A prototype multi-electrode stimulation and recording probe for deep-brain stimulation, unveiled by IMEC at this week’s Design, Automation & Test in Europe (DATE) conference, opens up possibilities for more effective stimulation with less side effects. Other potential benefits include reduced energy consumption due to focusing the stimulation current on the desired brain target, and closed-loop control adapting the stimulation based on the recorded effect.
Brain implants for electrical stimulation of specified brain areas are used as a last-resort therapy for Parkinson’s disease, obsessive-compulsive disorder, and other brain ailments. Today’s deep-brain stimulation probes use millimeter-size electrodes. They stimulate, in a highly unfocused manner, a large area of the brain and create significant unwanted side effects.
IMEC’s design and modeling strategy consists of multiple electrodes, enabling simultaneous stimulation and recording. By employing this strategy, the designers created prototype probes with electrodes measuring 10 microns, and various electrode topologies.
The strategy relies on finite-element modeling of the electrical field distribution around the brain probe, accomplished with multi-physics simulation software COSMOL 3.4 and 3.5. The probe’s mechanical properties during surgical insertion could be investigated with the tools, too. Results show that adapting the penetration depth and field asymmetry makes it possible to steer the electrical field around the probe.
“To have a more precise stimulation and recording, we need electrodes that are as small as individual brain cells (neurons),” says Wolfgang Eberle, senior scientist and project manager at IMEC’s bioelectronics research group. “Such small electrodes can be made with semiconductor process technology, appropriate design tools, and advanced electronic signal processing.”