ID: 222489 Softening Multi-Electrode Arrays to Engage Cervical Spinal Cord Circuits

We have developed softening spinal cord stimulating leads for modulation of the cervical spinal cord in the rat. These devices use a softening polymer that allows them to be relatively stiff at room temperature, to aid with insertion into the epidural space, and become supple in the body, preventing injury to underlying cervical spinal cord. The devices are fabricated with photolithography, enabling them to be very thin (∼50 microns). Our previous work demonstrated that these devices can safely modulate the cervical spinal cord over months and help restore forelimb function in rats with spinal cord injury. Here we sought to optimize the pattern of electrodes to optimally engage afferents at the dorsal root entry zone. We printed arrays with electrodes of different sizes, positions, and orientations and tested their efficiency in provoking forelimb muscle responses in rats.