Towards a Distributed, Chronically-Implantable Neural Interface

Abstract

We present a platform technology encompassing a family of innovations that together aim to tackle key challenges with existing implantable brain machine interfaces. The ENGINI (Empowering Next Generation Implantable Neural Interfaces) platform utilizes a 3-tier network (external processor, cranial transponder, intracortical probes) to inductively couple power to, and communicate data from, a distributed array of freely-floating mm-scale probes. Novel features integrated into each probe include: (1) an array of niobium microwires for observing local field potentials (LFPs) along the cortical column; (2) ultra-low power instrumentation for signal acquisition and data reduction; (3) an autonomous, self-calibrating wireless transceiver for receiving power and transmitting data; and (4) a hermetically-sealed micropackage suitable for chronic use. We are additionally engineering a surgical tool, to facilitate manual and robot-assisted insertion, within a streamlined neurosurgical workflow. Ongoing work is focused on system integration and preclinical testing. I. INTRODUCTION Brain Machine Interfaces (BMIs) have a genuine opportunity to effect a transformative impact on both medical [1], [2] and non-medical [3] applications. More specifically, clinical translation can lead to the restoration of movement and communication in patient populations with tetraplegia, amylotrophic lateral sclerosis, locked-in-syndrome, and speech disturbances. Current translational efforts utilize implantable medical devices (IMDs), e.g. Medtronic PC+S [1], experimental neuroscience tools, e.g. Blackrock Neuroport [2], or engineer new devices leveraged on IMDs [4], [5]. A. Key Challenges The major technical challenges with state-of-the-art BMI technology are chronic reliability (device longevity, recording stability, calibration/training) and scalability (extending number of recording and/or stimulation sites). In tackling these, wireless capability is crucial, but brings on its own set of challenges (wireless transfer efficiency, data throughput).

jULIEs: extracellular probes for recordings and stimulation in the structurally and functionally intact mouse brain

“…Other advantages of modified microwires are their composite nature: metal cores are effectively fused with the glass ensheathing providing a robust, defect and delamination-free very low parasitic-capacitance insulation 34 . Polymer coated microwires 35 , microfabricated polymer electrodes [36][37][38] , carbon fibers 33,39 , multimodal pipettes 40 , syringe-injectable mesh electrodes 41,42 and niobium microwires 43 , amorphous SiC 44 and active-CMOS probes 45 are promising avenues for potentially low-damage neural recordings. Several approaches have been put forward to allow for their connectorization to standard readout electronics however at very large scale (above 10k) these still remain a challenge.…”

Biointegrated and Wirelessly Powered Implantable Brain Devices: A Review

“…So far, some of the most common forms of wireless power system for implantable neural devices are discussed and summarized in Table II. Apart from these, there are emerging technologies which combines multiple stimulation options and optofluidic channel [146], [147], uses innovative approach to achieve an ultra-miniaturized implant [148], introduces scalable and distributed wireless neural platform [149], [150], wireless optoelectronic photometer for dynamic mapping of the brain [151], simultaneous multichannel optogenetics stimulation and multichannel electrical recording system [152]. Fig.…”

Challenges in Scaling Down of Free-Floating Implantable Neural Interfaces to Millimeter Scale

“…The second system, ENGINI, in Fig. 10 depicts another powering scheme, which also utilizes inductive coupling for both links [97]. Its first tier includes an external primary coil that propagates energy transcutaneously to the secondary coils located above the skull, which are connected to the epidural coils below the skull through wires.…”