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Introduction: Non-invasive brain stimulation can modulate both neural processing and behavioral performance. Its effects may be influenced by the stimulated area and hemisphere. In this study (EC no. 09083), repetitive transcranial magnetic stimulation (rTMS) was applied to the primary motor cortex (M1) or dorsal premotor cortex (dPMC) of either the right or left hemisphere, while evaluating cortical neurophysiology and hand function.
Methods: Fifteen healthy subjects participated in this placebo-controlled crossover study. Four sessions of real 1 Hz rTMS (110% of rMT, 900 pulses) over (i) left M1, (ii) right M1, (iii) left dPMC, (iv) right dPMC, and one session of (v) placebo 1 Hz rTMS (0% of rMT, 900 pulses) over the left M1 were applied in randomized order. Motor function of both hands (Jebsen-Taylor Hand Function Test (JTHFT)) and neural processing within both hemispheres (motor evoked potentials (MEPs), cortical silent period (CSP), and ipsilateral silent period (ISP)) were evaluated prior and after each intervention session.
Results: A lengthening of CSP and ISP durations within the right hemisphere was induced by 1 Hz rTMS over both areas and hemispheres. No such intervention-induced neurophysiological changes were detected within the left hemisphere. Regarding JTHFT and MEP, no intervention-induced changes ensued. Changes of hand function correlated with neurophysiological changes within both hemispheres, more often for the left than the right hand.
Conclusions: Effects of 1 Hz rTMS can be better captured by neurophysiological than behavioral measures. Hemispheric differences need to be considered for this intervention.
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http://dx.doi.org/10.3390/brainsci13050752 | DOI Listing |
Commun Biol
September 2025
Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg - Martinsried, Germany.
The internal resistance of axons to ionic current flow determines action potential conduction velocity. Although mitochondria support axonal function, axons have been modeled as organelle-free cables, and mitochondrial impact on conduction velocity, specifically by increasing internal resistance, remains understudied. We combine computational modeling and electron microscopy of forebrain premotor axons controlling birdsong production.
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Department of Physiology, University of Bern, Bern, Switzerland.
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Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, UK.
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Biomedical Device Technology, Istanbul Aydın University, Istanbul, 34093, Istanbul, Turkey. Electronic address:
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Center for Studies in Behavioural Neurobiology, Department of Psychology, Concordia University, Montreal, QC, Canada, H4B 1R6
Adaptive behavior depends on a dynamic balance between acquisition and extinction memories. Male and female rodents differ in extinction learning rates, suggestion potential sex-based differences in this balance. In males, deletion of extinction-recruited neurons in the central nucleus (CN) of the amygdala impairs extinction retrieval, shifting behavior toward acquisition (Lay et al.
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