It has been hypothesized that the central nervous system simplifies the production of movement by limiting motor commands to a small set of modules known as muscle synergies. Recently, investigators have questioned whether a low-dimensional controller can produce the rich and flexible behaviours seen in everyday movements. To study this issue, we implemented muscle synergies in a biomechanically realistic model of the human upper extremity and performed computational experiments to determine whether synergies introduced task performance deficits, facilitated the learning of movements, and generalized to different movements. We derived sets of synergies from the muscle excitations our dynamic optimizations computed for a nominal task (reaching in a plane). Then we compared the performance and learning rates of a controller that activated all muscles independently to controllers that activated the synergies derived from the nominal reaching task. We found that a controller based on synergies had errors within 1 cm of a full-dimensional controller and achieved faster learning rates (as estimated from computational time to converge). The synergy-based controllers could also accomplish new tasks-such as reaching to targets on a higher or lower plane, and starting from alternative initial poses-with average errors similar to a full-dimensional controller.
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http://dx.doi.org/10.1098/rsif.2020.0011 | DOI Listing |
Lung Cancer
January 2025
Internal Medicine III, Wakayama Medical University, Wakayama, Japan.
Objectives: The lack of definitive biomarkers presents a significant challenge for chemo-immunotherapy in extensive-stage small-cell lung cancer (ES-SCLC). We aimed to identify key genes associated with chemo-immunotherapy efficacy in ES-SCLC through comprehensive gene expression analysis using machine learning (ML).
Methods: A prospective multicenter cohort of patients with ES-SCLC who received first-line chemo-immunotherapy was analyzed.
J Exp Child Psychol
January 2025
Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, LMU University Hospital, LMU Munich, 80336 München, Germany.
Early spelling depends on the ability to understand the alphabetic principle and to translate speech sounds into visual symbols (letters). Thus, the ability to associate sound-symbol pairs might be an important predictor of spelling development. Here, we examined the relation between sound-symbol learning (SSL) and early spelling skills.
View Article and Find Full Text PDFSimul Healthc
December 2024
From the Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.D.M., I.V.H., L.D., W.W.); Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium (I.V.H., L.D.); Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (P.V.d.V.); Department of Emergency Medicine, Ghent University Hospital, Ghent, Belgium (P.V.d.V.); Department of Gastrointestinal Surgery, Ghent University Hospital, Ghent, Belgium (H.V., W.W.); Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (L.K.); and Copenhagen Academy for Medical Education and Simulation (CAMES), Copenhagen, Denmark (L.K.).
Introduction: Chest tube insertions (CTIs) have a high complication rate, prompting the training of technical skills in simulated settings. However, assessment tools require validity evidence prior to their implementation. This study aimed to collect validity evidence for assessment of technical skills in CTI on Thiel-embalmed human bodies.
View Article and Find Full Text PDFCir Cir
January 2025
Departamento de Cirugía Hepatopancreatobiliar, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Ciudad de México, México.
Objective: Minimally invasive liver resection is employed worldwide for the management of benign and malignant liver lesions. There is no description of postoperative outcomes in the Mexican population. This study aims to report the initial experience in Mexico.
View Article and Find Full Text PDFJ Speech Lang Hear Res
January 2025
Department of Psychology, University of Western Ontario, London, Canada.
Purpose: Recent advances in artificial intelligence provide opportunities to capture and represent complex features of human language in a more automated manner, offering potential means of improving the efficiency of language assessment. This review article presents computerized approaches for the analysis of narrative language and identification of language disorders in children.
Method: We first describe the current barriers to clinicians' use of language sample analysis, narrative language sampling approaches, and the data processing stages that precede analysis.
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