The human body exploits its neural mechanisms to optimize actions. Rhythmic movements are optimal when their frequency is close to the natural frequency of the system. In a pendulum, gravity modulates this spontaneous frequency. Participants unconsciously adjust their natural pace when cyclically moving the arm in altered gravity. However, the timescale of this adaptation is unexplored. Participants performed cyclic movements before, during, and after fast transitions between hypergravity levels (1g-3g and 3g-1g) induced by a human centrifuge. Movement periods were modulated with the average value of gravity during transitions. However, while participants increased movement pace on a cycle basis when gravity increased (1g-3g), they did not decrease pace when gravity decreased (3g-1g). We highlight asymmetric effects in the spontaneous adjustment of movement dynamics on short timescales, suggesting the involvement of cognitive factors, beyond standard dynamical models.
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http://dx.doi.org/10.1016/j.isci.2024.109618 | DOI Listing |
J Neuroinflammation
January 2025
Department of Neuroscience and Experimental Therapeutics, School of Medicine, Texas A&M Health Science Center, Bryan, TX, 77807-3260, USA.
Background: Disturbances of the sleep-wake cycle and other circadian rhythms typically precede the age-related deficits in learning and memory, suggesting that these alterations in circadian timekeeping may contribute to the progressive cognitive decline during aging. The present study examined the role of immune cell activation and inflammation in the link between circadian rhythm dysregulation and cognitive impairment in aging.
Methods: C57Bl/6J mice were exposed to shifted light-dark (LD) cycles (12 h advance/5d) during early adulthood (from ≈ 4-6mo) or continuously to a "fixed" LD12:12 schedule.
Parkinsonism Relat Disord
January 2025
Unit of Neurorehabilitation, Bambino Gesù Children's Hospital, IRCCS, Rome, 00165, Italy.
Segmental Brainstem Myoclonus (SBM) is a rare movement disorder characterized by rhythmic contractions of muscles innervated by brainstem segments. We report a 20-year-old patient with ADCK3-related spinocerebellar ataxia type 9 (SCAR9) presenting with sudden-onset myoclonic movements of the throat, tongue, and soft palate. Brain MRI showed stable findings, including dentate nucleus hyperintensities.
View Article and Find Full Text PDFBrain Behav
January 2025
School of Psychology, University of Nottingham University Park, Nottingham, UK.
Background: Rhythmic median nerve stimulation (MNS) at 10 Hz has been shown to cause a substantial reduction in tic frequency in individuals with Tourette syndrome. The mechanism of action is currently unknown but is hypothesized to involve entrainment of oscillations within the sensorimotor cortex.
Objective: We used functional magnetic resonance spectroscopy (fMRS) to explore the dynamic effects of MNS on neurometabolite concentrations.
PLoS One
January 2025
DHI Water and Environment Inc, Cambridge, Canada.
The water quality and resources of Lake Ontario's nearshore ecosystem undergo heightened stress, particularly along the northwest shoreline. Hydrodynamic processes linking the distinct nearshore and offshore trophic structures play a crucial role in transporting nutrient-loaded water along and across the shore. Despite the pivotal connection between algae growth and the development of nuisance proportions, the scales over which these processes operate remain poorly understood.
View Article and Find Full Text PDFNat Commun
January 2025
School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China.
East, South, and Southeast Asia (together referred to as Southeastern Asia hereafter) have been recognized as critical areas fuelling the global circulation of seasonal influenza. However, the seasonal influenza migration network within Southeastern Asia remains unclear, including how pandemic-related disruptions altered this network. We leveraged genetic, epidemiological, and airline travel data between 2007-2023 to characterise the dispersal patterns of influenza A/H3N2 and B/Victoria viruses both out of and within Southeastern Asia, including during perturbations by the 2009 A/H1N1 and COVID-19 pandemics.
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