Design of advanced neuroscience platform.

This paper presents the design of versatile platform for advanced neuroscience on the high-level brain functions and neural prostheses. The platform enables researchers to record and stimulate brain activities of multiple free behaving animals wirelessly. The platform consists of three major functional blocks of neural interface, wireless communication system, and neural signal processing software, which of each has fundamental challenges to be overcome. Ultra wideband communication system makes it possible to transmit a large amount of data produced by high-density microelectrode wirelessly and miniaturize the entire system so that it can be implanted or carried by animals. Multiple access capability is achieved by a sophisticated communication protocol optimized for biomedical applications. Noise is one of the most important factors affecting the design of the neural interface and neural signal processing technique to reduce the noise is presented. Prototype chips were fabricated to verify the feasibility of the platform and test results are shown as well.

A 128-channel 6 mW wireless neural recording IC with spike feature extraction and UWB transmitter.

This paper reports a 128-channel neural recording integrated circuit (IC) with on-the-fly spike feature extraction and wireless telemetry. The chip consists of eight 16-channel front-end recording blocks, spike detection and feature extraction digital signal processor (DSP), ultra wideband (UWB) transmitter, and on-chip bias generators. Each recording channel has amplifiers with programmable gain and bandwidth to accommodate different types of biological signals. An analog-to-digital converter (ADC) shared by 16 amplifiers through time-multiplexing results in a balanced trade-off between the power consumption and chip area. A nonlinear energy operator (NEO) based spike detector is implemented for identifying spikes, which are further processed by a digital frequency-shaping filter. The computationally efficient spike detection and feature extraction algorithms attribute to an auspicious DSP implementation on-chip. UWB telemetry is designed to wirelessly transfer raw data from 128 recording channels at a data rate of 90 Mbit/s. The chip is realized in 0.35 mum complementary metal-oxide-semiconductor (CMOS) process with an area of 8.8 x 7.2 mm(2) and consumes 6 mW by employing a sequential turn-on architecture that selectively powers off idle analog circuit blocks. The chip has been tested for electrical specifications and verified in an ex vivo biological environment.