spike sorting based on dominant-sets clustering dimitrios a. adamos phd candidate school of biology,...
TRANSCRIPT
![Page 1: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/1.jpg)
Spike Sorting based on Dominant-Sets clustering
Dimitrios A. AdamosPhD Candidate School of Biology, Aristotle University
04/21/23Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
![Page 2: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/2.jpg)
What is spike sorting?
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Spike Sorting Algorithms
Buzsáki, G. (2004). Large-scale recording of neuronal ensembles. Nature Neuroscience
Spikes
Noise
![Page 3: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/3.jpg)
Spike sorting in a nutshell
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
![Page 4: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/4.jpg)
Spike sorting applications
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Linderman et al. (2008). Signal processing challenges for neural prostheses. IEEE Signal Processing Magazine
Hochberg et al. (2006). Neuronal ensemble control of prosthetic devices by a human with tetraplegia. Nature
BrainGate
![Page 5: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/5.jpg)
Spike sorting applications
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Wong et al. (2009). Functional localization and visualization of the STN from microelectrode recordings acquired during DBS surgery with unsupervised machine learning. J Neural Eng
Functional STN Targeting during DBS surgery
![Page 6: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/6.jpg)
Open problems in spike sorting #1
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Resolution of overlapping spikes
Adamos DA, Laskaris NA , Kosmidis EK and Theophilidis G.
NASS: An empirical approach to Spike Sorting with overlap
resolution based on a hybrid Noise-Assisted methodology
(2010) Journal of Neuroscience Methods Article in Press doi:10.1016/j.jneumeth.2010.04.018
![Page 7: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/7.jpg)
Open problems in spike sorting #2
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Goal of this study: Correct estimation of active neuronsChallenges: Noise & Sparsely firing
neuronsCommon clustering errors: Under-clustering & over-clustering
Under-clustering example
![Page 8: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/8.jpg)
Methods
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Combination of two methods from the graph-theoretic domain
#1 ISOMAPGraph-theoretic
feature extraction
#2 Dominant-setsGraph-theoretic
clustering
![Page 9: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/9.jpg)
Methods #1: Non-linear low-dimensional representation
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Manifold learning: Isometric Feature Mapping (ISOMAP)
![Page 10: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/10.jpg)
Methods #2: Graph-Theoretic Clustering
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Dominant-Sets clustering Internal criterion: all objects inside a cluster
should be highly similar to each other External criterion: all objects outside a cluster
should be highly dissimilar to the ones inside Similarity is represented by weights:
K-means Dominant-Sets
![Page 11: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/11.jpg)
Algorithm
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Replicator Dynamics approach
![Page 12: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/12.jpg)
Comparative evaluation
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
3 neurons (3 x 300 spikes) 150 random double-overlaps (3 x 50 spikes) 50 random triple-overlaps Variable SNR
![Page 13: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/13.jpg)
Low SNR example
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
2 firing neurons (2 x 300 spikes) ++ 1 sparse-firing neuron (30 spikes) + overlaps (150 spikes)
WaveClus
Neuron 1 Neuron 2 Sparse-firing neuron
Noise
Graph-Theoretic Spike
Sorting
Neuron 1 Neuron 2 Sparse-firing neuron
Overlaps
Overlaps
![Page 14: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/14.jpg)
Conclusions
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Problem: Estimating the number of active neurons
Methods Methods from the graph-theoretic domain Replicator dynamics approach
Results Semi-supervised spike-sorting approach with
relative ranking of groups High ranking: active neurons Medium ranking: overlapping and noisy spikes
that need further processing Low ranking: noise
![Page 15: Spike Sorting based on Dominant-Sets clustering Dimitrios A. Adamos PhD Candidate School of Biology, Aristotle University 5/19/2015Laboratory of Animal](https://reader035.vdocuments.net/reader035/viewer/2022070415/56649d0a5503460f949dc445/html5/thumbnails/15.jpg)
04/21/23
Laboratory of Animal Physiology, School of Biology, Aristotle University of Thessaloniki
Thank you