Figure 1.

Psilocybin infusion modifies the temporal variability of BOLD signal in a network comprising anterior cingulate cortex (ACC) and bilateral hippocampus. A) Maps of statistical significance for variance (σ ²) and total spectral power (TP) increases after psilocybin infusion. Results are shown overlaid separately into an anatomical MNI152 template, overlaid together and also rendered together into a three‐dimensional anatomical image. In all cases only clusters surviving a threshold of P < 0.05, Family Wise Error (FWE) cluster corrected (after passing an uncorrected threshold of P < 0.005) are shown. B) BOLD Variance time courses (obtained over a 1 min. sliding window) into the four regions of peak statistical significance defined in Table 1 for the psilocybin and the placebo infusion. C) Variance of the time course of intra‐hippocampal correlations (computed over a range of non‐overlapping window lengths) before and after psilocybin infusion. Results for placebo infusion are shown as insets (before and after in blue and red, respectively). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]