Brain Stimul
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Motor cortex stimulation (MCS) is a potentially effective treatment for chronic neuropathic pain. The neural mechanisms underlying the reduction of hyperalgesia and allodynia after MCS are not completely understood. ⋯ These findings suggest that, in animals with SCL, MCS attenuates hypersensitivity by suppressing activity in the primary somatosensory cortex and prefrontal cortex.
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Randomized Controlled Trial
Characterizing the mechanisms of central and peripheral forms of neurostimulation in chronic dysphagic stroke patients.
Swallowing problems following stroke may result in increased risk of aspiration pneumonia, malnutrition, and dehydration. ⋯ In this mechanistic study, an increase in corticobulbar excitability the unaffected projection was correlated with the improvement in swallowing safety (P = .001, rho = -.732), but modality-specific differences were observed. Paradigms providing peripheral input favored change in neurophysiological and behavioral outcome measures in chronic dysphagia patients. Further larger cohort studies of neurostimulation in chronic dysphagic stroke are imperative.
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Randomized Controlled Trial
Anodal transcranial direct current stimulation (tDCS) over the motor cortex increases sympathetic nerve activity.
Transcranial direct current stimulation (tDCS) is currently being investigated as a non-invasive neuromodulation therapy for a range of conditions including stroke rehabilitation. tDCS affects not only the area underlying the electrodes but also other areas of the cortex and subcortical structures. This could lead to unintended alteration in brain functions such as autonomic control. ⋯ Anodal tDCS of the motor cortex shifts autonomic nervous system balance toward sympathetic dominance due at least in part to an increase in sympathetic output. These results suggest further investigation is warranted on tDCS use in patient groups with potential autonomic dysfunction, such as stroke patients.
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TMS activations of white matter depend not only on the distance from the coil, but also on the orientation of the axons relative to the TMS-induced electric field, and especially on axonal bends that create strong local field gradient maxima. Therefore, tractography contains potentially useful information for TMS targeting. ⋯ Diffusion MRI tractography with electromagnetic modeling may improve spatial specificity and efficacy of TMS.
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In this study we tested the hypothesis whether a lasting change in the excitability of cortical output circuits can be obtained in healthy humans by combining a peripheral nerve stimulation during a concomitant depolarization and/or hyperpolarization of motor cortex. To reach this aim we combined two different neurophysiological techniques each of them able to induce a lasting increase of cortical excitability by them self: namely median nerve repetitive electrical stimulation (rEPNS) and transcranial direct current stimulation (tDCS). Ten normal young volunteers were enrolled in the present study. ⋯ Anodal or cathodal tDCS + rEPNS and sham tDCS + rEPNS caused a lasting facilitation of H-reflex. These findings suggest that by providing afferent input to the motor cortex while its excitability level is increased or decreased by tDCS may be a highly effective means for inducing an enduring bi-directional plasticity. The mechanism of this protocol may be complex, involving either cortical and spinal after effects.