Healthy aging is associated with a progressive decline in motor performance and thermoregulatory efficiency. Functional consequences of severe whole-body hyperthermia on neurophysiological functions in healthy aged men have not been investigated. To determine whether severe whole-body hyperthermia (increase in rectal temperature of about 2.5 °C) induced by lower-body heating in older men (64-80 years, n = 9) would suppress excitability of reflexes, voluntarily and electrically induced ankle plantar flexor contractile properties were compared with those in young men (19-21 years, n = 11). Though no aging effect on hyperthermia-induced reflex amplitudes was observed, a decrease in maximal H-reflex and V-wave latencies was found to be greater in older than in young men. In older men, lower-body heating was accompanied by a significant increase in twitch and tetani test torque in parallel with a greater decrease in muscle contraction time. There was no temperature-depended aging effect on the voluntary activation and maximal voluntary torque production. Despite delayed and weakened thermoregulation and age-related decline in neuromuscular function, motor performance in whole-body severe hyperthermia is apparently preserved in healthy aging.
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http://dx.doi.org/10.1080/02656736.2018.1533650 | DOI Listing |
J Prev Alzheimers Dis
January 2025
Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Alzheimer's Disease Research Center at the Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA.
Background: Declining motor abilities might be a noninvasive biomarker for Alzheimer's disease (AD). Studying motor ability and AD progression in younger Latinos with autosomal dominant Alzheimer's disease (ADAD) can provide insights into the interplay between motor ability and cognition in individuals with minimal confounding from age-normative changes and comorbid medical conditions.
Objectives: This study aimed to (1) examine motor abilities as a function of years to dementia diagnosis and (2) examine associations between motor ability and cognitive performance.
Neuroimage
January 2025
Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA; College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA; Department of Pharmacology & Neuroscience, Creighton University, Omaha, NE, USA. Electronic address:
Noninvasive brain stimulation of the primary motor cortex has been shown to alter therapeutic outcomes in stroke and other neurological conditions, but the precise mechanisms remain poorly understood. Determining the impact of such neurostimulation on the neural processing supporting motor control is a critical step toward further harnessing its therapeutic potential in multiple neurological conditions affecting the motor system. Herein, we leverage the excellent spatio-temporal precision of magnetoencephalographic (MEG) imaging to identify the spectral, spatial, and temporal effects of high-definition transcranial direct current stimulation (HD-tDCS) on the neural responses supporting motor control.
View Article and Find Full Text PDFJ Affect Disord
January 2025
Centre for Clinical Neurosciences, McMaster University, Canada; Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada; Mood Disorders Treatment and Research Centre and Women's Health Concerns Clinic, St. Joseph's Healthcare Hamilton, ON, Canada. Electronic address:
Background: Neurofilament light chain (NfL) is a cytoskeletal protein that supports neuronal structure. Blood NfL levels are reported to be higher in diseases where myelin is damaged. Studies investigating intracortical myelin (ICM) in bipolar disorder (BD) have reported deficits in ICM maturation over age.
View Article and Find Full Text PDFJ Electromyogr Kinesiol
January 2025
Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road E, Guelph, ON N1G 2W1, Canada. Electronic address:
Rate of torque development (RTD) measures how rapidly one can generate torque and is crucial for balance and athletic performance. Fast RTD depends on the rapid recruitment of high threshold motor units (MUs). Cutaneous electrical stimulation has been shown to alter MU excitability, favoring high threshold MUs via reduced recruitment thresholds.
View Article and Find Full Text PDFMol Ther
January 2025
Program of Cellular and Molecular Biology, Biomedical Sciences Institute (ICBM), Universidad de Chile, Santiago, Chile; Biomedical Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile; FONDAP Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Buck Institute for Research on Aging, Novato, CA, USA. Electronic address:
Amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia (FTD) are part of a spectrum of diseases that share several causative genes, resulting in a combinatory of motor and cognitive symptoms and abnormal protein aggregation. Multiple unbiased studies have revealed that proteostasis impairment at the level of the endoplasmic reticulum (ER) is a transversal pathogenic feature of ALS/FTD. The transcription factor XBP1s is a master regulator of the unfolded protein response (UPR), the main adaptive pathway to cope with ER stress.
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