Totally Implantable Bidirectional Neural Prostheses: A Flexible Platform for Innovation in Neuromodulation

Abstract

Implantable neural prostheses are in widespread use for treating a variety of brain disorders. Until recently, most implantable brain devices have been unidirectional, either delivering neurostimulation without brain sensing, or sensing brain activity to drive external effectors without a stimulation component. Further, many neural interfaces that incorporate a sensing function have relied on hardwired connections, such that subjects are tethered to external computers and cannot move freely. A new generation of neural prostheses has become available, that are both bidirectional (stimulate as well as record brain activity) and totally implantable (no externalized connections). These devices provide an opportunity for discovering the circuit basis for neuropsychiatric disorders, and to prototype personalized neuromodulation therapies that selectively interrupt neural activity underlying specific signs and symptoms.

Keywords: bidirectional interface; brain sensing; brain-computer interface; deep brain stimulation; electrocorticography; local field potential; neural prostheses; oscillatory brain activity.

Figure 1

Illustration of a totally implanted bidirectional neural interface designed for chronic multisite recording in humans, as well as therapeutic neurostimulation. Quadripolar electrode arrays are implanted in the subthalamic nucleus and over motor cortex (enlarged view in inset), and attached to Activa PC+S (Medtronic Inc.) implanted over the pectoralis muscle. Data are non-invasively downloaded to an external tablet computer by radiotelemetry. The device is used to characterize networks related to abnormal movement in Parkinson's disease (Swann et al., 2016) and to prototype control algorithms for closed loop stimulation (Swann et al., 2018). This art, by UCSF medical illustrator Ken Probst, is also published in Swann et al. (Swann et al., 2017), with permission.