2 research outputs found
Noise Characterization, Modeling, and Reduction for In Vivo Neural Recording
Studying signal and noise properties of recorded neural data is critical in developing more efficient algorithms to recover the encoded information. Important
issues exist in this research including the variant spectrum spans of neural spikes that make it difficult to choose a globally optimal bandpass filter. Also, multiple
sources produce aggregated noise that deviates from the conventional white Gaussian noise. In this work, the spectrum variability of spikes is addressed, based on
which the concept of adaptive bandpass filter that fits the spectrum of individual spikes is proposed. Multiple noise sources have been studied through analytical
models as well as empirical measurements. The dominant noise source is identified as neuron noise followed by interface noise of the electrode. This suggests
that major efforts to reduce noise from electronics are not well spent. The measured noise from in vivo experiments shows a family of 1/f^x spectrum that can be reduced using noise shaping techniques. In summary, the methods of adaptive bandpass filtering and noise shaping together result in several dB signal-to-noise ratio (SNR) enhancement
Spike Feature Extraction Using Informative Samples
This paper presents a new spike feature extraction algorithm that targets real-time spike sorting and facilitates miniaturized microchip implementation. The proposed algorithm has been evaluated on synthesized waveforms and experimentally recorded sequences. When compared with many spike sorting approaches our algorithm demonstrates improved speed, accuracy and allows unsupervised execution. A preliminary hardware implementation has been realized using an integrated microchip interfaced with a personal computer.