Discovery 3t mri scanner

We used a General Electric Discovery 3 T MRI scanner with an 8-channel head coil. Echo-planar images were acquired using the following settings: flip angle 75, TE 30, TR 2.5 s, field of view 28.8 cm, slice thickness 3 mm, 49 slices, interleaved bottom → up. This sequence was chosen to optimise imaging of the amygdala and did not give whole-brain coverage. As described in Ref.^{19 (link)}, participants with less than 90% amygdala coverage were not included in this sample. The lowest slice was placed at the superior border of the pons. Five dummy volumes were run before recording began. We used higher-order shimming, where the volume of interest was restricted to a manually defined ellipsoid covering approximately the cerebrum. T1-weighted anatomical scans were acquired with a sagittal BRAVO sequence, field of view 24 cm, slice thickness 1 mm, flip angle 11, inversion time 450, interleaved bottom → up.

The MRI data of the Sleepy Brain Project were acquired using a General Electric Discovery 3T MRI scanner. T1 structural images were scanned using a sagittal brain volume (BRAVO) sequence with the following values: repetition time (TR) = 6.4 s, echo time (TE) = 2.8 s, flip angle = 11°, 1 × 0.47 × 0.47 mm³ voxel size, 24-cm field of view, 1-mm slice thickness, and 3.58 min of acquisition time. Meanwhile, echo-planar images were acquired using the following settings: flip angle = 75°, TE = 30 ms, TR = 2.5 s, field of view = 28.8 cm, slice thickness = 3 mm, 2.25 × 2.25 × 3 mm³ voxel size, 49 slices, 192 scans, and a total duration of 8 min (Nilsonne et al., 2017 (link); Tamm et al., 2017 (link)).

We used a General Electric Discovery 3 T MRI scanner. Echo-planar images were acquired using the following settings: flip angle 75, TE 30, TR 2.5 s, field of view 28.8 cm, slice thickness 3 mm, 49 slices, interleaved bottom → up. T1-weighted anatomical scans were acquired with a sagittal BRAVO sequence, field of view 24 cm, slice thickness 1 mm, interleaved bottom → up.