Ontogeny of oral function in hamsters (Mesocricetus auratus)
01 Sep 1980-Journal of Morphology (Wiley Subscription Services, Inc., A Wiley Company)-Vol. 165, Iss: 3, pp 237-254
TL;DR: Development of frequent, coordinated macromovements of chewing was associated with the refinement of joint structure and dental occlusion and with the growth of the craniofacial skeleton.
Abstract: The oral apparatus of neonatal and juvenile golden hamsters was investigated by clearing and staining of whole crania, videotaping of behavior, and electromyography of several jaw muscles. Chewing developed during the first postnatal week and matured in the second; however, suckling was still the primary mode of feeding. Micromovements of the jaws occurred early when the osseous skeleton and joints developed. Macromovements correlated well with EMG records and were limited to jaw opening at birth. Muscles of the oral floor generated large bursts of activity during jaw opening and tongue protrusion from 0 days postnatal (dpn), when simple and stereotyped gaping was induced, until 14 dpn, when movements were spontaneous and not stereotyped nor inducible. However, adductor muscle activity was brief, low in amplitude, and primarily involved with jaw stabilization until 4 dpn, when these muscles became active during closing the jaws; closing activity increased in frequency and amplitude until the end of the second week. Development of frequent, coordinated macromovements of chewing was associated with the refinement of joint structure and dental occlusion and with the growth of the craniofacial skeleton. Jaw movements and associated EMG's correlated better with available data on development of neural circuitry than with that for musculoskeletal development.
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TL;DR: Comparison of EMGs between behaviors and between ages allowed interpretation of the degree of contunity of muscular activity across the suckling-to-chewing transition to be interpreted.
Abstract: During mammalian ontogeny, there is a transition from suckling to the chewing of food. The question was asked: Is suckling a neuromuscular precursor to chewing, or are suckling and chewing independent systems? Electromyograms (EMGs) were recorded in rat pups of ages 6, 9, 12, 15, 18, and 21 days from the superficial masseter, anterior digastric, sternohyoideus, and genioglossus muscles during suckling and chewing. The EMG patterns of the 3 components of suckling behavior (nipple attachment, rhythmic sucking and the stretch response) are distinctive from one another and reflect the musculoskeletal biomechanics of suckling. Chewing EMGs are present by 12 days of age and attain the adult pattern by 18-21 days of age. During nipple attachment, pups exhibit a motor pattern that is similar to that of adult chewing, but other aspects of suckling differ from chewing in some EMG features. Comparison of EMGs between behaviors and between ages allowed interpretation of the degree of contunity of muscular activity across the suckling-to-chewing transition.
136 citations
TL;DR: It is suggested that the relatively fixed coordinative framework for chewing exhibited by these children would not be suitable for adaptation to speech movements, which have been shown to rely on a much more variable and adjustable coordinative organization.
Abstract: Green, Jordan R., Christopher A. Moore, Jacki L. Ruark, Paula R. Rodda, Wendy T. Morvee, and Marcus J. VanWitzenburg. Development of chewing in children from 12 to 48 months: longitudinal study of ...
135 citations
Cites background from "Ontogeny of oral function in hamste..."
...…1974; McNamara 1974), rats which were found to be consistent with each other, demonstrated (Westneat and Hall 1992), dogs (Iinuma et al. 1991), and that the basic chewing pattern of reciprocally activated antagonistic hamsters (Lakars and Herring 1980).muscle groups is established by 12 mo of age....
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...…movements, in muscle activation patterns through development have been which have been shown to rely on a much more variable and correlated with ontogenetic changes in skull /mandibular size adjustable coordinative organization. and geometry (Herring 1985; Lakars and Herring 1980; Na- kata 1981)....
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TL;DR: Throughout ontogeny there is a reciprocal relation between morphology and behavior, and masticatory performance depends on structure at any given stage, it also has profound effects on further musculoskeletal growth and differentiation.
Abstract: Movements of the oral apparatus begin during the fetal period and develop in a consistent order. Jaw openingappears first, followed by active jaw closure and tongue movements, lip movements, sucking, and finally masticatory movements. The later developing movements appear prenatally in precocious mammals such as guinea pigs and sheep, but are postnatal in altricial mammals such as rats, hamsters and rabbits. The orderly development of oral behavior is probably related to the progressive maturation of the nervous system and neuromuscular connections. Most newborn mammals feed exclusively bysuckling, a combination of the tongue working against the nipple and negative pressure at the back of the oral cavity. Thetransition from suckling to mastication is gradual and involves considerable learning. In at least one species, the domestic pig, infant animals chew using a somewhat different muscular contraction pattern from that of adults. Age changes in muscle action lines are the most likely explanation for this difference. After being established in infancy, the process of mastication undergoes only minor changes in rate and relative muscle activity during the juvenile period. Throughout ontogeny there is a reciprocal relation between morphology and behavior. While masticatory performance depends on structure at any given stage, it also has profound effects on further musculoskeletal growth and differentiation.
132 citations
Book•
01 Jan 2011
TL;DR: Hallgrimsson and Hall as mentioned in this paper discussed the link between phenotype and genotype in development and evolution, and proposed an approach to link phenotype and phenotype in the context of development, and discussed the developmental route to functional integration.
Abstract: Epigenetics: Linking Genotype and Phenotype in Development and Evolution 1. Introduction: Emergent Properties and the Phenotype Hallgrimsson and Hall Historical and Philosophical Foundations 2. Historical Foundations Brian K. Hall 3. Heuristic Reductionism and the Relative Significance of Inheritance James Grisemer Approaches to Epigenetics 4. Genomic imprinting Vett Lloyd 5. Methylation Mapping in Humans Christoph Grunau, Montpellier 6. Asexuality and Epigenetic Variation Root Gorelick, Manfred Laubichler and Rachel Massicotte 7. Preformation and the Humpty Dumpty Problem Ellie Larsen 8. A Principle of Developmental Inertia Allesandro Minelli Epigenetics of Vertebrate Organ Development 9. Nervous System Development Carol Schuurmans 10. Morphogenesis of pigment patterns Lennart Olsson 11. Interactions of the Cardiac Neural Crest Margaret Kirby 12. Bone and Cartilage Development Tamara Franz-Odendaal 13. Muscle-Bone Interactions and the Development of Skeletal Phenotype Sue Herring 14. Apical Ectoderm in the Developing Vertebrate Limb Cooper, L.N, Armfield, B.A., J.G.M. Thewissen 15. Role of Skeletal Muscle in the Shaping of Organs, Tissues and Cell Fate Choices Boris Kablar Epigenetics in Evolution and Disease 16. Integration, Complexity and Evolvability of the Head Dan Lieberman 17. Epigenetic interactions: The developmental route to functional integration Miriam Leah Zelditcha and Donald L. Swiderski 18. Epigenetic Contributions to Adaptive Radiation Susan Foster 19. Learning, Developmental Plasticity, and the Rate of Morphological Evolution Rich Palmer and Chris Neufeld 20. Epigenetics: Adaptation or Contingency Thomas Hansen 21. Dysmorphology Joan Richtsmeier 22. Human Disease Peter Gluckman 23. Epigenetics: The Context of Development Hallgrimsson and Hall
110 citations
TL;DR: The changes in opening speed, gape, and chewing frequency are consistent with earlier predictions from the morphological changes, and so is the extra activity needed to chew hard food.
Abstract: To investigate the biomechanical effects of juvenile growth changes in the rabbit masticatory apparatus a comparison was made of mastication in just-weaned and adult animals. Mandibular movements in two planes were registered by cineradiography. Masticatory muscle activity was recorded by fine-wire electromyography. The same pattern of unilateral mastication was present in the two ages. The most important changes in the jaw movements are 1) a decrease of jaw opening speed and chewing frequency and an increase in jaw opening time, 2) a decrease in maximum gape in soft food and an unaltered gape in small-particle hard food, and 3) an increase in lateral jaw excursion, mainly due to a more pronounced movement of the jaw to the balancing side (lingual phase). The contraction patterns were basically similar in the two ages. The higher chewing frequency in young animals was attained by a larger degree of overlap between opening and closing muscle activities. Young animals used relatively more EMG activity to chew hay, the hardest food. The changes in opening speed, gape, and chewing frequency are consistent with earlier predictions from the morphological changes, and so is the extra activity needed to chew hard food. The increase in lateral excursion was not predicted. It is suggested to be caused by cheek teeth wear, making possible smooth occlusal guidance of the jaw at the balancing side. Some of the changes in juvenile morphology can be viewed as adaptations to a changing diet.
108 citations
References
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TL;DR: Alcohol treatment in addition to formalin fixation does not affect results with this method, it should be useful to researchers who want to study the cartilage or cartilaginous skeletons in museum specimens, which are routinely fixed in formalin and stored in alcohol.
Abstract: Preparation of small vertebrates cleared after alcian blue staining of cartilage is facilitated by trypsin digestion. Specimens are fixed in formation, washed, skinned, and eviscerated. After staining in a solution of alcian blue in acetic acid-alcohol for 24-48 hours, they are transferred to water through graded alcohols. Excess alcian blue is removed over a period of up to three weeks by changes every 2-3 days of 1% trypsin in approximately one-third-saturated sodium borate. Bony tissues may be stained after this in a solution of alizarin red S in 0.5% KOH. Specimens are bleached if necessary and dehydrated through graded KOH-glycerine mixtures for storage in glycerine. Since alcohol treatment in addition to formalin fixation does not affect results with this method, it should be useful to researchers who want to study the cartilage or cartilaginous skeletons in museum specimens, which are routinely fixed in formalin and stored in alcohol.
1,246 citations
TL;DR: A study has been made of the formation of synapses in developing striated muscles which receive either a focal (the rat hemidiaphragm) or a distributed innervation using histological, ultrastructural and electrophysiological techniques.
Abstract: 1. A study has been made of the formation of synapses in developing striated muscles which receive either a focal (the rat hemidiaphragm) or a distributed (the avian anterior latissimus dorsi) innervation using histological, ultrastructural and electrophysiological techniques.
2. In the developing diaphragm only a single synaptic contact was initially established at random along the length of the short (300 μm) myotubes by a single axon; in the developing ALD more than one synaptic contact could be established initially along the length of the long (2500 μm) myotubes by axons, but the distance between these was never less than 170 μm.
3. Each synapse established by the initial axonal contact in either the diaphragm or the ALD subsequently received a multiple innervation from further exploring axons in the muscles, and all such additional innervation of muscle cells was constrained to the sites of the initial synaptic contacts; this multiple innervation of synaptic sites was lost in the subsequent 4 weeks.
4. It is suggested that the axon forming the initial synaptic contact on myotubes induces a property over an adjacent length of myotube which makes its membrane refractory to synapse formation over this length; this characteristic length is longer for axons forming a focal innervation than it is for those forming distributed innervation.
465 citations
385 citations
TL;DR: This review will attempt to synthesize the results of the major experimental studies as well as place into sharper focus some of the new problems which have stemmed from electron microscopic investigations of the past decade.
Abstract: Regeneration of skeletal muscle has often been described during the past century, but only during the past 25 years have attempts been made to uncover causal mechanisms underlying the process. The historical and classical histological aspects of skeletal muscle regeneration have been reviewed several times (Studitsky and Striganova, '51; Godman, '57; Field, '60; Betz et al., '66). Here I shall attempt to synthesize the results of the major experimental studies as well as place into sharper focus some of the new problems which have stemmed from electron microscopic investigations of the past decade. With respect to both control mechanisms and certain morphological aspects of regeneration, considerable confusion has reigned in the past because events occurring in the repair of damaged mammalian muscle have been equated with those which take place in the regenerating amphibian limb. One of the major functions of this review will be to point out where similarities between these two processes may exist and where the systems are not directly comparable. The review will conclude with a short discussion about the clinical implications of recent progress in the field of muscle regenera tion.
354 citations
TL;DR: The conclusion is made that in the rat fetus local complex patterns are built up from less complex units, resembling mature and fully integrated action patterns.
Abstract: I. The characteristics of prenatal spontaneous activity of rat fetuses of 16 through 20 days of gestation, and the development of responses to cutaneous stimulation are discussed and tabulated. In early fetuses of 16 and 17 days, only few activity bursts occur between long intervals of inactivity. The frequency of activity bursts increases greatly at day 18 and attains a peak at this stage, whereupon it declines to a lower level from day 19 through term. 2. Qualitatively, the movements appear to be unintegrated. Three types of activity have been distinguished: Total, generalized or mass movements, when all parts that are capable of movements participate; regional when only one body region such as the head and forelimbs are in motion, and local movements of single parts. In the earliest stage, only head and forelimb movements are observed. There is a gradual extension of motility in rostro-caudal and proximodistal direction, but there are exceptions to this rule. The movements in the rat fetus seem to be more smooth compared with those of the chick embryo where the movements are more jerky. 3. Our recordings show that no clear, or one-to-one correlation exists between fetal activity and uterine contractions. Amnion contractions do not occur in the rat fetus. 4. The first evoked responses in the rat fetus are interpreted as an incipient total or regional pattern. In later stages of development, discrete, low-amplitude unintegrated local responses are identifiable. At 17 and 18 days the local responses are frequently combined with regional and total mass body movements, but by day 19, total movements are less frequently elicited, and the local responses are more complex, resembling mature and fully integrated action patterns. The conclusion is made that in the rat fetus local complex patterns are built up from less complex units. 5. Spontaneous motility in other mammalian embryos and the origin of integrated specialized local action patterns are discussed in relation to the development of the structure and organization of the spinal cord.
236 citations