MRI Sequence Information

All data were acquired on a Siemens MAGNETOM Prisma 3T scanner (software: syngo MR XA30) at the University of Oregon, using a 64-channel head/neck coil (HeadNeck_64).

Structural Data

T1-weighted (MPRAGE)

Parameter	Value
Protocol	ABCD_T1w_MPR_vNav
Sequence	3D GR/IR (tfl_mgh_epinav_ABCD)
TR	2500 ms
TE	2.9 ms
TI	1070 ms
Flip angle	8°
Voxel size	1.0 mm isotropic
Matrix	256 × 256 × 176
Acceleration	GRAPPA 2×
Sessions	ses-01, ses-28, ses-30

T2-weighted (SPACE)

Parameter	Value
Protocol	ABCD_T2w_SPC_vNav
Sequence	3D SE (space_mgh_epinav_ABCD)
TR	3200 ms
TE	565 ms
Flip angle	120° (variable)
Voxel size	1.0 mm isotropic
Matrix	256 × 256 × 176
Acceleration	GRAPPA 2×
Echo train length	190
Sessions	ses-01

T2-weighted oblique coronal

Parameter	Value
Protocol	T2_coronal_1.8
Sequence	2D TSE
TR	11250 ms
TE	84 ms
Flip angle	150°
Voxel size	~0.35 × 0.35 × 1.8 mm (512 × 512 in-plane)
Averages	2
Acceleration	GRAPPA 2×
Orientation	Oblique coronal (hippocampal long axis)
Sessions	ses-01

Diffusion Data

Parameter	Value
Protocol	cmrr_diff_3shell
Sequence	2D EPI (cmrr_mbep2d_diff)
TR	3000 ms
TE	70 ms
Flip angle	90°
Voxel size	1.8 mm isotropic
Matrix	116 × 116
Multiband factor	3
Acceleration	GRAPPA 2×
Partial Fourier	6/8
Diffusion scheme	Monopolar, 3-shell
Phase encoding dirs	AP, PA, LR, RL
Total readout time	42.0 ms
Sessions	ses-01, ses-28

Functional Data

BOLD (all functional tasks)

Parameter	Value
Protocol	Resting_baseline / task-specific
Sequence	2D EPI (cmrr_mbep2d_bold)
TR	1500 ms
TE	29 ms
Flip angle	90°
Voxel size	1.7 mm isotropic
Matrix	124 × 124
Slices	69 (23 per MB group × 3)
Multiband factor	3
Acceleration	GRAPPA 2×
Phase encoding	AP (j−)
Total readout time	36.3 ms
Effective echo spacing	0.295 ms

All functional tasks use identical acquisition parameters. Task-specific protocol names vary but the underlying sequence is the same.

Fieldmaps

Spin-echo EPI (for distortion correction)

Parameter	Value
Protocol	se_epi_ap / se_epi_pa
Sequence	2D SE-EPI (cmrr_mbep2d_se)
TR	6500 ms
TE	40.6 ms
Flip angle	90°
Voxel size	1.7 mm isotropic
Matrix	124 × 124
Phase encoding dirs	AP and PA (paired)
Total readout time	36.3 ms
Effective echo spacing	0.295 ms
Sessions	All functional sessions (ses-02 through ses-30)

AP/PA pairs are acquired at the start of each functional session for TOPUP-based distortion correction.