3t magnetom trio tim

MEG data were recorded continuously (600 Hz sampling rate, DC-100 Hz low-pass filter, third-order spatial gradient noise cancellation), using a 151 channel CTF system (MISL Ltd., Canada) in a magnetically shielded room located at the Hospital for Sick Children, Toronto. Head position within the MEG dewar was determined by the use of three localization coils placed at the nasion and left and right pre-auricular points and measured before and after each run. Conditions with head movements greater than 5 mm are systematically re-run; however, this was not necessary in this study. To co-register MEG data with anatomical images, the 3 localization coils were replaced with MRI-visible contrast markers, and a structural magnetic resonance image (MRI) was obtained from each participant. These images were acquired using T1-weighted MRI scans covering the whole brain (3D MPRAGE (Sag; FOV = 192×240×256 mm; 1 mm iso voxels; TR/TE/TI/FA = 2300/2.96/900/9, GRAPPA = 2) on a 3T MAGNETOM Tim Trio (Siemens AG, Erlangen, Germany) with a 12-channel head coil.

High-resolution T1-weighted (224 slices, 0.8 mm³ isotropic resolution, TE = 3.74 ms, TR = 2,400 ms, TI = 1,000 ms, flip angle = 8 degrees), T2-weighted (224 slices, 0.8 mm³ isotropic resolution, TE = 479 ms, TR = 3,200 ms) both with 0.8 isotropic resolution, and resting-state BOLD data were collected on a Siemens 3T Magnetom Tim Trio with a 12-channel head coil (Gordon et al., 2017 (link)). Functional scans were collected with a gradient-echo EPI sequence, isotropic 4-mm³ voxels, TE of 27 ms, and TR of 2,200 ms (Gordon et al., 2017 (link)). The MSC dataset is considered a deep (precision) dataset with 5 hours of resting-state data per subject in 30-min blocks over 10 separate sessions (Gordon et al., 2017 (link)).

Functional and structural images were collected using a Siemens 3T Magnetom TIM Trio. A high resolution anatomical image covering the entire brain was acquired using an axial 3D MPRAGE sequence, parallel to the AC-PC line (TE/TI/TR = 3.29 ms/900 ms/2200 ms, flip angle = 9°, 1 mm³ voxel, 192 axial slices, matrix size = 256 × 192). Functional images were acquired while participants completed a card guessing task (described below) using a gradient echo EPI sequence that covered 37 axial (AC/PC aligned) slices encompassing the cerebrum and most of the cerebellum (TR/TE = 2000/28 ms, FOV = 200 × 200, matrix = 64 × 64, flip angle = 90°; 3.1 mm³, 0 mm gap).

Five minutes of resting-state MEG data were acquired in supine position using a CTF 151-channel system (CTF-MISL, Coquitlam, Canada) positioned within a magnetically shielded room (MSR). Participants were instructed to fixate on a centrally positioned gray cross (+) within a circle on a black background, back projected onto a screen inside the MSR. Data were acquired at a sampling frequency of 600 Hz operating in third-order synthetic gradiometry configuration. Prior to acquisition, participants were fitted with three head position indicator coils, located at the nasion and left and right preauricular points. These coils were tracked continuously, enabling a moment-to-moment measurement of head motion. The location of these coils was recorded, and MRI-visible markers positioned at these locations to coregister between MEG and MRI data.
An anatomical T1-weighted image was also acquired for all participants using a 3T Magnetom Tim Trio (Siemens AG, Erlangen, Germany) MRI system using a 12-channel head coil running an MPRAGE pulse sequence (TR = 2,300 ms; TE = 2.9 ms; flip angle = 9°; field of view = 240 × 256 × 192 mm; slice thickness 1 mm³).