A Microelectrode/Microelectronic Hybrid Device for Brain Implantable Neuroprosthesis Applications

Abstract

We have designed, fabricated, and characterized a microminiaturized "neuroport" for brain implantable neuroprosthesis applications, using an analog CMOS integrated circuit and a silicon based microelectrode array. An ultra-low power, low-noise CMOS preamplifier array with integral multiplexing was designed to accommodate stringent thermal and electrophysiological requirements for implantation in the brain, and a hybrid integration approach was developed to fabricate a functional microminiaturized neuroprobe device. Measurements showed that our fully scalable 16-channel CMOS amplifier chip had an average gain of 44 dB, bandwidth from 10 Hz to 7.3 kHz, and an equivalent input noise of approximately 9 microVrms with an average power consumption per preamplifier of 52 microW, which is consistent with simulation results. As a proof-of-concept demonstration, we have measured local field potentials from thalamocortical brain slices of rats, showing oscillatory behavior with an amplitude about 0.5 mV and a period ranging 80-120 ms. The results suggest that the hybrid integrated neuroport can form a prime platform for the development of a next level microminiaturized neural interface to the brain in a single implantable unit.

Applications of multi-variate analysis of variance (MANOVA) to multi-electrode array electrophysiology data

“…This technology has been applied to an expanding number of studies of neural activity, in both perceptual (Maynard et al, 1999) and cognitive (Johnson and Welsh, 2003) systems, and also in the development of implantable neuroprosthetic devices (Patterson et al, 2004;Warwick et al, 2004). The two main difficulties in achieving this step have been, firstly, the lack of appropriate tools to make simultaneous recordings from large numbers of individual neurones within a network and, secondly, the issue of analysing the resulting huge amount of high-density multi-variate data, in which significant effects may be sparse across the large sample of neurons.…”

Spatiotemporal dynamics of neocortical excitation and inhibition during human sleep

“…Recent technical improvements have allowed the nature of these dynamics in the human brain to be directly explored: Single-neuron activity in conjunction with local field potentials (LFPs) can be detected from the cerebral cortex and hippocampus in the course of intense monitoring of brain activity before surgical treatment of epileptic foci (6). Modern electrode systems provide the possibility of extracellular recordings of neuronal ensembles by using either microwires (7) or high-density microelectrode arrays (8,9). Prior efforts have demonstrated excellent recordings of single-neuron activity in human cerebral cortex (10-12).…”

Integrated wireless neural interface based on the Utah electrode array

“…System integration efforts to build fully or partially integrated, implantable neural interface devices have been pursued by several research teams (Aziz et al 2007;Martel et al 2001;Patterson et al 2004;Stieglitz et al 2000;Stieglitz et al 2005;Yao et al 2007). The techniques used to integrate the microelectrodes with electronics include using an intermediate substrate made of silicon (Yao et al 2007), flip-chip integration using conductive epoxy and thermal curing (Aziz et al 2007;Patterson et al 2004), or using thin film interconnections embedded in a flexible substrate (Martel et al 2001;Stieglitz et al 2000;Stieglitz et al 2005).…”