Z-scores of the variance (<i>v</i>) and <i>r</i>₁ in the 4 subdivisions of the precuneus.

<p>Significant differences in the <b><i>v</i></b> values among the 4 regions were revealed by the paired <b><i>t</i></b>-test (<i>p</i>-values were corrected with Bonferroni’s method). In contrast, there was no significant difference in the <b><i>r</i></b><b>₁</b> values among the 4 regions. Sm, sensorimotor region; tz, transitional zone; cg, cognitive/associative regions; vs, visual region.</p

Z-scores of the variance (<i>v</i>) and <i>r</i>₁ in the 2 subdivisions of the PCC.

<p>Both values were significantly higher in the ventral PCC than in the dorsal PCC (p<0.0001, paired <b><i>t</i></b>-test).</p

High <b><i>r</i></b><b>₁</b> cortical regions: Brodmann’s area (BA); Z-score (Z, mean (SD)).

<p>High <b><i>r</i></b><b>₁</b> cortical regions: Brodmann’s area (BA); Z-score (Z, mean (SD)).</p

Effective sample size calculated with various <i>r</i>₁ and <i>r</i>₁’ values.

<p>The original sample size is 102. The effective sample size decreases as the autocorrelation coefficient decreases.</p

Effect of sample size correction.

<p>The top images show the distribution of the cross correlation coefficients (p<0.05, <b><i>t</i></b>-test for each paired voxels’ data) between the ventral PCC and the other brain voxels without sample size correction (i.e., <i>N</i> = 102). The bottom images show the distribution of the voxels with the cross correlation coefficients that are significantly different from zero (p<0.05). The effective sample size (<i>N</i>’) (see text) was calculated for each pair of voxels with their autocorrelation coefficients and each pair’s <i>N</i>’ was used to assess the significance of the cross-correlation coefficient. For this subject, ∼46% of voxels were revealed not to be significant after sample size correction.</p

Distribution of the <i>r</i>₁ values for the gray matter voxels in one subject.

<p>The value ranges from 0.3 to 0.7 though most of the data are between 0.5 and 0.6.</p

Relative locations of the seeds in the subdivisions of the precuneus and PCC shown with mean Z-score maps of <i>v</i> and <i>r</i>₁.

<p>The mean Z-score map for the variance (<b><i>v</i></b>) is shown in the middle and the map for <b><i>r</i></b><b>₁</b> is shown in the bottom of the figure. Note that the distribution pattern for <b><i>v</i></b> is different from that for <b><i>r</i></b><b>₁</b> especially in the precuneus and PCC. <b>a</b>: ventral PCC; <b>b</b>: dorsal PCC; <b>c</b>: visual precueal region; <b>d</b>: cognitive/associative precuneal region; <b>e</b>: transitional zone; <b>f</b>: sensorimotor precuneal region.</p

<i>r</i>₂ t-value map.

<p>The result of one-sample <b><i>t</i></b>-test is shown excluding non-significant voxels (p>0.05 with FDR corrected). The distribution pattern is similar to that for <b><i>r</i></b><b>₁</b> (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038131#pone-0038131-g004" target="_blank">Fig. 4</a>).</p

Autocorrelation function of BOLD signals for 306 s.

<p>The bottom graph shows the data for the lag range from −1 to 10, which is indicated by the bar in the middle graph. Note that the autocorrelation is not normalized.</p

Variance <i>t</i>-value map.

<p>The result of one-sample <b><i>t</i></b>-test is shown excluding non-significant voxels (p>0.05 with FDR corrected). High variance is seen in restricted cortical regions, such as the vmPFC, insula, PCC, calcarine sulcus, and lateral parietal lobes.</p