Motor training results in encoding of motor memories, a form of use-dependent plasticity. Here we tested the hypothesis that transcranial magnetic stimulation (TMS) synchronously applied to a motor cortex engaged in a motor training task could enhance this plastic process. Healthy volunteers were studied in four sessions: training consisting of performance of directionally specific voluntary thumb movements (Train alone), training with TMS delivered during the execution of the training movement in a strictly temporal relationship to the motor cortex contralateral (Train+TMS synchronous(contra)) and ipsilateral (Train+TMS synchronous(ipsi)) to the training hand, and training with TMS delivered asynchronous to the training movement to the motor cortex contralateral to the training hand (Train+TMS asynchronous(contra)). Train alone, Train+TMS synchronous(contra), and Train+TMS asynchronous(contra) but not Train+TMS synchronous(ipsi) elicited a clear motor memory. The longevity of the encoded memory was significantly enhanced by Train+TMS synchronous(contra) when compared with Train alone and Train+TMS asynchronous(contra). Therefore use-dependent encoding of a motor memory can be enhanced by synchronous Hebbian stimulation of the motor cortex that drives the training task and reduced by stimulation of the homologous ipsilateral motor cortex, a result relevant for studies of cognitive and physical rehabilitation.
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http://dx.doi.org/10.1152/jn.01038.2003 | DOI Listing |
Ann Neurol
January 2025
Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA.
Hum Brain Mapp
January 2025
Department of Psychology, Concordia University, Montreal, Quebec, Canada.
The cortex and cerebellum are densely connected through reciprocal input/output projections that form segregated circuits. These circuits are shown to differentially connect anterior lobules of the cerebellum to sensorimotor regions, and lobules Crus I and II to prefrontal regions. This differential connectivity pattern leads to the hypothesis that individual differences in structure should be related, especially for connected regions.
View Article and Find Full Text PDFJ Alzheimers Dis
January 2025
Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Background: White matter hyperintensities (WMH) are prominent neuroimaging markers of cerebral small vessel disease (CSVD) linked to cognitive decline. Nevertheless, the pathophysiological mechanisms underlying WMH remain unclear.
Objective: This study aimed to assess the structural decoupling index (SDI) as a novel metric for quantifying the brain's hierarchical organization associated with WMH in cognitively normal older adults
Methods: We analyzed data from 112 cognitively normal individuals with varying WMH burdens (43 high WMH burden and 69 low WMH burden).
Brain Behav
January 2025
Department of Neuroradiology, School of Medicine and Health, Technical University of Munich, Munich, Germany.
Purpose: Due to the highly individualized clinical manifestation of Parkinson's disease (PD), personalized patient care may require domain-specific assessment of neurological disability. Evidence from magnetic resonance imaging (MRI) studies has proposed that heterogenous clinical manifestation corresponds to heterogeneous cortical disease burden, suggesting customized, high-resolution assessment of cortical pathology as a candidate biomarker for domain-specific assessment.
Method: Herein, we investigate the potential of the recently proposed Mosaic Approach (MAP), a normative framework for quantifying individual cortical disease burden with respect to a population-representative cohort, in predicting domain-specific clinical progression.
Med Sci Monit
January 2025
Department of Rehabilitation, Guizhou Medical University, Guiyang, Guizhou, China.
BACKGROUND Swallowing is a complex behavior involving the musculoskeletal system and higher-order brain functions. We investigated the effects of different modalities of repetitive transcranial magnetic stimulation (rTMS) on the unaffected hemisphere and observed correlation between suprahyoid muscle activity and cortical activation in unilateral stroke patients when swallowing saliva, based on functional near-infrared spectroscopy (fNIRS). MATERIAL AND METHODS From November 2022 to March 2023, twenty-five patients with unilateral stroke were screened using computed tomography or magnetic resonance imaging and identified via a video fluoroscopic swallow study.
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