Clinical Research Directory

Anodal tDCS Over Left PPC Enhances Visuospatial Attention and Alpha Power Among Young Adults

Background: Visuospatial attention enables individuals to detect and process relevant stimuli efficiently. The posterior parietal cortex (PPC), a core hub of the dorsal attention network, exerts top-down control over visual scanning and is closely linked to alpha-band oscillations (8-13 Hz), which index attentional allocation and inhibition of distractors. Transcranial direct current stimulation (tDCS) offers a noninvasive method to alter cortical excitability transiently, but evidence for its effects on PPC-mediated attention and alpha power remains mixed. Objective: This randomized, single-blind trial examined whether anodal tDCS over the left PPC modulates visuospatial attention and resting-state alpha power in young adults, and whether EEG changes predict behavioral performance. Method: Thirty-two healthy participants (18-40 years) were randomized to anodal (2 mA, 20 min; n=15) or sham (n=17) stimulation. Cancellation Test performance and resting-state EEG were assessed pre- and post-stimulation. EEG analyses focused on artifact-free alpha power; regression models probed associations between neural and behavioral changes.

Examining Lateralized Aspects of Motor Control Using Non-invasive Neural Stimulation

Motor adaptation and generalization are believed to occur via the integration of various forms of sensory feedback for a congruent representation of the body's position in space along with estimation of inertial properties of the limb segments for accurate specification of movement. Thus, motor adaptation is often studied within curated environments incorporating a "mis-match" between different sensory systems (i.e. a visual field shift via prism googles or a visuomotor rotation via virtual reality environment) and observing how motor plans change based on this mis-match. However, these adaptations are environment-specific and show little generalization outside of their restricted experimental setup. There remains a need for motor adaptation research that demonstrates motor learning that generalizes to other environments and movement types. This work could then inform physical and occupational therapy neurorehabilitation interventions targeted at addressing motor deficits.