Journal articles on the topic 'Mammals Locomotion'
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BLICKHAN, REINHARD, and ROBERT J. FULL. "Locomotion Energetics of the Ghost Crab: II. Mechanics of the Centre of Mass During Walking and Running." Journal of Experimental Biology 130, no. 1 (July 1, 1987): 155–74. http://dx.doi.org/10.1242/jeb.130.1.155.
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Terrestrial locomotion involving appendages has evolved independently in vertebrates and arthropods. Differences in the mechanical design of the locomotor apparatus could impose constraints on the energetics of locomotion. The mechanical energy fluctuations of the centre of mass of an arthropod, the ghost crab Ocypode quadrata (Fabricius), were examined by integrating the ground reaction forces exerted during sideways locomotion. Crabs used a pendulum-type energy exchange mechanism during walking, analogous to an egg rolling end over end, with the same effectiveness as birds and mammals. Moreover, ghost crabs were found to have two running gaits. A switch from a slow to a fast run occurred at the same speed and stride frequency predicted for the trot-gallop transition of a quadrupedal mammal of the same body mass. In addition, the mass-specific mechanical energy developed over a unit distance was independent of speed and was within the limits measured for birds and mammals. Despite the obvious differences in mechanical design between crabs and mammals, energy-conserving mechanisms and the efficiency of locomotion were remarkably similar. These similarities may result from the fact that the muscles that generate forces during terrestrial locomotion have relatively conservative mechanical and energetic properties.
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Janis, Christine M., and Alberto Martín-Serra. "Postcranial elements of small mammals as indicators of locomotion and habitat." PeerJ 8 (September 2, 2020): e9634. http://dx.doi.org/10.7717/peerj.9634.
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Many studies have shown a correlation between postcranial anatomy and locomotor behavior in mammals, but the postcrania of small mammals (<5 kg) is often considered to be uninformative of their mode of locomotion due to their more generalized overall anatomy. Such small body size was true of all mammals during the Mesozoic. Anatomical correlates of locomotor behavior are easier to determine in larger mammals, but useful information can be obtained from the smaller ones. Limb bone proportions (e.g., brachial index) can be useful locomotor indicators; but complete skeletons, or even complete long bones, are rare for Mesozoic mammals, although isolated articular surfaces are often preserved. Here we examine the correlation of the morphology of long bone joint anatomy (specifically articular surfaces) and locomotor behavior in extant small mammals and demonstrate that such anatomy may be useful for determining the locomotor mode of Mesozoic mammals, at least for the therian mammals.
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Grant, Robyn A., Vicki Breakell, and Tony J. Prescott. "Whisker touch sensing guides locomotion in small, quadrupedal mammals." Proceedings of the Royal Society B: Biological Sciences 285, no. 1880 (June 13, 2018): 20180592. http://dx.doi.org/10.1098/rspb.2018.0592.
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All small mammals have prominent facial whiskers that they employ as tactile sensors to guide navigation and foraging in complex habitats. Nocturnal, arboreal mammals tend to have the longest and most densely packed whiskers, and semi-aquatic mammals have the most sensitive. Here we present evidence to indicate that many small mammals use their whiskers to tactually guide safe foot positioning. Specifically, in 11, small, non-flying mammal species, we demonstrate that forepaw placement always falls within the ground contact zone of the whisker field and that forepaw width is always smaller than whisker span. We also demonstrate commonalities of whisker scanning movements (whisking) and elements of active control, associated with increasing contact with objects of interest, across multiple small mammal species that have previously only been shown in common laboratory animals. Overall, we propose that guiding locomotion, alongside environment exploration, is a common function of whisker touch sensing in small, quadrupedal mammals.
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Williams, Terrie M. "The evolution of cost efficient swimming in marine mammals: limits to energetic optimization." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 354, no. 1380 (January 29, 1999): 193–201. http://dx.doi.org/10.1098/rstb.1999.0371.
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Mammals re–entered the oceans less than 60 million years ago. The transition from a terrestrial to an aquatic lifestyle required extreme morphological and behavioural modifications concomitant with fundamentally different locomotor mechanisms for moving on land and through water. Energetic transport costs typically reflect such different locomotor modes, but can not be discerned from the fossil record. In this study the energetic challenges associated with changing from terrestrial to aquatic locomotion in primitive marine mammals are examined by comparing the transport, maintenance and locomotor costs of extant mammals varying in degree of aquatic specialization. The results indicate that running and swimming specialists have converged on an energetic optimum for locomotion. An allometric expression, COT TOT = 7.79 mass −0.29 ( r 2 = 0.83, n = 6 species), describes the total cost of transport in J kg −1 m −1 for swimming marine mammals ranging in size from 21 kg to 15,000 kg. This relation is indistinguishable from that describing total transport costs in running mammals. In contrast, the transitional lifestyle of semi–aquatic mammals, similar to that of ancestral marine mammals, incurs costs that are 2.4–5.1 times higher than locomotor specialists. These patterns suggest that primitive marine mammals confronted an energetic hurdle before returning to costs reminiscent of their terrestrial ancestry, and may have reached an evolutionary limit for energetic optimization during swimming.
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Webster, KN, and TJ Dawson. "Is the energetics of mammalian hopping locomotion advantageous in arid environments?" Australian Mammalogy 26, no. 2 (2004): 153. http://dx.doi.org/10.1071/am04153.
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Although hopping is a relatively rare mammalian gait, hopping mammals are common in arid environments. Arid environments are open, with patchy resources, and the widespread use of hopping by arid zone mammals appears to be related to the benefits of fast locomotion. In several species, fast hopping is economical in comparison to fast quadrupedal running. These hopping species can reach greater maximum aerobic speeds than similarly sized runners. Faster locomotion can reduce predation risk and increase opportunities to exploit open microhabitats. More economical locomotion may improve a hopping mammal's ability to adopt alternative foraging strategies. The disadvantages of hopping include an increased cost of slow locomotion, reduced manoeuvrability at slow speeds and reduced ability to exploit densely vegetated patches.
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Ryczko, Dimitri, Jackson J. Cone, Michael H. Alpert, Laurent Goetz, François Auclair, Catherine Dubé, Martin Parent, Mitchell F. Roitman, Simon Alford, and Réjean Dubuc. "A descending dopamine pathway conserved from basal vertebrates to mammals." Proceedings of the National Academy of Sciences 113, no. 17 (April 11, 2016): E2440—E2449. http://dx.doi.org/10.1073/pnas.1600684113.
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Dopamine neurons are classically known to modulate locomotion indirectly through ascending projections to the basal ganglia that project down to brainstem locomotor networks. Their loss in Parkinson’s disease is devastating. In lampreys, we recently showed that brainstem networks also receive direct descending dopaminergic inputs that potentiate locomotor output. Here, we provide evidence that this descending dopaminergic pathway is conserved to higher vertebrates, including mammals. In salamanders, dopamine neurons projecting to the striatum or brainstem locomotor networks were partly intermingled. Stimulation of the dopaminergic region evoked dopamine release in brainstem locomotor networks and concurrent reticulospinal activity. In rats, some dopamine neurons projecting to the striatum also innervated the pedunculopontine nucleus, a known locomotor center, and stimulation of the dopaminergic region evoked pedunculopontine dopamine release in vivo. Finally, we found dopaminergic fibers in the human pedunculopontine nucleus. The conservation of a descending dopaminergic pathway across vertebrates warrants re-evaluating dopamine’s role in locomotion.
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JORDAN, LARRY M. "Initiation of Locomotion in Mammals." Annals of the New York Academy of Sciences 860, no. 1 NEURONAL MECH (November 1998): 83–93. http://dx.doi.org/10.1111/j.1749-6632.1998.tb09040.x.
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Giuliodori, Mauricio J., Heidi L. Lujan, Whitney S. Briggs, and Stephen E. DiCarlo. "A model of locomotor-respiratory coupling in quadrupeds." Advances in Physiology Education 33, no. 4 (December 2009): 315–18. http://dx.doi.org/10.1152/advan.00057.2009.
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Locomotion and respiration are not independent phenomena in running mammals because locomotion and respiration both rely on cyclic movements of the ribs, sternum, and associated musculature. Thus, constraints are imposed on locomotor and respiratory function by virtue of their linkage. Specifically, locomotion imposes mechanical constraints on breathing that require the respiratory cycle to be synchronized with gait. Thus, many mammals, including humans, synchronize respiration with the movement of the limbs during locomotion. For example, quadrupeds synchronize locomotor and respiratory cycles at a 1:1 ratio (stride/breath) over a wide range of speeds. Interestingly, quadrupeds maintain an almost constant stride frequency (and therefore respiratory frequency) at different speeds. To increase speed, quadrupeds lengthen their stride. Accordingly, to increase minute ventilation, quadrupeds must increase tidal volume since respiratory rate is coupled with stride frequency. We developed a simple, inexpensive, and easy to build model to demonstrate this concept. A model was chosen because models significantly enhance student understanding. Students are drawn into discussion by the power of learning that is associated with manipulating and thinking about objects. Building and using this model strengthen the concept that locomotor-respiratory coupling provides a basis for the appropriate matching of lung ventilation to running speed and metabolic power.
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Rossignol, S., G. Barrière, O. Alluin, and A. Frigon. "Re-expression of Locomotor Function After Partial Spinal Cord Injury." Physiology 24, no. 2 (April 2009): 127–39. http://dx.doi.org/10.1152/physiol.00042.2008.
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After a complete spinal section, quadruped mammals (cats, rats, and mice) can generally regain hindlimb locomotion on a treadmill because the spinal cord below the lesion can express locomotion through a neural circuitry termed the central pattern generator (CPG). In this review, we propose that the spinal CPG also plays a crucial role in the locomotor recovery after incomplete spinal cord injury.
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Fish, F. E., and R. V. Baudinette. "Energetics of locomotion by the Australian water rat (Hydromys chrysogaster): a comparison of swimming and running in a semi-aquatic mammal." Journal of Experimental Biology 202, no. 4 (February 15, 1999): 353–63. http://dx.doi.org/10.1242/jeb.202.4.353.
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Semi-aquatic mammals occupy a precarious evolutionary position, having to function in both aquatic and terrestrial environments without specializing in locomotor performance in either environment. To examine possible energetic constraints on semi-aquatic mammals, we compared rates of oxygen consumption for the Australian water rat (Hydromys chrysogaster) using different locomotor behaviors: swimming and running. Aquatic locomotion was investigated as animals swam in a water flume at several speeds, whereas water rats were run on a treadmill to measure metabolic effort during terrestrial locomotion. Water rats swam at the surface using alternate pelvic paddling and locomoted on the treadmill using gaits that included walk, trot and half-bound. Water rats were able to run at twice their maximum swimming velocity. Swimming metabolic rate increased with velocity in a pattern similar to the ‘humps’ and ‘hollows’ for wave drag experienced by bodies moving at the water surface. Metabolic rate increased linearly during running. Over equivalent velocities, the metabolic rate for running was 13–40 % greater than for swimming. The minimum cost of transport for swimming (2.61 J N-1 m-1) was equivalent to values for other semi-aquatic mammals. The lowest cost for running (2.08 J N-1 m-1) was 20 % lower than for swimming. When compared with specialists at the extremes of the terrestrial-aquatic continuum, the energetic costs of locomoting either in water or on land were high for the semi-aquatic Hydromys chrysogaster. However, the relative costs for H. chrysogaster were lower than when an aquatic specialist attempts to move on land or a terrestrial specialist attempts to swim.
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Gerasimenko, Yury, Chet Preston, Hui Zhong, Roland R. Roy, V. Reggie Edgerton, and Prithvi K. Shah. "Rostral lumbar segments are the key controllers of hindlimb locomotor rhythmicity in the adult spinal rat." Journal of Neurophysiology 122, no. 2 (August 1, 2019): 585–600. http://dx.doi.org/10.1152/jn.00810.2018.
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The precise location and functional organization of the spinal neuronal locomotor-related networks in adult mammals remain unclear. Our recent neurophysiological findings provided empirical evidence that the rostral lumbar spinal cord segments play a critical role in the initiation and generation of the rhythmic activation patterns necessary for hindlimb locomotion in adult spinal rats. Since added epidural stimulation at the S1 segments significantly enhanced the motor output generated by L2 stimulation, these data also suggested that the sacral spinal cord provides a strong facilitory influence in rhythm initiation and generation. However, whether L2 will initiate hindlimb locomotion in the absence of S1 segments, and whether S1 segments can facilitate locomotion in the absence of L2 segments remain unknown. Herein, adult rats received complete spinal cord transections at T8 and then at either L2 or S1. Rats with spinal cord transections at T8 and S1 remained capable of generating coordinated hindlimb locomotion when receiving epidural stimulation at L2 and when ensembles of locomotor related loadbearing input were present. In contrast, minimal locomotion was observed when S1 stimulation was delivered after spinal cord transections at T8 and L2. Results were similar when the nonspecific serotonergic agonists were administered. These results demonstrate in adult rats that rostral lumbar segments are essential for the regulation of hindlimb locomotor rhythmicity. In addition, the more caudal spinal networks alone cannot control locomotion in the absence of the rostral segments around L2 even when loadbearing rhythmic proprioceptive afferent input is imposed. NEW & NOTEWORTHY The exact location of the spinal neuronal locomotor-related networks in adult mammals remains unknown. The present data demonstrate that when the rostral lumbar spinal segments (~L2) are completely eliminated in thoracic spinal adult rats, hindlimb stepping is not possible with neurochemical modulation of the lumbosacral cord. In contrast, eliminating the sacral cord retains stepping ability. These observations highlight the importance of rostral lumbar segments in generating effective mammalian locomotion.
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Park, Sung Ho, and Dong Pyo Hong. "Optimal Locomotive Parameters of Four-Legged Bio-Robot by Minimizing Energy Consumption." Advanced Materials Research 945-949 (June 2014): 1435–41. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.1435.
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Four-Legged walking robot is mechanically modeled by copying mammals, which have 13 links and 12 joints. But mechanical models are more on technical rather than on biological concepts, which yield unstable locomotion with low speed. Advanced biological locomotive phenomena and their structural characteristics are applied to the mechanical model and simulated for the one cycle. Torques at joints are calculated and finally converted to total consumed energy. Variables, specifying structure and locomotion, are applied to the simulation as a time function, and the optimal variables which minimize energy expenditure are derived which can be directly applied to the Quadruped locomotion.
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Konow, Nicolai, Jorn A. Cheney, Thomas J. Roberts, J. Rhea S. Waldman, and Sharon M. Swartz. "Spring or string: does tendon elastic action influence wing muscle mechanics in bat flight?" Proceedings of the Royal Society B: Biological Sciences 282, no. 1816 (October 7, 2015): 20151832. http://dx.doi.org/10.1098/rspb.2015.1832.
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Tendon springs influence locomotor movements in many terrestrial animals, but their roles in locomotion through fluids as well as in small-bodied mammals are less clear. We measured muscle, tendon and joint mechanics in an elbow extensor of a small fruit bat during ascending flight. At the end of downstroke, the tendon was stretched by elbow flexion as the wing was folded. At the end of upstroke, elastic energy was recovered via tendon recoil and extended the elbow, contributing to unfurling the wing for downstroke. Compared with a hypothetical ‘string-like’ system lacking series elastic compliance, the tendon spring conferred a 22.5% decrease in muscle fascicle strain magnitude. Our findings demonstrate tendon elastic action in a small flying mammal and expand our understanding of the occurrence and action of series elastic actuator mechanisms in fluid-based locomotion.
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Jones, Billie, Alberto Martín-Serra, Emily J. Rayfield, and Christine M. Janis. "Distal Humeral Morphology Indicates Locomotory Divergence in Extinct Giant Kangaroos." Journal of Mammalian Evolution 29, no. 1 (November 9, 2021): 27–41. http://dx.doi.org/10.1007/s10914-021-09576-3.
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AbstractPrevious studies of the morphology of the humerus in kangaroos showed that the shape of the proximal humerus could distinguish between arboreal and terrestrial taxa among living mammals, and that the extinct “giant” kangaroos (members of the extinct subfamily Sthenurinae and the extinct macropodine genus Protemnodon) had divergent humeral anatomies from extant kangaroos. Here, we use 2D geometric morphometrics to capture the shape of the distal humerus in a range of extant and extinct marsupials and obtain similar results: sthenurines have humeral morphologies more similar to arboreal mammals, while large Protemnodon species (P. brehus and P. anak) have humeral morphologies more similar to terrestrial quadrupedal mammals. Our results provide further evidence for prior hypotheses: that sthenurines did not employ a locomotor mode that involved loading the forelimbs (likely employing bipedal striding as an alternative to quadrupedal or pentapedal locomotion at slow gaits), and that large Protemnodon species were more reliant on quadrupedal locomotion than their extant relatives. This greater diversity of locomotor modes among large Pleistocene kangaroos echoes studies that show a greater diversity in other aspects of ecology, such as diet and habitat occupancy.
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Seebacher, Frank, Peter G. Elsworth, and Craig E. Franklin. "Ontogenetic changes of swimming kinematics in a semi-aquatic reptile (Crocodylus porosus)." Australian Journal of Zoology 51, no. 1 (2003): 15. http://dx.doi.org/10.1071/zo02036.
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Semi-aquatic animals represent a transitional locomotor condition characterised by the possession of morphological features that allow locomotion both in water and on land. Most ecologically important behaviours of crocodilians occur in the water, raising the question of whether their 'terrestrial construction' constrains aquatic locomotion. Moreover, the demands for aquatic locomotion change with life-history stage. It was the aim of this research to determine the kinematic characteristics and efficiency of aquatic locomotion in different-sized crocodiles (Crocodylus porosus). Aquatic propulsion was achieved primarily by tail undulations, and the use of limbs during swimming was observed only in very small animals or at low swimming velocities in larger animals. Over the range of swimming speeds we examined, tail beat amplitude did not change with increasing velocity, but amplitude increased significantly with body length. However, amplitude expressed relative to body length decreased with increasing body length. Tail beat frequency increased with swimming velocity but there were no differences in frequency between different-sized animals. Mechanical power generated during swimming and thrust increased non-linearly with swimming velocity, but disproportionally so that kinematic efficiency decreased with increasing swimming velocity. The importance of unsteady forces, expressed as the reduced frequency, increased with increasing swimming velocity. Amplitude is the main determinant of body-size-related increases in swimming velocity but, compared with aquatic mammals and fish, crocodiles are slow swimmers probably because of constraints imposed by muscle performance and unsteady forces opposing forward movement. Nonetheless, the kinematic efficiency of aquatic locomotion in crocodiles is comparable to that of fully aquatic mammals, and it is considerably greater than that of semi-aquatic mammals.
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Blob, R. W., and A. A. Biewener. "In vivo locomotor strain in the hindlimb bones of alligator mississippiensis and iguana iguana: implications for the evolution of limb bone safety factor and non-sprawling limb posture." Journal of Experimental Biology 202, no. 9 (May 1, 1999): 1023–46. http://dx.doi.org/10.1242/jeb.202.9.1023.
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Limb postures of terrestrial tetrapods span a continuum from sprawling to fully upright; however, most experimental investigations of locomotor mechanics have focused on mammals and ground-dwelling birds that employ parasagittal limb kinematics, leaving much of the diversity of tetrapod locomotor mechanics unexplored. This study reports measurements of in vivo locomotor strain from the limb bones of lizard (Iguana iguana) and crocodilian (Alligator mississippiensis) species, animals from previously unsampled phylogenetic lineages with non-parasagittal limb posture and kinematics. Principal strain orientations and shear strain magnitudes indicate that the limb bones of these species experience considerable torsion during locomotion. This contrasts with patterns commonly observed in mammals, but matches predictions from kinematic observations of axial rotation in lizard and crocodilian limbs. Comparisons of locomotor load magnitudes with the mechanical properties of limb bones in Alligator and Iguana indicate that limb bone safety factors in bending for these species range from 5.5 to 10.8, as much as twice as high as safety factors previously calculated for mammals and birds. Limb bone safety factors in shear (3.9-5.4) for Alligator and Iguana are also moderately higher than safety factors to yield in bending for birds and mammals. Finally, correlations between limb posture and strain magnitudes in Alligator show that at some recording locations limb bone strains can increase during upright locomotion, in contrast to expectations based on size-correlated changes in posture among mammals that limb bone strains should decrease with the use of an upright posture. These data suggest that, in some lineages, strain magnitudes may not have been maintained at constant levels through the evolution of a non-sprawling posture unless the postural change was accompanied by a shift to parasagittal kinematics or by an evolutionary decrease in body size.
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Bullimore, Sharon R., and Jeremy F. Burn. "Scaling of elastic energy storage in mammalian limb tendons: do small mammals really lose out?" Biology Letters 1, no. 1 (March 22, 2005): 57–59. http://dx.doi.org/10.1098/rsbl.2004.0243.
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It is widely believed that elastic energy storage is more important in the locomotion of larger mammals. This is based on: (a) comparison of kangaroos with the smaller kangaroo rat; and (b) calculations that predict that the capacity for elastic energy storage relative to body mass increases with size. Here we argue that: (i) data from kangaroos and kangaroo rats cannot be generalized to other mammals; (ii) the elastic energy storage capacity relative to body mass is not indicative of the importance of elastic energy to an animal; and (iii) the contribution of elastic energy to the mechanical work of locomotion will not increase as rapidly with size as the mass-specific energy storage capacity, because larger mammals must do relatively more mechanical work per stride. We predict how the ratio of elastic energy storage to mechanical work will change with size in quadrupedal mammals by combining empirical scaling relationships from the literature. The results suggest that the percentage contribution of elastic energy to the mechanical work of locomotion decreases with size, so that elastic energy is more important in the locomotion of smaller mammals. This now needs to be tested experimentally.
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Rossignol, Serge. "Plasticity of connections underlying locomotor recovery after central and/or peripheral lesions in the adult mammals." Philosophical Transactions of the Royal Society B: Biological Sciences 361, no. 1473 (August 4, 2006): 1647–71. http://dx.doi.org/10.1098/rstb.2006.1889.
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This review discusses some aspects of plasticity of connections after spinal injury in adult animal models as a basis for functional recovery of locomotion. After reviewing some pitfalls that must be avoided when claiming functional recovery and the importance of a conceptual framework for the control of locomotion, locomotor recovery after spinal lesions, mainly in cats, is summarized. It is concluded that recovery is partly due to plastic changes within the existing spinal locomotor networks. Locomotor training appears to change the excitability of simple reflex pathways as well as more complex circuitry. The spinal cord possesses an intrinsic capacity to adapt to lesions of central tracts or peripheral nerves but, as a rule, adaptation to lesions entails changes at both spinal and supraspinal levels. A brief summary of the spinal capacity of the rat, mouse and human to express spinal locomotor patterns is given, indicating that the concepts derived mainly from work in the cat extend to other adult mammals. It is hoped that some of the issues presented will help to evaluate how plasticity of existing connections may combine with and potentiate treatments designed to promote regeneration to optimize remaining motor functions.
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Studholme, Keith M., Heinrich S. Gompf, and Lawrence P. Morin. "Brief light stimulation during the mouse nocturnal activity phase simultaneously induces a decline in core temperature and locomotor activity followed by EEG-determined sleep." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 304, no. 6 (March 15, 2013): R459—R471. http://dx.doi.org/10.1152/ajpregu.00460.2012.
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Light exerts a variety of effects on mammals. Unexpectedly, one of these effects is the cessation of nocturnal locomotion and the induction of behavioral sleep (photosomnolence). Here, we extend the initial observations in several ways, including the fundamental demonstration that core body temperature (Tc) drops substantially (about 1.5°C) in response to the light stimulation at CT15 or CT18 in a manner suggesting that the change is a direct response to light rather than simply a result of the locomotor suppression. The results show that 1) the decline of locomotion and Tc begin soon after nocturnal light stimulation; 2) the variability in the magnitude and onset of light-induced locomotor suppression is very large, whereas the variability in Tc is very small; 3) Tc recovers from the light-induced decline in advance of the recovery of locomotion; 4) under entrained and freerunning conditions, the daily late afternoon Tc increase occurs in advance of the corresponding increase in wheel running; and 5) toward the end of the subjective night, the nocturnally elevated Tc persists longer than does locomotor activity. Finally, EEG measurements confirm light-induced sleep and, when Tc or locomotion was measured, show their temporal association with sleep onset. Both EEG- and immobility-based sleep detection methods confirm rapid induction of light-induced sleep. The similarities between light-induced loss of locomotion and drop in Tc suggest a common cause for parallel responses. The photosomnolence response may be contingent upon both the absence of locomotion and a simultaneous low Tc.
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Preuschoft, Holger, and Jens Lorenz Franzen. "Locomotion and biomechanics in Eocene mammals from Messel." Palaeobiodiversity and Palaeoenvironments 92, no. 4 (October 3, 2012): 459–76. http://dx.doi.org/10.1007/s12549-012-0103-7.
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Behrman, Andrea L., and Susan J. Harkema. "Locomotor Training After Human Spinal Cord Injury: A Series of Case Studies." Physical Therapy 80, no. 7 (July 1, 2000): 688–700. http://dx.doi.org/10.1093/ptj/80.7.688.
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AbstractMany individuals with spinal cord injury (SCI) do not regain their ability to walk, even though it is a primary goal of rehabilitation. Mammals with thoracic spinal cord transection can relearn to step with their hind limbs on a treadmill when trained with sensory input associated with stepping. If humans have similar neural mechanisms for locomotion, then providing comparable training may promote locomotor recovery after SCI. We used locomotor training designed to provide sensory information associated with locomotion to improve stepping and walking in adults after SCI. Four adults with SCIs, with a mean postinjury time of 6 months, received locomotor training. Based on the American Spinal Injury Association (ASIA) Impairment Scale and neurological classification standards, subject 1 had a T5 injury classified as ASIA A, subject 2 had a T5 injury classified as ASIA C, subject 3 had a C6 injury classified as ASIA D, and subject 4 had a T9 injury classified as ASIA D. All subjects improved their stepping on a treadmill. One subject achieved overground walking, and 2 subjects improved their overground walking. Locomotor training using the response of the human spinal cord to sensory information related to locomotion may improve the potential recovery of walking after SCI.
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Janis, Christine M., James G. Napoli, Coral Billingham, and Alberto Martín-Serra. "Proximal Humerus Morphology Indicates Divergent Patterns of Locomotion in Extinct Giant Kangaroos." Journal of Mammalian Evolution 27, no. 4 (January 16, 2020): 627–47. http://dx.doi.org/10.1007/s10914-019-09494-5.
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Abstract Sthenurine kangaroos, extinct “giant kangaroos” known predominantly from the Plio-Pleistocene, have been proposed to have used bipedal striding as a mode of locomotion, based on the morphology of their hind limbs. However, sthenurine forelimb morphology has not been considered in this context, and has important bearing as to whether these kangaroos employed quadrupedal or pentapedal locomotion as a slow gait, as in extant kangaroos. Study of the correlation of morphology of the proximal humerus in a broad range of therian mammals shows that humeral morphology is indicative of the degree of weight-bearing on the forelimbs during locomotion, with terrestrial species being distinctly different from arboreal ones. Extant kangaroos have a proximal humeral morphology similar to extant scansorial (semi-arboreal) mammals, but sthenurine humeri resemble those of suspensory arboreal taxa, which rarely bear weight on their forelimbs, supporting the hypothesis that they used bipedal striding rather than quadrupedal locomotion at slow gaits. The humeral morphology of the enigmatic extinct “giant wallaby,” Protemnodon, may be indicative of a greater extent of quadrupedal locomotion than in extant kangaroos.
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Baudinette, R. V. "The energetics and cardiorespiratory correlates of mammalian terrestrial locomotion." Journal of Experimental Biology 160, no. 1 (October 1, 1991): 209–31. http://dx.doi.org/10.1242/jeb.160.1.209.
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Energy costs of locomotion in mammals can be predicted from running speed and body mass, with the minimum cost decreasing regularly with increasing mass (Mb-0.30). The predictive value of this model is surprising, given the differences in gait and limb structure among mammals. The decrease in mass-specific cost cannot be explained by the work done in moving the limbs and the centre of mass, as animals of different sizes do the same amount of work to move a unit mass a unit distance. The magnitude of the muscle forces involved and the shortening velocity are more likely causes. Terrestrial mammals use a variety of gaits to minimise locomotory energy costs with a ‘preferred speed’ within each of those gaits correlating with the point of greatest economy. The maximum mass-specific energy cost during locomotion is about 10 times the resting level, but there is marked variation among species, especially between wild and domestic forms. The total cost for locomotion in mammals lies between 1 and 6% of the daily energy budget. Hopping is an energetically cheap way of moving in large animals and correlates with phase-locking of respiratory and limb frequencies. This form of coupling is also seen in most other mammals, especially at higher running speeds. Comparison of the relative costs of running, flying and swimming for a given body mass shows a respective decrease, but each of these costs scales similarly with body size.
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Ménard, Ariane, and Sten Grillner. "Diencephalic Locomotor Region in the Lamprey—Afferents and Efferent Control." Journal of Neurophysiology 100, no. 3 (September 2008): 1343–53. http://dx.doi.org/10.1152/jn.01128.2007.
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In vertebrates, locomotion can be initiated by stimulation of the diencephalic locomotor region (DLR). Little is known of the different forebrain regions that provide input to the neurons in DLR. In the lamprey, it had been shown previously that DLR provides monosynaptic input to reticulospinal neurons, which in turn elicit rhythmic ventral root activity at the spinal level. To show that actual locomotor movements are produced from DLR, we use a semi-intact preparation in which the brain stem is exposed and the head fixed, while the body is left to generate actual swimming movements. DLR stimulation induced symmetric locomotor movements with an undulatory wave transmitted along the body. To explore if DLR is under tonic GABAergic input under resting conditions, as in mammals, GABAergic antagonists and agonists were locally administered into DLR. Injections of GABA agonists inhibited locomotion, whereas GABA antagonists facilitated the induction of locomotion. These findings suggest that GABAergic projections provide tonic inhibition that once turned off can release locomotion. Double-labeling experiments were carried out to identify GABAergic projections to the DLR. Populations of GABAergic projection neurons to DLR originated in the caudoventral portion of the medial pallium, the lateral and dorsal pallium, and the striatal area. These different GABAergic projection neurons, which also project to other brain stem motor centers, may represent the basal ganglia output to DLR. Moreover, electrical stimulation of striatum induced long-lasting plateau potentials in reticulospinal cells and associated locomotor episodes dependent on DLR being intact, suggesting that striatum may act via the basal ganglia output identified here.
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Riskin, Daniel K., Corinne J. Kendall, and John W. Hermanson. "The crouching of the shrew: Mechanical consequences of limb posture in small mammals." PeerJ 4 (June 29, 2016): e2131. http://dx.doi.org/10.7717/peerj.2131.
Full textAbstract:
An important trend in the early evolution of mammals was the shift from a sprawling stance, whereby the legs are held in a more abducted position, to a parasagittal one, in which the legs extend more downward. After that transition, many mammals shifted from a crouching stance to a more upright one. It is hypothesized that one consequence of these transitions was a decrease in the total mechanical power required for locomotion, because side-to-side accelerations of the body have become smaller, and thus less costly with changes in limb orientation. To test this hypothesis we compared the kinetics of locomotion in two mammals of body size close to those of early mammals (< 40 g), both with parasagittally oriented limbs: a crouching shrew (Blarina brevicauda; 5 animals, 17 trials) and a more upright vole (Microtus pennsylvanicus; 4 animals, 22 trials). As predicted, voles used less mechanical power per unit body mass to perform steady locomotion than shrews did (P= 0.03). However, while lateral forces were indeed smaller in voles (15.6 ± 2.0% body weight) than in shrews (26.4 ± 10.9%;P= 0.046), the power used to move the body from side-to-side was negligible, making up less than 5% of total power in both shrews and voles. The most power consumed for both species was that used to accelerate the body in the direction of travel, and this was much larger for shrews than for voles (P= 0.01). We conclude that side-to-side accelerations are negligible for small mammals–whether crouching or more upright–compared to their sprawling ancestors, and that a more upright posture further decreases the cost of locomotion compared to crouching by helping to maintain the body’s momentum in the direction of travel.
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Lindstedt, S. L., H. Hoppeler, K. M. Bard, and H. A. Thronson. "Estimate of muscle-shortening rate during locomotion." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 249, no. 6 (December 1, 1985): R699—R703. http://dx.doi.org/10.1152/ajpregu.1985.249.6.r699.
Full textAbstract:
All skeletal muscle can produce roughly the same maximal cross-sectional force; however, the power (energy X time-1) required to develop and maintain that force increases with increasing contraction velocity. Thus the rate of muscle tension development may be of primary importance in setting the energy demand of contracting muscle. We have estimated the rate of muscle shortening during terrestrial locomotion in mammals as a function of body mass. The rate of muscle shortening of the knee extensors is much faster in small than large mammals, scaling in proportion to the -0.23 power of mass. This exponent suggests a constant body size-independent relation among skeletal muscle: O2 consumption, mitochondria content, myosin ATPase activity, and in vivo shortening velocity.
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Pridmore, PA. "Locomotion in Dromiciops-Australis (Marsupialia, Microbiotheriidae)." Australian Journal of Zoology 42, no. 6 (1994): 679. http://dx.doi.org/10.1071/zo9940679.
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Cinematography was used to record locomotion in two adult male Dromiciops australis. Both animals were run on five horizontal dowels varying in diameter from 6.3 to 39 mm and on a horizontal board 89 mm wide. Film records were analysed to determine locomotor velocity, stride length and gait. Locomotor speed and stride length were not affected by substratum, but gait was. Truly symmetrical gaits were used by both animals across a range of speeds on the narrowest dowel. These were characterised by diagnoal couplets of support and a diagonal sequence of limb activition. During locomotion on the other substrata, gaits characterised by slight asymmetry were generally used. The most common of these was one in which diagonal support couplets predominated and each hindlimb was activated slightly ahead of the contralateral forelimb. At higher speeds on the 39-mm dowel the animals sometimes used the half-bound and transverse gallop. The duration of the locomotor cycle decreased exponentially with increasing speed and seemed not to be influenced by substratum diameter, once speed was taken into account. Stride length increased exponentially with speed and also appeared independent of substratum. With symmetrical gaits, the relative phase lag of forelimbs with respect to their ipsilateral hindlimbs changed with speed so that a moderate walkig trot was replaced either by a fast waling trot or fast diagonal sequence walk and ultimately by a slow diagonal sequence run. Two of the symmetrical gaits used by Dromiciops are similar to those used by arboreal didelphids and phalangeroids and by most primates, but are rarely used by other mammals. These gaits appear especially suited to locomotion on narrow branches, suggesting that this species may utilise such substrata to a significant extent in nature. The asymmetrical gaits used by Dromiciops, the half-bound and transverse gallop, are used by various other quadrupedal marsupials, although not commonly by arboreal didelphids. It is conjectured that the symmetrical marsupials, although not commonly by arboreal didelphids and phalangeroids were present in ancestral marsupials and that the latter forms also used the half-bound or transverse gallop. Absolute speed at the transition from symmetrical to asymmetrical gaits ('trot-gallop transition') exceeded that predicted by allometric equations derived from data for terrestrial placental mammals. Relative speed (as measured by the square root of the Froude number) was also higher at this transition than in placentals.
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Fish, F. E., P. B. Frappell, R. V. Baudinette, and P. M. MacFarlane. "Energetics of terrestrial locomotion of the platypus Ornithorhynchus anatinus." Journal of Experimental Biology 204, no. 4 (February 15, 2001): 797–803. http://dx.doi.org/10.1242/jeb.204.4.797.
Full textAbstract:
The platypus Ornithorhynchus anatinus Shaw displays specializations in its limb structure for swimming that could negatively affect its terrestrial locomotion. Platypuses walked on a treadmill at speeds of 0.19-1.08 m × s(−1). Video recordings were used for gait analysis, and the metabolic rate of terrestrial locomotion was studied by measuring oxygen consumption. Platypuses used walking gaits (duty factor >0.50) with a sprawled stance. To limit any potential interference from the extensive webbing on the forefeet, platypuses walk on their knuckles. Metabolic rate increased linearly over a 2.4-fold range with increasing walking speed in a manner similar to that of terrestrial mammals, but was low as a result of the relatively low standard metabolic rate of this monotreme. The dimensionless cost of transport decreased with increasing speed to a minimum of 0.79. Compared with the cost of transport for swimming, the metabolic cost for terrestrial locomotion was 2.1 times greater. This difference suggests that the platypus may pay a price in terrestrial locomotion by being more aquatically adapted than other semi-aquatic or terrestrial mammals.
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Patla, A. E., T. W. Calvert, and R. B. Stein. "Model of a pattern generator for locomotion in mammals." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 248, no. 4 (April 1, 1985): R484—R494. http://dx.doi.org/10.1152/ajpregu.1985.248.4.r484.
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This paper presents an analytic model of a limb pattern generator that can produce complex muscle activation patterns such as those shown to control the limbs of cats. The limb pattern generator is considered to have a tonic input and six outputs; this provides for flexion and extension of representative muscles for each of the three joints of the limb. The pattern generator functions as a community of labile synthesized relaxation oscillators that alters its output in response to input. This model was studied using electromyographic data from an experiment conducted on an acute postmammillary cat preparation. The results suggest that the limb pattern generator can be represented as three subsystems: an oscillator that produces the fundamental frequency of the output in response to the tonic signal, nonlinear shaping functions that mold the oscillator output into the basic complex pattern, and appropriate weighting functions that generate the muscle activity pattern from basic waveforms. The model can account for speed changes in locomotion with a relatively smooth change of system parameters. The pattern generator model is generative, amenable to simulation studies, and can be realized by a neural network.
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Fournier, R. A., and J. M. Weber. "Locomotory energetics and metabolic fuel reserves of the Virginia opossum." Journal of Experimental Biology 197, no. 1 (December 1, 1994): 1–16. http://dx.doi.org/10.1242/jeb.197.1.1.
Full textAbstract:
Marsupials have lower resting metabolic rates than placental mammals, but it is not clear whether particular species can extend this energetic advantage to locomotion. Some active marsupials have a low cost of locomotion, but other more sedentary species, such as the Virginia opossum, appear to run very inefficiently. Steady-state rates of O2 consumption (VO2) and CO2 production (VCO2) were measured at rest and during horizontal treadmill exercise in wild-caught, trained opossums. Average daily VO2 in in undisturbed animals was 7.73 +/- 0.40 ml O2 kg-1 min-1 (5.67 +/- 0.20 ml O2 kg-1 min-1 during light and 9.84 +/- 0.81 ml O2 kg-1 min-1 during dark hours, mean +/- S.E.M., N = 6). Net cost of locomotion ranged between 6.16 and 8.99 J kg-1 s-1 as speed increased and was always higher than for an average mammal of equivalent mass. Net cost of transport decreased as speed increased and was 15-80% higher than for an average mammal. During aerobic locomotion, most of the energy was provided by carbohydrate oxidation, which accounted for 60-95% of VO2 as speed increased. Glycogen and triglyceride reserves were quantified in the major storage depots to estimate potential survival time and travelling distance. Enough metabolic fuel was stored to survive for at least 1 week without eating, and 95% of this energy was in adipose tissue triglycerides. However, maximal travelling distance was less than 2 km because opossum locomotion is mainly supported by carbohydrate reserves, which represented only 4% of the available energy. We conclude that aerobic, ground locomotion of Virginia opossums is associated with two major energetic handicaps because their particularly high cost of transport and the nature of the main oxidative fuel they consume are both incompatible with prolonged locomotion.
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Myers, M. J., and K. Steudel. "Effect of limb mass and its distribution on the energetic cost of running." Journal of Experimental Biology 116, no. 1 (May 1, 1985): 363–73. http://dx.doi.org/10.1242/jeb.116.1.363.
Full textAbstract:
Functional morphologists have traditionally regarded cost of locomotion as an important influence on the design of locomotor structures. If cost of locomotion is an important constraint in the natural selection of these structures, it should be possible to show that animals differing in limb morphology also differ in their locomotor costs. In previous experiments on three species of cursorial mammals differing considerably in limb structure, no such differences were detected. Since the factors that determine the rate of energy consumption of a running animal are not well understood, we felt that the effect of limb morphology on cost could best be examined in a system in which only the inertial properties of limbs were varied while other factors remained constant. Consequently, we have measured changes in the rate of energy consumption of running human subjects produced by artificial alterations in limb inertial properties. Other variables that might influence cost have been controlled. We found that the cost of adding a given mass to the limbs is significantly greater than adding it to the centre of mass and that this effect becomes more pronounced as the limb loads are moved distally. Thus a clear effect of limb mass and its distribution on cost of locomotion has been demonstrated.
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Zavodszky, Anna M., and Gabrielle A. Russo. "Comparative and functional morphology of chevron bones among mammals." Journal of Mammalogy 101, no. 2 (February 18, 2020): 403–16. http://dx.doi.org/10.1093/jmammal/gyaa010.
Full textAbstract:
Abstract Tail morphology and function vary considerably across mammals. While studies of the mammalian tail have paid increasing attention to the caudal vertebrae, the chevron bones, ventrally positioned elements that articulate with the caudal vertebrae of most species and that serve to protect blood vessels and provide attachment sites for tail flexor musculature, have largely been ignored. Here, morphological variation in chevron bones is documented systematically among mammals possessing different tail locomotor functions, including prehensility, terrestrial propulsion (use for pentapedal locomotion), and postural prop, during which chevron bones are presumably under different mechanical stresses or serve different mechanical roles. Several chevron bone morphotypes were identified along the tail, varying both within and between tail regions. While some morphotypes were present across many or all clades surveyed, other morphotypes were clade-specific. Chevron bone dorsoventral height was examined at key vertebral levels among closely related species with different tail locomotor functions to assess whether variation followed any functional patterns. Dorsoventral height of chevron bones differed between prehensile- and nonprehensile-tailed, prop-tailed and nonprop-tailed, and pentapedal and nonpentapedal mammals. However, small sample sizes precluded rigorous statistical analyses. Distinctions were also qualified among species (not grouped by tail locomotor function), and the utility of metrics for quantifying specific aspects of chevron bone anatomy is discussed. This study offers information about the functional morphology of mammalian tails and has implications for reconstructing tail function in the fossil record.
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Deban, Stephen M., and David R. Carrier. "Hypaxial muscle activity during running and breathing in dogs." Journal of Experimental Biology 205, no. 13 (July 1, 2002): 1953–67. http://dx.doi.org/10.1242/jeb.205.13.1953.
Full textAbstract:
SUMMARYThe axial muscles of terrestrial vertebrates serve two potentially conflicting functions, locomotion and lung ventilation. To differentiate the locomotor and ventilatory functions of the hypaxial muscles in mammals, we examined the locomotor and ventilatory activity of the trunk muscles of trotting dogs under two conditions: when the ventilatory cycle and the locomotor cycle were coupled and when they were uncoupled. Patterns of muscle-activity entrainment with locomotor and ventilatory events revealed (i)that the internal and external abdominal oblique muscles performed primarily locomotor functions during running yet their activity was entrained to expiration when the dogs were standing, (ii) that the internal and external intercostal, external oblique thoracic and transversus abdominis muscles performed both locomotor and respiratory functions simultaneously, (iii) that the parasternal internal intercostal muscle performed a primarily respiratory function (inspiration) and (iv) that the deep pectoralis and longissimus dorsi muscles performed only locomotor functions and were not active while the dogs were standing still. We conclude that the dual function of many hypaxial muscles may produce functional conflicts during running. The redundancy and complexity of the respiratory musculature as well as the particular pattern of respiratory—locomotor coupling in quadrupedal mammals may circumvent these conflicts or minimize their impact on respiration.
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Alves, Joseph Andrews, Barbara Ciralli Boerner, and Diego Andrés Laplagne. "Flexible Coupling of Respiration and Vocalizations with Locomotion and Head Movements in the Freely Behaving Rat." Neural Plasticity 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/4065073.
Full textAbstract:
Quadrupedal mammals typically synchronize their respiration with body movements during rhythmic locomotion. In the rat, fast respiration is coupled to head movements during sniffing behavior, but whether respiration is entrained by stride dynamics is not known. We recorded intranasal pressure, head acceleration, instantaneous speed, and ultrasonic vocalizations from male and female adult rats while freely behaving in a social environment. We used high-speed video recordings of stride to understand how head acceleration signals relate to locomotion and developed techniques to identify episodes of sniffing, walking, trotting, and galloping from the recorded variables. Quantitative analysis of synchrony between respiration and head acceleration rhythms revealed that respiration and locomotion movements were coordinated but with a weaker coupling than expected from previous work in other mammals. We have recently shown that rats behaving in social settings produce high rates of ultrasonic vocalizations during locomotion bouts. Accordingly, rats emitted vocalizations in over half of the respiratory cycles during fast displacements. We present evidence suggesting that emission of these calls disrupts the entrainment of respiration by stride. The coupling between these two variables is thus flexible, such that it can be overridden by other behavioral demands.
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Carrano, Matthew T. "Locomotion in non-avian dinosaurs: integrating data from hindlimb kinematics, in vivo strains, and bone morphology." Paleobiology 24, no. 4 (1998): 450–69. http://dx.doi.org/10.1017/s0094837300020108.
Full textAbstract:
Analyses of non-avian dinosaur locomotion have been hampered by the lack of an appropriate locomotor analog among extant taxa. Birds, though members of the clade Dinosauria, have undergone significant modifications in hindlimb osteology and musculature. These changes have resulted in a uniquely developed system of limb kinematics (involving a more horizontal femoral posture and knee-dominated limb motion), which precludes the direct use of extant birds as models for non-avian dinosaur locomotion. Analyses of locomotor data from extant birds and mammals suggest a causal link between general hindlimb kinematics, bone strains, and limb bone morphology among these taxa. A model is proposed that relates the amount of torsional loading in femora to bone orientation, such that torsion is maximal in horizontal femora and minimal in vertical femora. Since bone safety factors are lower for torsional shear strains than for longitudinal axial strains, an increase in torsion can potentially affect bone morphology dramatically over evolutionary time. Interpreting the nearly identical limb bone dimensions and limb element proportions of non-avian dinosaurs and mammals in the light of this relationship supports the prediction of similar vertical femoral postures and hip-driven limb kinematics in these two groups.This information can be used to interpret patterns of locomotor evolution within Dinosauria. The evolution of quadrupedalism with large body size and the acquisition of cursorial or graviportal limb morphologies occurred repeatedly but did not affect the underlying uniformity of dinosaur locomotor morphology. Only derived coelurosaurian theropods (paravians) developed significant modifications of the basic dinosaurian patterns of limb use. Changes in theropod hindlimb kinematics and posture apparently began shortly prior to the origin of flight, but did not acquire a characteristically modern avian aspect until after the later acquisition of derived flight characteristics.
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Funk, G. D., I. J. Valenzuela, and W. K. Milsom. "Energetic consequences of coordinating wingbeat and respiratory rhythms in birds." Journal of Experimental Biology 200, no. 5 (March 1, 1997): 915–20. http://dx.doi.org/10.1242/jeb.200.5.915.
Full textAbstract:
The coordination of ventilatory and locomotor rhythms has been documented in many birds and mammals. It has been suggested that the physiological significance of such coordination is a reduction in the cost of ventilation which confers an energetic advantage to the animal. We tested this hypothesis by measuring the external work required to ventilate birds mechanically during simulated flight. Patterns of wing motion and breathing were produced in which the relationship between wing motion and breathing was in phase and out of phase with the relationship seen during normal flight. Differences between the energetic costs of in-phase versus out-of-phase synchronization were particularly large (26 %) in instances where locomotion and respiration frequency were synchronized at one breath per wingbeat. The saving (9 %) obtained from in-phase versus out-of-phase coordination at the 3:1 coordination ratio seen normally in free-flying Canada geese was smaller but still supported the hypothesis that there is a significant net saving obtained from reducing the mechanical interference between locomotion and ventilation by locomotor­respiratory coupling.
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Smith, Shaylee K., and Vanessa K. Hilliard Young. "Balancing on a Limb: Effects of Gravidity on Locomotion in Arboreal, Limbed Vertebrates." Integrative and Comparative Biology 61, no. 2 (April 22, 2021): 573–78. http://dx.doi.org/10.1093/icb/icab035.
Full textAbstract:
Abstract Reproduction is linked to a plethora of costs in gravid females, not least of which is a reduction in locomotor performance. Locomotor constraints due to gravidity are apparent across aquatic, terrestrial, and arboreal habitats. Decrements to speed and maneuverability are the most often cited performance consequences of gravidity, regardless of habitat. Arboreal habitats present additional challenges, as they often are composed of unstable and varying substrates that affect locomotor performance. Many arboreal taxa exhibit morphological adaptations, such as grasping extremities and tails, that function to aid in stability during locomotion. Tail length has been found to correlate with lifestyle: arboreal mammals tend to have relatively longer tails compared with terrestrial counterparts. Balancing on a limb is hard on its own, but when combined with increased mass and shifts in center of mass due to pregnancy, it becomes even more challenging. However, few studies have explored the constraints that govern the intersection of arboreal locomotion, reproductive cost, and morphology. In this review, we identify fruitful areas for expansion of research and knowledge (i.e., the role of the tail) when it comes to arboreal balance during gestation.
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Carrier, David R. "The evolution of locomotor stamina in tetrapods: circumventing a mechanical constraint." Paleobiology 13, no. 3 (1987): 326–41. http://dx.doi.org/10.1017/s0094837300008903.
Full textAbstract:
Endothermic tetrapods differ dramatically from ectothermic tetrapods in having a great capacity to sustain vigorous locomotion. I suggest that this difference reflects alternative adaptive responses to a mechanical constraint that was an inherent consequence of the vertebrate transition from aquatic to terrestrial modes of locomotion and respiration. The earliest tetrapods may not have been able to walk and breathe at the same time. Their sprawling gait and lateral vertebral bending would have required unilateral contractions of the thoracic musculature that may have interfered with the bilateral movements necessary for breathing. Modern lizards, whose locomotor and respiratory anatomy resembles that of the early tetrapods, provide support for this hypothesis because their breathing is greatly reduced during locomotor activity. Tetrapod lineages that gave rise to modern ectotherms apparently retained the constraint, becoming either highly specialized for burst activity based on anaerobic metabolism or specialized in passive mechanisms of defense against predators. The lineages from which birds and mammals are derived have undergone morphological changes that enable simultaneous running and breathing. In modern tetrapods upright posture is correlated with endothermic metabolism. This correlation may have arisen to circumvent ancestral constraints on locomotor stamina.
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Alluin, Olivier, Hugo Delivet-Mongrain, and Serge Rossignol. "Inducing hindlimb locomotor recovery in adult rat after complete thoracic spinal cord section using repeated treadmill training with perineal stimulation only." Journal of Neurophysiology 114, no. 3 (September 2015): 1931–46. http://dx.doi.org/10.1152/jn.00416.2015.
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Although a complete thoracic spinal cord section in various mammals induces paralysis of voluntary movements, the spinal lumbosacral circuitry below the lesion retains its ability to generate hindlimb locomotion. This important capacity may contribute to the overall locomotor recovery after partial spinal cord injury (SCI). In rats, it is usually triggered by pharmacological and/or electrical stimulation of the cord while a robot sustains the animals in an upright posture. In the present study we daily trained a group of adult spinal (T7) rats to walk with the hindlimbs for 10 wk (10 min/day for 5 days/wk), using only perineal stimulation. Kinematic analysis and terminal electromyographic recordings revealed a strong effect of training on the reexpression of hindlimb locomotion. Indeed, trained animals gradually improved their locomotion while untrained animals worsened throughout the post-SCI period. Kinematic parameters such as averaged and instant swing phase velocity, step cycle variability, foot drag duration, off period duration, and relationship between the swing features returned to normal values only in trained animals. The present results clearly demonstrate that treadmill training alone, in a normal horizontal posture, elicited by noninvasive perineal stimulation is sufficient to induce a persistent hindlimb locomotor recovery without the need for more complex strategies. This provides a baseline level that should be clearly surpassed if additional locomotor-enabling procedures are added. Moreover, it has a clinical value since intrinsic spinal reorganization induced by training should contribute to improve locomotor recovery together with afferent feedback and supraspinal modifications in patients with incomplete SCI.
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Farmer, C. G., and J. W. Hicks. "Circulatory impairment induced by exercise in the lizard Iguana iguana." Journal of Experimental Biology 203, no. 17 (September 1, 2000): 2691–97. http://dx.doi.org/10.1242/jeb.203.17.2691.
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Mechanical integration of the cardiac, muscular and ventilatory pumps enables mammals to vary cardiac output over a wide range to match metabolic demands. We have found this integration lacking in a lizard (Iguana iguana) that differs from mammals because blood flow from the caudal body and ventilation are maximal after, rather than during, exercise. Because Iguana iguana are constrained from ventilation during intense locomotion, they appear to be unable to recruit the abdomen and thorax as a pump for venous return. This constraint on simultaneous running and costal breathing arises from their musculoskeletal design, which is similar to that of basal tetrapods, and so a constraint on venous return during exercise may be ancestral for tetrapods. We suggest that mechanical coupling of the pulmonary and cardiac pumps may have been important for the evolution of high-speed locomotor stamina in terrestrial vertebrates.
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Etienne, A. S., R. Maurer, and V. Séguinot. "Path integration in mammals and its interaction with visual landmarks." Journal of Experimental Biology 199, no. 1 (January 1, 1996): 201–9. http://dx.doi.org/10.1242/jeb.199.1.201.
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During locomotion, mammals update their position with respect to a fixed point of reference, such as their point of departure, by processing inertial cues, proprioceptive feedback and stored motor commands generated during locomotion. This so-called path integration system (dead reckoning) allows the animal to return to its home, or to a familiar feeding place, even when external cues are absent or novel. However, without the use of external cues, the path integration process leads to rapid accumulation of errors involving both the direction and distance of the goal. Therefore, even nocturnal species such as hamsters and mice rely more on previously learned visual references than on the path integration system when the two types of information are in conflict. Recent studies investigate the extent to which path integration and familiar visual cues cooperate to optimize the navigational performance.
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Jayne, B. C., and D. J. Irschick. "Effects of incline and speed on the three-dimensional hindlimb kinematics of a generalized iguanian lizard (Dipsosaurus dorsalis)." Journal of Experimental Biology 202, no. 2 (January 15, 1999): 143–59. http://dx.doi.org/10.1242/jeb.202.2.143.
Full textAbstract:
Lizards commonly move on steep inclines in nature, but no previous studies have investigated whether the kinematics of the limbs of lizards differ on inclined surfaces compared with level surfaces. Therefore, we examined how the kinematics of the hindlimb were affected by both incline (downhill 30 degrees, level and uphill 30 degrees) and different speeds of steady locomotion (50–250 cm s-1) in the morphologically generalized iguanian lizard Dipsosaurus dorsalis. On the uphill surface, the strides of lizards were shorter and quicker than those at a similar speed on the level and downhill surfaces. A multivariate analysis revealed that the kinematics of locomotion on all three inclines were distinct, but several kinematic features of locomotion on the downhill surface were especially unique. For example, downhill locomotion had the lowest angular excursions of femur rotation, and the knee and ankle were flexed more at footfall which contributed to a very low hip height. For D. dorsalis, changes in knee and ankle angles on the uphill surface were similar to those described previously for mammals moving up inclines, despite fundamental differences in limb posture between most mammals and lizards. Several features of the kinematics of D. dorsalis suggest that a sprawling limb enhances the ability to move on inclines.
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Akay, Turgay, and Andrew J. Murray. "Relative Contribution of Proprioceptive and Vestibular Sensory Systems to Locomotion: Opportunities for Discovery in the Age of Molecular Science." International Journal of Molecular Sciences 22, no. 3 (February 2, 2021): 1467. http://dx.doi.org/10.3390/ijms22031467.
Full textAbstract:
Locomotion is a fundamental animal behavior required for survival and has been the subject of neuroscience research for centuries. In terrestrial mammals, the rhythmic and coordinated leg movements during locomotion are controlled by a combination of interconnected neurons in the spinal cord, referred as to the central pattern generator, and sensory feedback from the segmental somatosensory system and supraspinal centers such as the vestibular system. How segmental somatosensory and the vestibular systems work in parallel to enable terrestrial mammals to locomote in a natural environment is still relatively obscure. In this review, we first briefly describe what is known about how the two sensory systems control locomotion and use this information to formulate a hypothesis that the weight of the role of segmental feedback is less important at slower speeds but increases at higher speeds, whereas the weight of the role of vestibular system has the opposite relation. The new avenues presented by the latest developments in molecular sciences using the mouse as the model system allow the direct testing of the hypothesis.
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França de Barros, Filipa, Julien Bacqué-Cazenave, Coralie Taillebuis, Gilles Courtand, Marin Manuel, Hélène Bras, Michele Tagliabue, Denis Combes, François M. Lambert, and Mathieu Beraneck. "Conservation of locomotion-induced oculomotor activity through evolution in mammals." Current Biology 32, no. 2 (January 2022): 453–61. http://dx.doi.org/10.1016/j.cub.2021.11.022.
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Schilling, N. "Ontogenetic development of locomotion in small mammals - a kinematic study." Journal of Experimental Biology 208, no. 21 (November 1, 2005): 4013–34. http://dx.doi.org/10.1242/jeb.01875.
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Abourachid, A., M. Herbin, R. Hackert, L. Maes, and V. Martin. "Experimental study of coordination patterns during unsteady locomotion in mammals." Journal of Experimental Biology 210, no. 2 (January 15, 2007): 366–72. http://dx.doi.org/10.1242/jeb.02632.
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Jordan, Larry M., Jun Liu, Peter B. Hedlund, Turgay Akay, and Keir G. Pearson. "Descending command systems for the initiation of locomotion in mammals." Brain Research Reviews 57, no. 1 (January 2008): 183–91. http://dx.doi.org/10.1016/j.brainresrev.2007.07.019.
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McADAM, ANDREW G., and DONALD L. KRAMER. "Vigilance as a benefit of intermittent locomotion in small mammals." Animal Behaviour 55, no. 1 (January 1998): 109–17. http://dx.doi.org/10.1006/anbe.1997.0592.
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Arregui, Marina, Emily M. Singleton, Pedro Saavedra, D. Ann Pabst, Michael J. Moore, Eva Sierra, Miguel A. Rivero, et al. "Myoglobin Concentration and Oxygen Stores in Different Functional Muscle Groups from Three Small Cetacean Species." Animals 11, no. 2 (February 9, 2021): 451. http://dx.doi.org/10.3390/ani11020451.
Full textAbstract:
Compared with terrestrial mammals, marine mammals possess increased muscle myoglobin concentrations (Mb concentration, g Mb · 100g−1 muscle), enhancing their onboard oxygen (O2) stores and their aerobic dive limit. Although myoglobin is not homogeneously distributed, cetacean muscle O2 stores have been often determined by measuring Mb concentration from a single muscle sample (longissimus dorsi) and multiplying that value by the animal’s locomotor muscle or total muscle mass. This study serves to determine the accuracy of previous cetacean muscle O2 stores calculations. For that, body muscles from three delphinid species: Delphinus delphis, Stenella coeruleoalba, and Stenella frontalis, were dissected and weighed. Mb concentration was calculated from six muscles/muscle groups (epaxial, hypaxial and rectus abdominis; mastohumeralis; sternohyoideus; and dorsal scalenus), each representative of different functional groups (locomotion powering swimming, pectoral fin movement, feeding and respiration, respectively). Results demonstrated that the Mb concentration was heterogeneously distributed, being significantly higher in locomotor muscles. Locomotor muscles were the major contributors to total muscle O2 stores (mean 92.8%) due to their high Mb concentration and large muscle masses. Compared to this method, previous studies assuming homogenous Mb concentration distribution likely underestimated total muscle O2 stores by 10% when only considering locomotor muscles and overestimated them by 13% when total muscle mass was considered.
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Ginot, Samuel, Lionel Hautier, Laurent Marivaux, and Monique Vianey-Liaud. "Ecomorphological analysis of the astragalo-calcaneal complex in rodents and inferences of locomotor behaviours in extinct rodent species." PeerJ 4 (October 11, 2016): e2393. http://dx.doi.org/10.7717/peerj.2393.
Full textAbstract:
Studies linking postcranial morphology with locomotion in mammals are common. However, such studies are mostly restricted to caviomorphs in rodents. We present here data from various families, belonging to the three main groups of rodents (Sciuroidea, Myodonta, and Ctenohystrica). The aim of this study is to define morphological indicators for the astragalus and calcaneus, which allow for inferences to be made about the locomotor behaviours in rodents. Several specimens were dissected and described to bridge the myology of the leg with the morphology of the bones of interest. Osteological characters were described, compared, mechanically interpreted, and correlated with a “functional sequence” comprising six categories linked to the lifestyle and locomotion (jumping, cursorial, generalist, fossorial, climber and semi-aquatic). Some character states are typical of some of these categories, especially arboreal climbers, fossorial and “cursorial-jumping” taxa. Such reliable characters might be used to infer locomotor behaviours in extinct species. Linear discriminant analyses (LDAs) were used on a wider sample of species and show that astragalar and calcaneal characters can be used to discriminate the categories among extant species whereasa posterioriinferences on extinct species should be examined with caution.