Figure 1 : Principal component analysis (PCA) and delay estimation of auditory and visual evoked responses.

From: Age-related delay in visual and auditory evoked responses is mediated by white- and grey-matter differences

Figure 1

(a) Two-dimensional topographical MEG sensor plot of the first spatial component derived using PCA in the Passive task. Values represent the root mean square (RMS) of each pair of gradiometers. (b) Group Multiple Sparse Prior (MSP) source reconstruction based on the spatial component shown in a (cluser peak MNI coordinates: right HG=[+38, −22, +8], left=[−38, −26, +8]; right V2=[+14, −96, +20], left=[−14, −96, +20]; ES right=[+16, −74, +24], left=[−16, −74, +20]). (c) Heat-maps illustrating the mean time course for each participant from the first temporal component of the PCA. Data are smoothed in the y direction for visualization only (Gaussian width=5 subjects). (d) Group average time courses for each of three age groups (18–44, 45-65, 66–88 years). Because all of our analyses are based on principal components, the y axis of plots have arbitrary units.