & Biomedicine - Other Topics; mammal; mechanical load; muscle; musculoskeletal stress markers; Paleontology; pelvic musculature; reptile; soft-tissues; tendon; upper-limb
Recognition of muscle attachment sites and their modification has been an important tool in anthropologic and paleontologic research, but has been compromised by limited ability to recognise sites of tendinous attachments. We investigated bone-tendon (three sites) and bone-muscle (six sites) interfaces in six pairs of femora across a broad taxonomic spectrum of higher amniote archosaurs (both recent and fossil) by epi-illumination microscopy. Direct fleshy and indirect tendinous muscle attachments were identified by dissection of fresh specimens and examination of fossils and the surface microscopic changes identified at those locations. Examination revealed bone modifications specific to each type of muscle insertion, allowing them to be identified and distinguished. Application of a surface microscopy technique not only permits more confident localisation of tendinous attachments, but for the first time allows recognition of sites of direct fleshy muscle attachments - in a reproducible manner across phylogenetic lines.
Rothschild B M; Wilhite D R; McLeod D S; Ting H
Historical Biology
2016
2016-08
Journal Article
<a href="http://doi.org/10.1080/08912963.2015.1049163" target="_blank" rel="noreferrer noopener">10.1080/08912963.2015.1049163</a>
Scaling of the marsupial middle ear and its functional significance
absolute; allometry; auditory characteristics; evolution; hearing; hearing sensitivity; impedance; mammal; marsupial; middle ear; mongolian gerbil; monodelphis-domestica; primitive mammals; pure-tone thresholds; size; trichosurus-vulpecula; Zoology
The marsupial middle ear performs an anatomical impedance matching for acoustic energy travelling in air to reach the cochlea. The size of the middle ear sets constraints for the frequencies transmitted. For generalized placental mammals, it has been shown that the limit for high-frequency hearing can be predicted on the basis of middle ear ossicle mass, provided that the ears fulfil requirements of isometry. We studied the interspecific size variation of the middle ear in 23 marsupial species, with the following measurable parameters: skull mass, condylobasal length, ossicular masses for malleus, incus and stapes, tympanic membrane area, oval window area, and lever arm lengths for malleus and incus. Our results show that the middle ear size grows with negative allometry in relation to body size and that the internal proportions of the marsupial middle ear are largely isometric. This resembles the situation in placental mammals and allows us to use their isometric middle ear model to predict the high-frequency hearing limit for marsupials. We found that the isometry model predicts the high-frequency hearing limit for different marsupials well, indicating that marsupials can be used as auditory models for general therian mammalian hearing. At very high frequencies, other factors, such as the inner ear, seem to constrain mammalian hearing.
Nummela S; Sanchez-Villagra M R
Journal of Zoology
2006
2006-10
Journal Article
<a href="http://doi.org/10.1111/j.1469-7998.2006.00126.x" target="_blank" rel="noreferrer noopener">10.1111/j.1469-7998.2006.00126.x</a>