Unleashing potential: Transcranial direct current stimulation over the right posterior parietal cortex improves change detection in low-performing individuals
Journal
Journal of Neuroscience
Journal Volume
32
Journal Issue
31
Start Page
10554
End Page
10561
Date Issued
2012-08-01
Author(s)
Hsu, Tzu-Yu
Chang, Chi-Fu
Tzeng, Ovid J.L.
Hung, Daisy L.
Muggleton, Neil G.
Walsh, Vincent
Liang, Wei-Kuang
Cheng, Shih-Kuen
Juan, Chi-Hung
DOI
10.1523/JNEUROSCI.0362-12.2012
Abstract
The limits of human visual short-term memory (VSTM) have been well documented, and recent neuroscientific studies suggest that VSTM performance is associated with activity in the posterior parietal cortex. Here we show that artificially elevating parietal activity via positively charged electric current through the skull can rapidly and effortlessly improve people's VSTM performance. This artificial improvement, however, comes withan interesting twist: itinteracts with people's natural VSTM capability such that low performers who tend to remember less information benefitted from the stimulation, whereas high performers did not. This behavioral dichotomy is explained by event-related potentials around the parietal regions: lowper formers showed increasedwaveformsinN2pcandcontralateral delay activity (CDA), which implies improvement in attention deployment and memory access in the current paradigm, respectively. Interestingly, these components are found during the presentation of the test array instead of the retention interval, from the parietal sites ipsilateral to the target location, thus suggesting that transcranial direct current stimulation (tDCS) was mainly improving one's ability to suppress no-change distractors located on the irrelevant side of the display during the comparison stage. The high performers, however, did not benefit from tDCS as they showed equally large waveforms in N2pc and CDA, or SPCN (sustained parietal contralateral negativity), before and after the stimulation such that electrical stimulation could not help any further, which also accurately accounts for our behavioral observations. Together, these results suggest that thereis indeed a fixed upper limit inVSTM, but the low performers can benefit from neurostimulation to reach that maximum via enhanced comparison processes, and such behavioral improvement can be directly quantified and visualized by the magnitude of its associated electrophysiological waveforms.
Subjects
Analysis of Variance
Biophysics
Electric Stimulation
Electroencephalography
Evoked Potentials
Female
Functional Laterality
Humans
Male
Memory
Short-Term
Motor Cortex
Parietal Lobe
Photic Stimulation
Reaction Time
Signal Detection
Psychological
Visual Perception
Young Adult
Type
journal article