Background and Purpose— Although there is some early evidence showing the value of repetitive transcranial magnetic stimulation (rTMS) in stroke rehabilitation, the therapeutic effect of high-frequency rTMS, along with the physiology of rTMS-induced corticomotor excitability supporting motor learning in stroke, has not been established. This study investigated high-frequency rTMS-induced cortical excitability and the associated motor skill acquisition in chronic stroke patients. Methods— Fifteen patients with chronic hemiparetic stroke (13 men; mean age 53.5 years) practiced a complex, sequential finger motor task using their paretic fingers either after 10 Hz or sham rTMS over the contralateral primary motor cortex (M1). Both the changes in the behavior and corticomotor excitability before and after the intervention were examined by measuring the movement accuracy, the movement time, and the motor-evoked potential (MEP) amplitude. A separate repeated-measures ANOVA and correlation statistics were used to determine the main and interaction effects as well as relationship between the changes in the behavioral and corticomotor excitability. Results— High-frequency rTMS resulted in a significantly larger increase in the MEP amplitude than the sham rTMS ( P <0.01), and the plastic change was positively associated with an enhanced motor performance accuracy ( P <0.05). Conclusions— High-frequency rTMS of the affected motor cortex can facilitate practice-dependent plasticity and improve the motor learning performance in chronic stroke victims.

The time-dependent effect of transcranial direct current stimulation (tDCS) on working memory was investigated by applying anodal stimulation over the left prefrontal cortex. This single-blind, sham-controlled crossover study recruited 15 healthy participants. A three-back verbal working-memory task was performed before, during, and 30 min after 1 mA anodal or sham tDCS. Anodal tDCS, compared with sham stimulation, significantly improved working-memory performance. Accuracy of response was significantly increased after 20 min of tDCS application, and was further enhanced after 30 min of stimulation. This effect was maintained for 30 min after the completion of stimulation. These results suggest that tDCS at 1 mA enhances working memory in a time-dependent manner for at least 30 min in healthy participants.

Background. This study aimed to delineate the cerebral attentional network in patients with traumatic brain injury (TBI) and assess for adaptations in this network in response to a rehabilitation intervention. Methods. Seventeen patients with TBI and 15 healthy subjects underwent functional magnetic resonance imaging (fMRI) using a visuospatial attention task. Ten TBI patients who successfully completed attentional training had a follow-up fMRI. Results. In the TBI patients, fMRI analysis showed more activation in the frontal and temporoparietal lobes, as well as less activation in the anterior cingulated gyrus, SMA, and temporooccipital regions compared to the healthy subjects. Following cognitive training, the TBI patients improved performance of attention tasks accompanied by changes in attentional network activation; the activity of the frontal lobe decreased, whereas activation of the anterior cingulate cortices and precuneus increased. Conclusions. These findings demonstrate the plasticity and training induced redistribution of the visuospatial attentional network in TBI patients.

Transcranial magnetic stimulation (TMS) is a useful tool to induce and measure plasticity in the human brain. However, the cortical effects are generally indirectly evaluated with motor‐evoked potentials (MEPs) reflective of modulation of cortico‐spinal excitability. In this study, we aim to provide direct measures of cortical plasticity by combining TMS with electroencephalography (EEG). Continuous theta‐burst stimulation (cTBS) was applied over the primary motor cortex (M1) of young healthy adults, and we measured modulation of (i) MEPs, (ii) TMS‐induced EEG evoked potentials (TEPs), (iii) TMS‐induced EEG synchronization and (iv) eyes‐closed resting EEG. Our results show the expected cTBS‐induced decrease in MEP size, which we found to be paralleled by a modulation of a combination of TEPs. Furthermore, we found that cTBS increased the power in the theta band of eyes‐closed resting EEG, whereas it decreased single‐pulse TMS‐induced power in the theta and alpha bands. In addition, cTBS decreased the power in the beta band of eyes‐closed resting EEG, whereas it increased single‐pulse TMS‐induced power in the beta band. We suggest that cTBS acts by modulating the phase alignment between already active oscillators; it synchronizes low‐frequency (theta and/or alpha) oscillators and desynchronizes high‐frequency (beta) oscillators. These results provide novel insight into the cortical effects of cTBS and could be useful for exploring cTBS‐induced plasticity outside of the motor cortex.