MRI data acquisition
MR images were acquired at the Baltic Imaging Center (Center for Diagnostic Radiology and Neuroradiology, University Medicine Greifswald) on a 3-T Siemens verio scanner (SIEMENS MAGNETOM Verio syngo MR B17) using a 32-channel head coil. Resting-state fMRI scans were acquired using an echo-planar-imaging sequence (3 × 3 × 3 mm³ voxel size, repetition time (TR) = 2000 ms, echo time (TE) = 30 ms, flip angle = 90°, 34 slices, descending acquisition, field of view 192 × 192 mm², 176 volumes, TA = 6.00 min). Participants were instructed to keep their eyes closed, to not think of anything in particular, and to try not to fall asleep (whether participants fell asleep or not was assessed per self-report directly after the resting-state scan; no participant reported to have fallen asleep). High-resolution anatomical images were acquired using a three-dimensional T1- weighted magnetization prepared rapid gradient echo imaging (1 mm³ isotropic voxel, TR = 2300 ms, TE = 2.96 ms, inversion time = 900 ms, flip angle = 9°, 256 × 240 × 192 mm³ matrix). Further, a diffusion-weighted spin-echo echo-planar imaging sequence was acquired (1.8 × 1.8 × 2.0 mm³ voxel size, TR = 11100 ms, TE = 107 ms, 70 slices, 64 directions (