Transcranial direct current stimulation (tDCS) is a non-invasive stimulation method that can induce transient polarity-specific neuroplastic changes in cortical excitability lasting up to 1h post-stimulation. While excitability changes with stimulation over the primary motor cortex have been well documented, the functional effects of stimulation over premotor regions are less well understood. In the present experiment, we tested how cathodal and anodal tDCS applied over the region of the supplementary motor area (SMA) affected preparation and initiation of a voluntary movement. Participants performed a simple reaction time (RT) task requiring a targeted wrist-extension in response to a go-signal. In 20% of RT trials a startling acoustic stimulus (SAS) was presented 500 ms prior to the "go" signal in order to probe the state of motor preparation. Following the application of cathodal, anodal, or sham tDCS (separate days) over SMA for 10 min, participants performed blocks of RT trials at 10 min intervals. While sham stimulation did not affect RT or incidence of early release by the SAS, cathodal tDCS led to a significant slowing of RT that peaked 10 min after the end of stimulation and was associated with a marked decrease in the incidence of movement release by the SAS. In contrast, anodal tDCS resulted in faster RTs, but the incidence of release was unchanged. These results are consistent with the SMA playing a role in the pre-planning of movements and that modulating its activity with tDCS can lead to polarity-specific changes in motor behavior.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4857713 | PMC |
http://dx.doi.org/10.1016/j.bbr.2014.11.009 | DOI Listing |
J Alzheimers Dis
January 2025
School of Clinical Medicine, Qilu Medical University, Zibo, Shandong, China.
Background: Alzheimer's disease (AD) is a neurodegenerative disease. At present, there are currently no drugs that can cure AD.
Objective: A number of empirical studies have shown that transcranial direct current stimulation (tDCS) may be used to treat cognitive abnormalities in patients with AD.
Alzheimers Dement
December 2024
The Chinese University of Hong Kong, Hong Kong, Hong Kong, Hong Kong.
Background: To investigate the effects of 40 Hz high-definition transcranial alternating current stimulation (HD-tACS) on subjective sleep quality and domain-specific cognitive functions in mild neurocognitive disorders due to Alzheimer's disease (NCD-AD).
Method: This study was a double blind, sham-controlled randomized clinical trial. Ninety-nine mild NCD-AD patients were randomly assigned to receive a 4-week course treatment of either 40 Hz HD-tACS, HD transcranial direct current stimulation (HD-tDCS), or sham transcranial current stimulation (HD-tCS).
Alzheimers Dement
December 2024
Applied Medical Sciences, Misr University for Science and Technology, Cairo, Egypt.
Background: Gamma desynchronization is an early pathophysiological event in Alzheimer's disease with a disturbance in oscillation in the gamma frequency range 30-80 Hz. This disruption was found to be directly related to the disease progression and severity. Thus, the use of transcranial alternating current stimulation (tACS) possessed greater interest.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Hinda and Arthur Marcus Institute for Aging Research at Hebrew SeniorLife, Boston, MA, USA.
Background: Alzheimer's disease (AD) affects over 55 million people worldwide and is characterized by abnormal deposition of amyloid-β and tau in the brain causing neuronal damage and disrupting transmission within brain circuits. Episodic memory loss, executive deficits, and depression are common symptoms arising from altered function in spatially distinct brain circuits that greatly contribute to disability. Transcranial electrical stimulation (tES) can target these circuits and has shown promise to relieve specific symptoms.
View Article and Find Full Text PDFNeuroimage
January 2025
School of Computing, Tokyo Institute of Technology, Yokohama, Japan; ATR Brain Information Communication Research Laboratory Group, Kyoto, Japan. Electronic address:
Transcranial direct current stimulation (tDCS) is a potential method for improving verbal function by stimulating Broca's area. Previous studies have shown the effectiveness of using functional magnetic resonance imaging (fMRI) to optimize the stimulation site, but it is unclear whether similar optimization can be achieved using scalp electroencephalography (EEG). Here, we investigated whether tDCS targeting a brain area identified by EEG can improve verbalization performance during a picture-naming task.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!