Larval Drosophila move up attractive chemical gradients, and down aversive ones. Although their movement is often characterized as a series of runs and directed turns, it can also be modeled as a continuous modulation of turning extent by the detected change in stimulus intensity as the animal moves through the gradient. We show that a neuromechanical model of peristaltic crawling and spontaneous bending in the larva can be adapted to produce taxis behavior by the simple addition of a local segmental reflex to modulate transverse viscosity (or "bendiness") proportionally to the intensity change detected in the head. Altering the gain produces weaker or stronger, negative or positive taxis, with behavioral statistics that qualitatively match the larva.
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http://dx.doi.org/10.1093/icb/icy094 | DOI Listing |
J Clin Med
December 2024
Mechanical Engineering Department, Auburn University, Auburn, AL 36849, USA.
The accurate, repeatable, and cost-effective quantitative characterization of mild traumatic brain injuries (mTBIs) is crucial for safeguarding the long-term health and performance of high-risk groups, including athletes, emergency responders, and military personnel. However, gaps remain in optimizing mTBI assessment methods, especially regarding the integration of neuromechanical metrics such as reaction time (RT) in predictive models. This review synthesizes existing research on the use of neuromechanical probabilistic models as tools for assessing mTBI, with an emphasis on RT's role in predictive diagnostics.
View Article and Find Full Text PDFJ Physiol
December 2024
School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
Previous studies established strong links between morphological characteristics of mammalian hindlimb muscles and their sensorimotor functions during locomotion. Less is known about the role of forelimb morphology in motor outputs and generation of sensory signals. Here, we measured morphological characteristics of 46 forelimb muscles from six cats.
View Article and Find Full Text PDFGait Posture
December 2024
Department of Integrative Physiology, University of Colorado Boulder, CO, USA. Electronic address:
Background: Electromyographic (EMG) recordings indicate that both the flexor digitorum brevis and soleus muscles contribute significantly to the control of standing balance, However, less is known about the adjustments in EMG activity of these two muscles across different postures.
Research Question: The purpose of our study was to use deep-learning models to distinguish between the EMG activity of the flexor digitorum brevis and soleus muscles across four standing postures.
Methods: Deep convolutional neural networks were employed to classify standing postures based on the temporal and spatial features embedded in high-density surface EMG signals.
J Biomech
January 2025
Joint Department of Biomedical Engineering, UNC Chapel Hill & NC State University, Chapel Hill, NC, USA. Electronic address:
Forward propulsion depends on the forces generated by the triceps surae muscles and transmitted through the muscles' subtendons, which merge and twist to form the Achilles tendon (AT). As people age, the AT may undergo structural changes that could alter the subtendons' ability to transmit forces or function with some independence; prominent changes include increased tendon compliance and a proliferation of interfascicular adhesions compared to younger tendon. However, the effects of age-related changes on the subtendons are difficult to isolate in vivo.
View Article and Find Full Text PDFExp Brain Res
November 2024
Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 80309, USA.
The purpose of our study was to evaluate the accuracy with which classification algorithms could distinguish among standing postures based on center-of-pressure (CoP) trajectories. We performed a secondary analysis of published data from three studies: Study A) assessment of balance control on firm or foam surfaces with eyes-open or closed, Study B) quantification of postural sway in forward-backward and side-to-side directions during four standing-balance tasks that differed in difficulty, and Study C) an evaluation of the impact of two modes of transcutaneous electrical nerve stimulation on balance control in older adults. Three classification algorithms (decision tree, random forest, and k-nearest neighbor) were used to classify standing postures based on the extracted features from CoP trajectories in both the time and time-frequency domains.
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