A custom microchip for multi-channel neural stimulation and recording

DESCRIPTION provided by applicant Electrical stimulation through extracellular electrodes is an important method of neuroscience research By injecting controlled amounts of charge into neural tissue the membrane potential of nearby nerve cells can be raised sufficiently to elicit action potentials or andquot spikesandquot If the resulting neural activity is then observed scientists can us the complementary tools of stimulation and recording to study the structure and function of neural networks in the brain In the past two decades advances in microfabrication have led to the development of multisite extracellular electrodes that can contact more than sites in a local region of a brain Several companies have commercialized various types of miniature multisite electrodes and these are now in widespread use in the neuroscience research community However the size and expense of traditional rack mounted instruments required to interface with a large number of electrode sites presents a significant bottleneck in the adoption of multi channel neural stimulation and recording Stimulator units currently cost more than $ per channel Neural signal amplifier units are similarly expensive and it can be difficult to coordinate stimulation and recording between these two separate units so that the electrical transients produced by stimulation pulses do not saturate the amplifiers and produce long andquot blind spotsandquot in the neural recordings In the past three years Intan Technologies has developed and commercialized a series of microchips that integrates all functions of neural signal acquisition low noise amplification programmable band pass filtering analog to digital conversion and electrode impedance measurement onto a single silicon chip that can process signals from up to extracellular electrodes at the cost of less than $ per channel These chips are currently used in more than countries worldwide and have been adopted by many third party instrumentation companies However these chips are not capable of delivering stimulation pulses and they are not directly compatible with traditional stimulator units Intan Technologies proposes to integrate all the sensitive electronics needed for both stimulation and recording onto a small inexpensive silicon microchip andquot StimAmpChipandquot that will replace traditional rack mounted stimulators and amplifiers The use of advanced microelectronics will reduce bulky and expensive stimulation and amplifier systems down to the size of a postage stamp By integrating stimulators and amplifiers on the same chip their actions may be precisely coordinated to minimize amplifier saturation after stimulation pulses and allow neural activity immediately following stimulation to be observed A combined stimulation recording chip could be mounted in close proximity to a multisite electrode reducing noise pickup size and weight The StimAmpChip will have the capability to deliver charge balanced current pulses of programmable amplitude and duration and will have sufficient sensitivity to monitor extracellular voltages in the microvolt range PUBLIC HEALTH RELEVANCE The proposed program seeks to develop a microchip to reduce the size and cost of electrically stimulating neural tissue and monitoring the resulting activity Integrating both stimulator and amplifier electronics onto a single silicon chip will facilitate the development of large scale neural interfaces for scientific and medical research