A miniature, implantable wireless neural stimulation system

Abstract

In this thesis, I present the design of a wireless neural stimulation system. The system consists of an external transmitter, controllable through a computer interface, and a miniature, implantable wireless receiver and stimulator. The implant is tailored for use in zebra finches - small birds weighing just 12-15g - as part of ongoing research into the neural mechanisms of sequence generation and learning. The implant, assembled on a miniature printed circuit board, contains a receiver coil, battery, electrodes, and a custom integrated circuit for data demodulation and neural stimulation. The chip, fabricated in a standard 0.5[mu]m CMOS process, is capable of delivering biphasic current pulses to 4 addressable electrode sites at 16 selectable current levels ranging from 100[mu]A to mA. Additionally, the biphasic pulses may be inverted. The entire implant weighs less than 1.5g and occupies a footprint smaller than 1.5cm2. A miniaturized neural stimulator such as this one also has applications in neural prostheses for blindness, Parkinson's disease, and paralysis.