Title: The Complexity of Brain Signals Predicts Our Performance in Cognitive Control and health Status
Speaker: Prof. Wei-Kuang Liang
Assistant Professor
Institute of Cognitive Neuroscience
National Central University

Time: 2014/6/17 (Tuesday)
Talk: 14:00～16:00
Location: NCU S5-101 (中央大學科五館 101 教室)

Abstract:
The processes of cognitive control allow information processing and behavior to vary adaptively from moment to moment in the brain. It requires our brain to make a fast adaptation to an ever-changing environment. These processes happen fast, in a complex manner, and sometimes are difficult to capture with fMRI or mean electrophysiological brain signal alone. Therefore, an alternative measure that can reveal the efficiency of the neural mechanism across multiple timescales is needed for the investigation of these brain functions.
We employed a new approach to analyzing EEG signal: the multiscale entropy (MSE) to quantify the complexity (indicating adaptability and efficiency) of neural systems during the process of cognitive control. First, we applied MSE to investigate EEG complexity during the process of inhibitory control, both with and without transcranial direct current stimulation (tDCS) over the presupplementary motor area (preSMA). We found that the complexity of EEG signals was higher for successful than unsuccessful inhibition, and that anodal tDCS over preSMA increased the complexity of EEG signals along with its behaviorally facilitating effect (Liang et al., 2014, NeuroImage; Liang and Juan, 2013 JNSNE;). Second, we applied MSE to examine the effects of physical activity on visuo-spatial cognitive capacity in older adulthood. We observed that physically active elderly adults displayed greater MSE over the frontal lobe along with better visuo-spatial attention and working memory performance relative to their physically inactive counterparts (Wang et al., 2014, under revision).
Therefore, we propose that the MSE, both theoretically and pragmatically, is an elaborate index that can reveal the efficiency of the cognitive neural mechanism. Furthermore, we suggest that these MSE findings can serve as a theoretical basis for tDCS and exercise intervention, and can offer a novel direction to future studies for clinical conditions where deficits in cognitive control are implicated.