A Bidirectional ASIC for Active Microchannel Neural Interfaces

Closed-loop neural prostheses have been widely used as a therapeutic strategy for a range of neurological, inflammatory, and cardiac disorders. Vagus nerve stimulation has shown promising results for the monitoring and treatment of post-operation symptoms of heart transplant recipients. A prime candidate for selective control of vagal fibres is the microchannel neural interface (MNI), which provides a suitable environment for neural growth and enables effective control of the neural activity in a bidirectional system. This paper presents the design and simulation of an ASIC in 180-nm high-voltage CMOS technology, capable of concurrent stimulation and neural recording with artifact reduction in a seven-channel MNI. The analog front-end amplifies action potentials with a gain of 40 dB, presenting a common-mode rejection ratio of 81 dB at 1 kHz and a noise efficiency factor of 5.13 over the 300 Hz to 5 kHz recording bandwidth. A 42-V-compliant stimulation module operates concurrently and independently across the seven channels

A Fully Implantable Opto-Electro Closed-Loop Neural Interface for Motor Neuron Disease Studies

This paper presents a fully implantable closed-loop device for use in freely moving rodents to investigate new treatments for motor neuron disease. The 0.18 µm CMOS integrated circuit comprises 4 stimulators, each featuring 16 channels for optical and electrical stimulation using arbitrary current waveforms at frequencies from 1.5 Hz to 50 kHz, and a bandwidth programmable front-end for neural recording. The implant uses a Qi wireless inductive link which can deliver >100 mW power at a maximum distance of 2 cm for a freely moving rodent. A backup rechargeable battery can support 10 mA continuous stimulation currents for 2.5 hours in the absence of an inductive power link. The implant is controlled by a graphic user interface with broad programmable parameters via a Bluetooth low energy bidirectional data telemetry link. The encapsulated implant is 40 mm × 20 mm × 10 mm. Measured results are presented showing the electrical performance of the electronics and the packaging method