Figure 2:

For a representative subject, scalp maps of quasi-dipolar components (dipolarity above 85%) extracted by applying ICA (ICA-Only) or PCA (PCA-Only) directly to the data, or by performing ICA after reducing the original data rank by PCA so as to retain at least 85% (PCA₈₅ICA, 4 ± 0.5 Median ± MAD PCs), 95% (PCA₉₅ICA, 8 ± 2.5 PCs) and 99% (PCA₉₉ICA, 21 ± 6 PCs) of data variance respectively. Components are sorted into identifiable non-brain Artifact and Brain ICs, separated by the vertical red dashed line. A dashed blue box highlights eye activity-related artifact ICs (vertical EOG and horizontal EOG ICs, respectively) in the PCA₉₅ICA, PCA₉₉ICA, and ICA-Only conditions.