Extended Data Fig. 2: Calibration of the BSI.
From: Walking naturally after spinal cord injury using a brain–spine interface
a, Post-operative localization of the cortical implants over the segmented brain of the participant that confirms the appropriate positioning of the 64-electrode grids over the activated regions of the primary motor cortex responding to attempted lower limb movements, as measured during functional magnetoencephalographic recordings. b, Post-operative localization of the paddle lead over the lumbosacral spinal cord to target lower limb muscles. c, Projection of linear regression weights associated with different lower limb movements (depicted on body schemes) onto the ___location of the implants, revealing the spatial segregation of movement-specific features. d, Electromyographic activity recorded from several lower limb muscles following a burst of epidural electrical stimulation using the more selective electrode configurations (schemes) and parameters (reported) translated into polar plots reporting the amplitude of muscle responses. e, Spatial distribution of linear regression weights associated with upper versus lower limb movements over the grid of 64 electrodes from each cortical implant. The firmware enabled the selection of 32 electrodes within the 64 electrodes of each implant. The red dots indicate the 32 selected electrodes from each implant based on the amount of identified movement-related information for each of the 64 electrodes. f, Spectral distribution of linear regression weights associated with upper versus lower limb movements, highlighting the importance of high sampling density in low frequencies compared to high frequencies. This ensemble of features guided the parameterization of the decoders. g, Detailed representation of the spatial and spectral repartition of weights associated with decoding of the 6 different lower limb joint movements.
