title: A real-time spike classification method based on dynamic time warping for extracellular enteric neural recording with large waveform variability.
abstract: BACKGROUND
  Computationally efficient spike recognition methods are required for real-time analysis of extracellular neural recordings. The enteric nervous system (ENS) is important to human health but less well-understood with few appropriate spike recognition algorithms due to large waveform variability.
  
  
  METHODS
  Here we present a method based on dynamic time warping (DTW) with high tolerance to variability in time and magnitude. Adaptive temporal gridding for "fastDTW" in similarity calculation significantly reduces the computational cost. The automated threshold selection allows for real-time classification for extracellular recordings.
  
  
  RESULTS
  Our method is first evaluated on synthesized data at different noise levels, improving both classification accuracy and computational complexity over the conventional cross-correlation based template-matching method (CCTM) and PCA+k-means clustering without time warping. Our method is then applied to analyze the mouse enteric neural recording with mechanical and chemical stimuli. Successful classification of biphasic and monophasic spikes is achieved even when the spike variability is larger than millisecond in width and millivolt in magnitude.
  
  
  CONCLUSIONS
  In comparison with conventional template matching and clustering methods, the fastDTW method is computationally efficient with high tolerance to waveform variability.
  
  
  CONCLUSIONS
  We have developed an adaptive fastDTW algorithm for real-time spike classification of ENS recording with large waveform variability against colony motility, ambient changes and cellular heterogeneity.
authors.affiliation: School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA. Electronic address: yc923@cornell.edu.
authors.forename: Yingqiu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Rakhilin
authors.affiliation: School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Philip H
authors.initials: PH
authors.lastname: Gordon
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
authors.forename: Xiling
authors.initials: X
authors.lastname: Shen
authors.affiliation: School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Kan
mesh_terms: D000200:Action Potentials; D000465:Algorithms; D000818:Animals; D016000:Cluster Analysis; D008810:Mice, Inbred C57BL; D008839:Microelectrodes; D009130:Muscle, Smooth / Q000502:physiology; D009197:Myenteric Plexus / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D010812:Physical Stimulation; D025341:Principal Component Analysis; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D046509:Tissue Culture Techniques; D058067:Wavelet Analysis
keywords: Dynamic time warping; Enteric nervous system; Extracellular action potentials; FET sensors