OPM brain spinal cord data (2/2)

This dataset contains concurrent brain and spinal cord recordings made with optically pumped magnetometers (OPMs), together with surface electromyography (EMG), acquired during rest and sustained voluntary hand contraction (abductor pollicis brevis, APB). Due to file size, data from 2 participants and pre-computed results files for regenerating the main paper figures without re-running the full pipeline are available in this repository; data from the remaining 7 participants, along with the meshes and lead fields, is available at 10.5281/zenodo.20824565. Code for preprocessing data and analysing brain–spinal cord–muscle functional connectivity is available at https://github.com/meaghanspedden/brainspine-connectivity. Pre-computed results files for regenerating the main paper figures without re-running the full pipeline are available in the forGeneratingFigures/ folder. Experimental task Participants lay supine in a magnetically shielded room (MSR) wearing a custom 3D-printed scanner-cast. They performed alternating two-minute blocks of weak sustained right thumb abduction (~15% of maximal voluntary contraction) and rest, for five cycles. OPM recordings Brain and spinal cord magnetic fields were recorded simultaneously using 64 triaxial QuSpin Neuro-1 third-generation OPM sensors (QuSpin Inc., Louisville, CO, USA), mounted in a custom scanner-cast covering the scalp, neck, chest, and back. The system has an intrinsic bandwidth of 0–135 Hz. Experiments were conducted in a 438 × 338 × 218 cm MSR (Magnetic Shields Ltd, UK). Data were acquired at 1500 Hz. EMG recordings Surface EMG was recorded from the right APB muscle at 1000 Hz using pairs of surface electrodes (Ambu Ltd, Denmark), with a reference electrode at the right wrist. Signals were amplified and digitised outside the MSR using a BrainAmp system (Brain Products, Germany) and synchronised to OPM data via TTL pulse. Forward models Spinal cord magnetic field forward modelling was performed using a Biot-Savart law approximation. Each source point was modelled as a current dipole oriented along three orthogonal axes along the centre line of the spinal cord, with the magnetic field at each sensor computed analytically from the sensor-source geometry. Notes Participant OP00212 has full anatomical co-registration, the remaining participants use the common reference anatomy. /├── Leadfields_meshes/│ ├── geometries_experimental_withbrain.mat # Spinal cord geometry for Biot Savart forward model│ ├── leadfield_experimental_bslaw_experimental.mat # Precomputed Biot Savart lead field│ └── T.mat # MNI-to-native transformation matrix│└── sub-XX/ # One folder per participant (XX = participant ID) └── ses-001/ ├── emg/ # Surface EMG data (right APB muscle) │ ├── *.vhdr # BrainVision header file │ ├── *.eeg # BrainVision binary data file │ └── *.vmrk # BrainVision marker file └── meg/ # OPM recordings ├── *.tsv # Sensor position files ├── *.lvm # Raw OPM data ├── *.dat # Preprocessed OPM data (SPM .dat file) └── *.mat # Preprocessed OPM data (SPM .mat file) Version 2 (June 2026): The Leadfields_meshes/ folder has been updated to use a Biot-Savart forward model replacing the BEM lead field provided in v1. Version 1 (original release): BEM-based lead fields.