L-Sort: On-Chip Spike Sorting With Efficient Median-of-Median Detection and Localization-Based Clustering

Spike sorting is a critical process for decoding large-scale neural activity from extracellular recordings. The advancement of neural probes facilitates the recording of a high number of neurons with an increase in channel counts, arising a higher data volume and challenging the current on-chip spik...

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Bibliographic Details
Main Authors: Yuntao Han, Yihan Pan, Xiongfei Jiang, Cristian Sestito, Shady Agwa, Themis Prodromakis, Shiwei Wang
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of Circuits and Systems
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Online Access:https://ieeexplore.ieee.org/document/11072521/
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Summary:Spike sorting is a critical process for decoding large-scale neural activity from extracellular recordings. The advancement of neural probes facilitates the recording of a high number of neurons with an increase in channel counts, arising a higher data volume and challenging the current on-chip spike sorters. This paper introduces L-Sort, a novel on-chip spike sorting solution featuring median-of-median spike detection and localization-based clustering. By combining the median-of-median approximation and the proposed incremental median calculation scheme, our detection module achieves a reduction in memory consumption. Moreover, the localization-based clustering utilizes geometric features instead of morphological features, thus eliminating the memory-consuming buffer for containing the spike waveform during feature extraction. Evaluation using Neuropixels datasets demonstrates that L-Sort achieves competitive sorting accuracy with reduced hardware resource consumption. Implementations on FPGA and ASIC (180 nm technology) demonstrate significant improvements in area and power efficiency compared to state-of-the-art designs while maintaining comparable accuracy. If normalized to 22 nm technology, our design can achieve roughly <inline-formula> <tex-math notation="LaTeX">$\times 10$ </tex-math></inline-formula> area and power efficiency with similar accuracy, compared with the state-of-the-art design evaluated with the same dataset. Therefore, L-Sort is a promising solution for real-time, high-channel-count neural processing in implantable devices.
ISSN:2644-1225