Integration of functional diffuse correlation spectroscopy and electroencephalography for measuring task-triggered brain activation in infants

Abstract

INTRODUCTION: The integration of functional diffuse correlation spectroscopy (fDCS) and the electroencephalography (EEG) allows us to examine the metabolic and electrophysiological aspects of cortical activity. Here we have tested the feasibility of measuring task-triggered neuronal responses in infants using hybrid fDCS-EEG. METHOD: Fortysix healthy 4-month-old infants (mean age=4.44 ± 0.55 months, 23 females) were enrolled. A 16-channel fDCS device and 128-sensors Geodesic (EGI, USA) system were used simultaneously. Stimuli used include 12-Hz flickering checkerboard, attention getters (AT) with looming face/toy, and baseline stimuli of moving clouds. For fDCS, the baseline (T0) was defined as 4 seconds before the onset of the AT, while time-1 (T1) and time-2 (T2) were identified as the 2-6s and 8-12s post AT. Data processing and statistical analysis were performed in MATLAB. RESULTS: For fDCS, the ANOVA analysis revealed significant interactions between time windows and sessions (F(1, 25) = 4.76, p = .04) and significant main effect of time window (F (1, 25) = 30.98, p <.001). Significant increase of relative changes of cerebral blood flow (rCBF) was found in T2 compared to T1 during the CK session but not in the SH session. For EEG measurements, we also observed a significant increase of time-locked VEP between 200-600 ms towards checkerboard stimuli in the occipital regions (p <.05 after FDR correction). CONCLUSION: Infants at 4 months exhibit increased CBF and VEP in response to checkerboard stimuli in the occipital regions. fDCS is feasible to use, independently or hybridized with EEG, to investigate task-evoked responses and cognitive processing in healthy developing infants.