Inter-hemispheric alpha power (in μV2/Hz). Group mean (± S.E.) log transformed inter-hemispheric alpha power asymmetry values (y-axis) for seven site pairs (x-axis) in PD patients and normal controls during emotional stimuli. More negative numbers indicate less delta power. Lower numbers (i.e., more negative) are associated with increased activation . The significant site pair (p < 0.05) differences between the groups were marked as *.