Publications by authors named "Nicholas J Gidmark"

13 Publications

  • Page 1 of 1

The bite force-gape relationship as an avenue of biomechanical adaptation to trophic niche in two salmonid fishes.

J Exp Biol 2020 10 29;223(Pt 20). Epub 2020 Oct 29.

Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA.

All skeletal muscles produce their largest forces at a single optimal length, losing force when stretched or shortened. In vertebrate feeding systems, this fundamental force-length relationship translates to variation in bite force across gape, which affects the food types that can be eaten effectively. We measured the bite force-gape curves of two sympatric species: king salmon () and pink salmon (). Cranial anatomical measurements were not significantly different between species; however, peak bite forces were produced at significantly different gapes. Maximum bite force was achieved at 67% of maximum gape for king salmon and 43% of maximum gape for pink salmon. This may allow king salmon to use greater force when eating large or elusive prey. In contrast, pink salmon do not require high forces at extreme gapes for filter feeding. Our results illustrate that the bite force-gape relationship is an important ecophysiological axis of variation.
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http://dx.doi.org/10.1242/jeb.223180DOI Listing
October 2020

XROMM and diceCT reveal a hydraulic mechanism of tongue base retraction in swallowing.

Sci Rep 2020 05 19;10(1):8215. Epub 2020 May 19.

Department of Organismal Biology & Anatomy, The University of Chicago, Chicago, IL, 60637, USA.

During primate swallowing, tongue base retraction (TBR) drives the food bolus across the oropharynx towards the esophagus and flips the epiglottis over the laryngeal inlet, protecting against penetration and aspiration of food into the airway. Despite the importance of TBR for swallowing performance, the mechanics of TBR are poorly understood. Using biplanar videoradiography (XROMM) of four macaque monkeys, we tested the extrinsic muscle shortening hypothesis, which posits that shortening of the hyoglossus and styloglossus muscles pulls the tongue base posteriorly, and the muscular hydrostat or intrinsic tongue muscle hypothesis, which suggests that, because the tongue is composed of incompressible fluid, intrinsic muscle shortening increases tongue length and displaces the tongue base posteriorly. Our data falsify these hypotheses. Instead we suggest a novel hydraulic mechanism of TBR: shortening and rotation of suprahyoid muscles compresses the tongue between the hard palate, hyoid and mouth floor, squeezing the midline tongue base and food bolus back into the oropharynx. Our hydraulic mechanism is consistent with available data on human tongue swallowing kinematics. Rehabilitation for poor tongue base retraction might benefit from including suprahyoid muscle exercises during treatment.
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http://dx.doi.org/10.1038/s41598-020-64935-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7237434PMC
May 2020

Pharyngeal Jaws Converge by Similar Means, Not to Similar Ends, When Minnows (Cypriniformes: Leuciscidae) Adapt to New Dietary Niches.

Integr Comp Biol 2019 08;59(2):432-442

Department of Biology, Knox College, Galesburg, IL, USA.

Convergent evolution is at the forefront of many form-function studies. There are many examples of multiple independent lineages evolving a similar morphology in response to similar functional demands, providing a framework for testing hypotheses of form-function evolution. However, there are numerous clades with underappreciated convergence, in which there is a perceived homogeneity in morphology. In these groups, it can be difficult to investigate causal relationships of form and function (e.g., diet influencing the evolution of jaw morphology) without the ability to disentangle phylogenetic signal from convergence. Leuciscids (Cypriniformes: Leuciscidae; formerly nested within Cyprinidae) are a species-rich clade of fishes that have diversified to occupy nearly every freshwater trophic niche, yet are considered to have relatively low morphological diversity relative to other large freshwater clades. Within the North American leuciscids, many genera contain at least one herbivore, insectivore, and larvaphage. We created 3D models from micro-computed tomography scans of 165 leuciscid species to measure functionally relevant traits within the pharyngeal jaws of these fishes. Using a published phylogeny, we tested these metrics for evolutionary integration, phylogenetic signal, and correlation with diet. Measurements of the pharyngeal jaws, muscle attachment areas, and teeth showed strong positive evolutionary correlation with each other and negative evolutionary correlation with measurements of the inter-ceratobranchial ligament (ICB ligament). Using diet data from published literature, we found extensive dietary convergence within Leuciscidae. The most common transitions we found were between herbivorous and invertivorous taxa and between insectivore types (aquatic vs. terrestrial). We document a trade-off in which herbivorous leuciscids have large teeth, short ICB ligaments, and large muscle attachment areas, whereas insectivorous leuciscids showed the opposite pattern. Inverse patterns of morphological integration between the ICB ligament the rest of the pharyngeal jaw correspond this dietary trade-off, which indicates that coordinated evolution of morphological traits contributes to functional diversity in this clade. However, these patterns only emerge in the context of phylogeny, meaning that the pharyngeal jaws of North American leuciscids converge by similar means (structural changes in response to dietary demands), but not necessarily to similar ends (absolute phenotype).
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http://dx.doi.org/10.1093/icb/icz090DOI Listing
August 2019

Evidence of a tunable biological spring: elastic energy storage in aponeuroses varies with transverse strain in vivo.

Proc Biol Sci 2019 04;286(1900):20182764

4 Department of Ecology and Evolutionary Biology, Brown University , Providence, RI 02912 , USA.

Tendinous structures are generally thought of as biological springs that operate with a fixed stiffness, yet recent observations on the mechanical behaviour of aponeuroses (broad, sheet-like tendons) have challenged this general assumption. During in situ contractions, aponeuroses undergo changes in both length and width and changes in aponeuroses width can drive changes in longitudinal stiffness. Here, we explore if changes in aponeuroses width can modulate elastic energy (EE) storage in the longitudinal direction. We tested this idea in vivo by quantifying muscle and aponeuroses mechanical behaviour in the turkey lateral gastrocnemius during landing and jumping, activities that require rapid rates of energy dissipation and generation, respectively. We discovered that when aponeurosis width increased (as opposed to decreased), apparent longitudinal stiffness was 34% higher and the capacity of aponeuroses to store EE when stretched in the longitudinal direction was 15% lower. These data reveal that biaxial loading of aponeuroses allows for variation in tendon stiffness and energy storage for different locomotor behaviours.
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http://dx.doi.org/10.1098/rspb.2018.2764DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6501694PMC
April 2019

Evolution of skeletal and muscular morphology within the functionally integrated lower jaw adduction system of sculpins and relatives (Cottoidei).

Zoology (Jena) 2018 08 30;129:59-65. Epub 2018 Jun 30.

Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA; Department of Biology, Knox College, Galesburg, IL 61401, USA.

Vertebrate lever mechanics are defined by the morphology of skeletal elements and the properties of their muscular actuators; these metrics characterize functional diversity. The components of lever systems work in coordination ("functional integration") and may show strong covariation across evolutionary history ("evolutionary integration"), both of which have been hypothesized to constrain phenotypic diversity. We quantified evolutionary integration in a functionally integrated system - the lower jaw of sculpins and relatives (Actinopterygii: Cottoidei). Sculpins primarily rely on suction feeding for prey capture, but there is considerable variation in evasiveness of their prey, resulting in variation in anatomy of the lower jaw-closing mechanism. We used functionally-relevant linear measurements to characterize skeletal and muscular components of this system among 25 cottoid species and two outgroup Hexagrammoidei (greenling) species. We quantified evolutionary covariation and correlation of jaw-closing mechanical advantage (i.e., skeletal leverage) and muscle architecture (i.e., gearing) by correlating phylogenetically independent contrasts and fitting phylogenetically corrected generalized least squares models. We found no evidence of evolutionary covariation in muscle architecture and skeletal leverage. While we found a positive evolutionary correlation between out-lever length and adductor muscle fiber length, there was no significant evolutionary correlation between in-lever length and adductor muscle fiber length. We also found a positive evolutionary correlation between in- and out-lever lengths. These results suggest that skeletal morphology and muscle morphology contribute independently to biomechanical diversity among closely related species, indicating the importance of considering both skeletal and muscular variation in studies of ecomorphological diversification.
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http://dx.doi.org/10.1016/j.zool.2018.06.006DOI Listing
August 2018

Dynamic Musculoskeletal Functional Morphology: Integrating diceCT and XROMM.

Anat Rec (Hoboken) 2018 02;301(2):378-406

Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois 60637.

The tradeoff between force and velocity in skeletal muscle is a fundamental constraint on vertebrate musculoskeletal design (form:function relationships). Understanding how and why different lineages address this biomechanical problem is an important goal of vertebrate musculoskeletal functional morphology. Our ability to answer questions about the different solutions to this tradeoff has been significantly improved by recent advances in techniques for quantifying musculoskeletal morphology and movement. Herein, we have three objectives: (1) review the morphological and physiological parameters that affect muscle function and how these parameters interact; (2) discuss the necessity of integrating morphological and physiological lines of evidence to understand muscle function and the new, high resolution imaging technologies that do so; and (3) present a method that integrates high spatiotemporal resolution motion capture (XROMM, including its corollary fluoromicrometry), high resolution soft tissue imaging (diceCT), and electromyography to study musculoskeletal dynamics in vivo. The method is demonstrated using a case study of in vivo primate hyolingual biomechanics during chewing and swallowing. A sensitivity analysis demonstrates that small deviations in reconstructed hyoid muscle attachment site location introduce an average error of 13.2% to in vivo muscle kinematics. The observed hyoid and muscle kinematics suggest that hyoid elevation is produced by multiple muscles and that fascicle rotation and tendon strain decouple fascicle strain from hyoid movement and whole muscle length. Lastly, we highlight current limitations of these techniques, some of which will likely soon be overcome through methodological improvements, and some of which are inherent. Anat Rec, 301:378-406, 2018. © 2018 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ar.23714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786282PMC
February 2018

Determinants of aponeurosis shape change during muscle contraction.

J Biomech 2016 06 26;49(9):1812-1817. Epub 2016 Apr 26.

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.

Aponeuroses are sheet-like elastic tendon structures that cover a portion of the muscle belly and act as insertion sites for muscle fibers while free tendons connect muscles to bones. During shortening contractions, free tendons are loaded in tension and lengthen due to the force acting longitudinally along the muscle׳s line of action. In contrast, aponeuroses increase in length and width, suggesting that aponeuroses are loaded in directions along and orthogonal to the muscle׳s line of action. Because muscle fibers are isovolumetric, they must expand radially as they shorten, potentially generating a force that increases aponeurosis width. We hypothesized that increases in aponeurosis width result from radial expansion of shortening muscle fibers. We tested this hypothesis by combining in situ muscle-tendon measurements with high-speed biplanar fluoroscopy measurements of the turkey׳s lateral gastrocnemius (n=6) at varying levels of isotonic muscle contractions. The change in aponeurosis width during periods of constant force depended on both the amount of muscle shortening and the magnitude of force production. At low to intermediate forces, aponeurosis width increased in direct proportion to fiber shortening. At high forces, aponeurosis width increased to a lesser extent or in some cases, decreased slightly during fiber shortening. Our results demonstrate that forces generated from radial expansion of shortening muscle fibers tend to drive increases in aponeurosis width, whereas longitudinal forces tend to decrease aponeurosis width. Ultimately, it is these two opposing forces that drive changes in aponeurosis width and alter series elastic stiffness during a muscle contraction.
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http://dx.doi.org/10.1016/j.jbiomech.2016.04.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4885790PMC
June 2016

Functional morphology of durophagy in black carp, Mylopharyngodon piceus.

J Morphol 2015 Dec 20;276(12):1422-32. Epub 2015 Aug 20.

Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island.

The black carp, Mylopharyngodon piceus (Osteichthyes: Cyprinidae), crushes its snail and other molluscan prey with robust pharyngeal jaws and strong bite forces. Using gross morphology, histological sectioning, and X-ray reconstruction of moving morphology (XROMM), we investigated structural, behavioral, and mechanical aspects of pharyngeal jaw function in black carp. Strut-like trabeculae in their pharyngeal jaws support large, molariform teeth. The teeth occlude with a hypertrophied basioccipital process that is also reinforced with stout trabeculae. A keratinous chewing pad is firmly connected to the basioccipital process by a series of small bony projections from the base of the pedestal. The pharyngeal jaws have no bony articulations with the skull, and their position is controlled by five paired muscles and one unpaired median muscle. Black carp can crush large molluscs, so we used XROMM to compare pharyngeal jaw postures as fish crushed ceramic tubes of increasing sizes. We found that black carp increase pharyngeal jaw gape primarily by ventral translation of the jaws, with ventral rotation and lateral flaring of the jaws also increasing the space available to accommodate large prey items. A stout, robust ligament connects left and right jaws together firmly, but allows some rotation of the jaws relative to each other. Contrasting with the pharyngeal jaw mechanism of durophagous perciforms with fused left and right lower pharyngeal jaws, we hypothesize that this ligamentous connection may serve to decouple tensile and compressive forces, with the tensile forces borne by the ligament and the compressive forces transferred to the prey.
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http://dx.doi.org/10.1002/jmor.20430DOI Listing
December 2015

Convergence in morphology and masticatory function between the pharyngeal jaws of grass carp, Ctenopharyngodon idella, and oral jaws of amniote herbivores.

J Exp Biol 2014 Jun 27;217(Pt 11):1925-32. Epub 2014 Feb 27.

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.

The cellulose-rich walls that protect plant cells are difficult to digest, and therefore mechanical food processing is a key aspect of herbivory across vertebrates. Cell walls are typically broken down by translation of flattened teeth in the occlusal plane (i.e. grinding) as part of a complex, rhythmic chewing stroke. The grass carp, Ctenopharyngodon idella, is a voracious, invasive herbivorous fish that relies solely on its pharyngeal teeth, located in the back of the throat, for mechanical processing of plant material. Here, we describe the musculoskeletal anatomy of the pharyngeal jaws of grass carp and use XROMM to quantify chewing kinematics and muscle strain. The pharyngeal jaws are suspended in a sling of 11 muscles and maintain no bony articulation with any other skeletal elements in the head. The jaws bear long, serrated teeth that are worn during use into flattened tooth cusps. Our kinematic data show that this wear is the result of the teeth being elevated into occlusion against the basioccipital process and keratinous chewing pad, not tooth-on-tooth occlusion. Pharyngeal jaw elevation results from large strains in the jaw elevator muscle, the levator arcus branchialis V, to drive a pulley-like mechanism that rotates the jaws about a pivot point at the symphysis between the left and right pharyngeal jaws. These complex, rhythmic jaw rotations translate the teeth laterally across the chewing surface throughout the occlusion phase. The grass carp chewing system is strikingly similar in gross morphology and masticatory function to herbivorous chewing strategies in other vertebrates.
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http://dx.doi.org/10.1242/jeb.096248DOI Listing
June 2014

Bite force is limited by the force-length relationship of skeletal muscle in black carp, Mylopharyngodon piceus.

Biol Lett 2013 Apr 13;9(2):20121181. Epub 2013 Feb 13.

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA.

Bite force is critical to feeding success, especially in animals that crush strong, brittle foods. Maximum bite force is typically measured as one value per individual, but the force-length relationship of skeletal muscle suggests that each individual should possess a range of gape height-specific, and, therefore, prey size-specific, bite forces. We characterized the influence of prey size on pharyngeal jaw bite force in the snail-eating black carp (Mylopharyngodon piceus, family Cyprinidae), using feeding trials on artificial prey that varied independently in size and strength. We then measured jaw-closing muscle lengths in vivo for each prey size, and then determined the force-length relationship of the same muscle in situ using tetanic stimulations. Maximum bite force was surprisingly high: the largest individual produced nearly 700 N at optimal muscle length. Bite force decreased on large and small prey, which elicited long and short muscle lengths, respectively, demonstrating that the force-length relationship of skeletal muscle results in prey size-specific bite force.
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http://dx.doi.org/10.1098/rsbl.2012.1181DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3639770PMC
April 2013

Flexibility in starting posture drives flexibility in kinematic behavior of the kinethmoid-mediated premaxillary protrusion mechanism in a cyprinid fish, Cyprinus carpio.

J Exp Biol 2012 Jul;215(Pt 13):2262-72

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.

Premaxillary protrusion in cypriniform fishes involves rotation of the kinethmoid, an unpaired skeletal element in the dorsal midline of the rostrum. No muscles insert directly onto the kinethmoid, so its rotation must be caused by the movement of other bones. In turn, the kinethmoid is thought to push on the ascending processes of the premaxillae, effecting protrusion. To determine the causes and effects of kinethmoid motion, we used XROMM (x-ray reconstruction of moving morphology) to measure the kinematics of cranial bones in common carp, Cyprinus carpio. Mean kinethmoid rotation was 83 deg during premaxillary protrusion (18 events in 3 individuals). The kinethmoid rotates in a coordinated way with ventral translation of the maxillary bridge, and this ventral translation is likely driven primarily by the A1β muscle. Analyses of flexibility (variability between behaviors) and coordination (correlation between bones within a behavior) indicate that motion of the maxillary bridge, not the lower jaw, drives premaxillary protrusion. Thus, upper jaw protrusion is decoupled from lower jaw depression, allowing for two separate modes of protrusion, open mouth and closed mouth. These behaviors serve different functions: to procure food and to sort food, respectively. Variation in starting posture of the maxilla alone dictates which type of protrusion is performed; downstream motions are invariant. For closed mouth protrusion, a ventrally displaced maxillary starting posture causes kinethmoid rotation to produce more ventrally directed premaxillary protrusion. This flexibility, bestowed by the kinethmoid-maxillary bridge-A1β mechanism, one of several evolutionary novelties in the cypriniform feeding mechanism, may have contributed to the impressive trophic diversity that characterizes this speciose lineage.
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http://dx.doi.org/10.1242/jeb.070516DOI Listing
July 2012

Locomotory transition from water to sand and its effects on undulatory kinematics in sand lances (Ammodytidae).

J Exp Biol 2011 Feb;214(Pt 4):657-64

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.

Sand lances, fishes in the genus Ammodytes, exhibit a peculiar burrowing behavior in which they appear to swim rapidly into the substrate. They use posteriorly propagated undulations of the body to move in both water, a Newtonian fluid, and in sand, a non-Newtonian, granular substrate. In typical aquatic limbless locomotion, undulations of the body push against water, which flows because it is incapable of supporting the static stresses exerted by the animal, thus the undulations move in world space (slipping wave locomotion). In typical terrestrial limbless locomotion, these undulations push against substrate irregularities and move relatively little in world space (non-slipping wave locomotion). We used standard and X-ray video to determine the roles of slipping wave and non-slipping wave locomotion during burrowing in sand lances. We find that sand lances in water use slipping wave locomotion, similar to most aquatic undulators, but switch to non-slipping waves once they burrow. We identify a progression of three stages in the burrowing process: first, aquatic undulations similar to typical anguilliform locomotion (but without head yaw) push the head into the sand; second, more pronounced undulations of the aquatic portion of the body push most of the animal below ground; third, the remaining above-ground portion of the body ceases undulation and the subterranean portion takes over, transitioning to non-slipping wave locomotion. We find no evidence that sand lances use their body motions to fluidize the sand. Instead, as soon as enough of the body is underground, they undergo a kinematic shift and locomote like terrestrial limbless vertebrates.
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http://dx.doi.org/10.1242/jeb.047068DOI Listing
February 2011

Localization of magnetic pills.

Proc Natl Acad Sci U S A 2011 Feb 21;108(6):2252-7. Epub 2011 Jan 21.

Department of Molecular Pharmacology, Brown University, Providence, RI 02912, USA.

Numerous therapeutics demonstrate optimal absorption or activity at specific sites in the gastrointestinal (GI) tract. Yet, safe, effective pill retention within a desired region of the GI remains an elusive goal. We report a safe, effective method for localizing magnetic pills. To ensure safety and efficacy, we monitor and regulate attractive forces between a magnetic pill and an external magnet, while visualizing internal dose motion in real time using biplanar videofluoroscopy. Real-time monitoring yields direct visual confirmation of localization completely noninvasively, providing a platform for investigating the therapeutic benefits imparted by localized oral delivery of new and existing drugs. Additionally, we report the in vitro measurements and calculations that enabled prediction of successful magnetic localization in the rat small intestines for 12 h. The designed system for predicting and achieving successful magnetic localization can readily be applied to any area of the GI tract within any species, including humans. The described system represents a significant step forward in the ability to localize magnetic pills safely and effectively anywhere within the GI tract. What our magnetic pill localization strategy adds to the state of the art, if used as an oral drug delivery system, is the ability to monitor the force exerted by the pill on the tissue and to locate the magnetic pill within the test subject all in real time. This advance ensures both safety and efficacy of magnetic localization during the potential oral administration of any magnetic pill-based delivery system.
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http://dx.doi.org/10.1073/pnas.1016367108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038721PMC
February 2011