Table 1.

Descriptive statistics for resting state time series

Sub	Size before glob. sig. regr.		Size after glob. sig. regr.		Neg/Pos phase diff (s)	Corrs before glob. sig. regr.			Corrs after GSR	Difference in corr. values
	% Voxels with +ve PCC corr	% Voxels with −ve PCC corr	Task neg size (%)	Task pos size (%)		GS/Neg	GS/Pos	Neg/Pos	Neg/Pos
S1	66.56	0.02	7.01	4.53	2.6	0.77	0.65	0.22	−0.58		0.80
S2	82.67	0.09	4.93	3.80	0.6	0.86	0.84	0.51	−0.79	1.29
S3	25.79	0.00	11.05	3.10	0.8	0.64	0.69	0.07	−0.66	0.73
S4	24.93	0.19	10.01	11.91	6.4	0.62	0.69	−0.08	−0.87	0.79
S5	47.93	0.00	22.65	15.58	5.6	0.20	0.72	−0.51	−0.98	0.46
S6	77.92	0.00	13.82	3.34	5.6	0.85	0.36	0.07	−0.49	0.56
S7	95.77	0.03	7.41	8.31	2.2	0.86	0.73	0.38	−0.70	1.08
S8	95.14	0.00	6.05	0.66	0.2	0.88	0.55	0.18	−0.76	0.95
S9	87.93	0.06	7.32	5.26	1.6	0.89	0.85	0.55	−0.83	1.38
S10	74.03	0.06	4.89	0.52	0.8	0.82	0.93	0.62	−0.61	1.23
S11	51.25	0.59	13.76	3.66	9	0.72	0.35	−0.27	−0.73	0.51
S12	62.76	0.00	6.88	0.72	2	0.85	0.75	0.42	−0.59	1.02

Descriptive statistics for the size of regions (after thresholding at r = 0.35) that correlate both positively and negatively with the PCC before global signal regression are shown for each subject. Corresponding sizes after global signal regression (i.e., the size of the task negative and task positive regions, respectively) are also given. The phase between average time series from the task-negative and task-positive regions before global signal regression is reported. Correlations between these two time series and the global signal and between each other are shown (GS/Neg, GS/Pos and Neg/Pos respectively). The correlation between the task-negative and task-positive time series (Neg/Pos) after global signal regression along with the difference in correlation value that the global signal caused are also reported. Definitions: +ve = positive, −ve = negative, PCC = posterior cingulate cortex, GS = global signal, Neg = task-negative time series, Pos = task-positive time series, GSR = global signal regression.