Brain Stimul
-
Stimulation of the vagus nerve via implanted electrodes is currently used to treat refractory epilepsy and depression. Recently, a non-invasive approach to vagal stimulation has demonstrated similar beneficial effects, but it remains unclear whether these effects are mediated via activation of afferent vagal fibers. ⋯ The present findings provide evidence in humans that cervical vagal afferents can be accessed non-invasively via transcutaneous electrical stimulation of the antero-lateral surface of the neck, which overlies the course of the nerve, suggesting an alternative and feasible method of stimulating vagal afferents.
-
Transcranial direct current stimulation (tDCS) has been used to alter the excitability of neurons within the cerebral cortex. Improvements in motor learning have been found in multiple studies when tDCS was applied to the motor cortex before or during task learning. The motor cortex is also active during the performance of motor imagination, a cognitive task during which a person imagines, but does not execute, a movement. Motor imagery can be used with noninvasive brain computer interfaces (BCIs) to control virtual objects in up to three dimensions, but to master control of such devices requires long training times. ⋯ These results suggest that unilateral tDCS over the sensorimotor motor cortex differentially affects cortical areas based on task specific neural activation.
-
Transcranial direct current stimulation (tDCS) is a popular non-invasive brain stimulation technique that has been shown to influence cortical excitability. While polarity specific effects have often been reported, this is not always the case, and variability in both the magnitude and direction of the effects have been observed. ⋯ Our findings indicate that although 2 mA anodal tDCS is effective at increasing cortical excitability at group level, the effects are unreliable across repeated testing sessions within individual participants. Our results suggest that 2 mA cathodal tDCS does not significantly alter cortical excitability immediately following stimulation and that there is poor reliability of the effect within the same individual across different testing sessions.
-
Why are weak sensory stimuli sometimes perceived and other times not? Experimental paradigms using near-threshold stimuli suggest that spontaneous brain network dynamics are involved in separating relevant from irrelevant information. Recent findings in human visual perception provide evidence that the immediate spontaneous brain state, i.e. the phase of alpha oscillations, predicts whether a coinciding stimulus is further processed or not. ⋯ Our data indicate that tACS applied at an endogenous frequency is capable of modulating human somatosensory perception by inducing phase-dependent periods of excitation and inhibition, i.e. entraining ongoing mu-alpha oscillations. These findings support the idea that the "pulsed inhibition" framework for sensory gating applies to somatosensory mu-alpha oscillations and might therefore represent a general, but sensory-specific mechanism of conscious human perception.
-
Review Meta Analysis
Non-Invasive Brain Stimulation Improves Paretic Limb Force Production: A Systematic Review and Meta-Analysis.
Non-invasive brain stimulation (NIBS) facilitates motor improvements post stroke. Transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) are representative NIBS techniques frequently used in stroke motor rehabilitation. Our primary question is: Do these two techniques improve force production capability in paretic limbs? ⋯ Cumulative meta-analytic results revealed that tDCS and rTMS rehabilitation protocols successfully improved paretic limb force production capabilities.