Minimally Invasive, Wireless Neural Interfaces and Future Directions in Implantable Electronics

Clinically viable and minimally invasive neural interfaces stand to revolutionize disease care for patients of neurological conditions. For example, recent research in Brain Machine Interfaces (BMIs) has shown success in using electronic signals from the motor cortex of the brain to control artificial limbs, providing hope for patients with spinal cord injuries. Substantial improvements in neural implant longevity are needed to transition BMI systems from research labs to clinical practice. While action potential (AP) recording through penetrating electrode arrays offers the highest spatial resolution, it comes at the price of tissue scarring, resulting in signal degradation over the course of several months. Electrocorticography (ECoG) is an electrophysiological technique where electrical potentials are recorded from the surface of the cerebral cortex, reducing cortical scarring. However, today's clinical ECoG implants are large, have low spatial resolution and offer only wired operation.

To enable chronic and stable neural recording, we have developed a miniaturized, wireless ECoG microsystem. Wireless powering and readout are combined with a microfabricated antenna and electrode grid that has >10x higher electrode density than clinical ECoG arrays, providing spatial resolution approaching today's penetrating electrodes. Area and power reduction techniques in the baseband and wireless subsystem result in over 10x IC area reduction with a simultaneous 3x improvement in power efficiency over state-of-the-art, enabling a minimally invasive platform for 64-channel recording. The low power consumption of the IC, together with the antenna integration strategy enables remote powering at 3x below established safety limits. Wireless operation allows surgical site closure, greatly reducing infection risk, while the small size and flexibility of the implant minimize the foreign body response. The improved implant safety and longevity give wireless ECoG excellent prospects to become the technology of choice for clinically relevant BMIs in the foreseeable future.

Speaker: Rikki Muller, Cortera Neurotechnologies