Real-time brain state-coupled network-targeted magnetic stimulation to enhance working memory

Working memory impairment is a common affliction in disorders such as Alzheimer’s disease, ADHD, and major depression, among others. Brain stimulation is a promising tool for modulating brain networks and improving cognitive performance. We applied non-invasive brain stimulation—using transcranial magnetic stimulation (TMS)—in a real-time brain state-dependent manner to frontal and parietal regions of the brain that are involved in working memory with the goal of memory enhancement in healthy subjects. Theta phase was used as a brain state marker while changes in working memory accuracy rate served as a primary outcome measure. This fully non-invasive protocol employs real-time analysis of electrophysiologic signals from the brain using EEG to trigger magnetic pulses at specific phases of the theta oscillation. We found that applying paired magnetic pulses during real-time theta oscillation brain state coupled stimulation  significantly enhances working memory accuracy compared to baseline. There was no significant change in accuracy using the brain state uncoupled protocol. Targeting the pathway specific to a memory network may maximize the cognitive enhancement potential of brain state-dependent cortical paired associative stimulation (cPAS) in healthy individuals and patients with Alzheimer’s disease, ADHD, depression, and other disorders affecting memory.

Project contributors: Blair Jovellar

Funding: European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ConnectToBrain, ERC synergy grant agreement No. 810377)