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Non-parametric change point
detection for spike trains
Thiago S Mosqueiro
BioCircuits Institute
University of California San Diego
thmosqueiro.vandroiy.com
Conference on Information Sciences and Systems
Princeton (NJ), 03/15/2016
In collaboration with
Martin Strube-Bloss Rafael Tuma
Reynaldo Pinto Brian Smith Ramon Huerta
Take-home message
Reaction times of neural populations:
multivariate change-point detection
Electric 鍖sh communication:
change-point as a time-series segmentation
Complexity of Odorant Time Series
Vergara et al. 2013,
Sensors Actuators B 185 462
M. Trincavelli et al. 2009,
Sensors Actuators B 139 165
Picture by Kim S. Mosqueiro (Apr 2015)
Rodriguez-Lujan & J. Fonollosa et al. '2014,
Chem and Intell Lab Systems 30 123
Courtesy of M Trincavelli
Change point technique
The (single) change point problem can be stated as the
hypothesis testing below:
We are interested in two aspects:
How likely is H0 vs H1?
Estimate the transition point
Change point technique
Divergence:
Solution for the transition time:
Matteson and James 2014,
J American Statistical Association 109, 334345.
Mosqueiro & Maia 2012,
Phys Rev E 88 012712
Neural systems
We know some coding mechanisms
In insects, anatomy is
well documented
Mosqueiro & Huerta 2014, Current opinion in insect science
Main olfactory pathway
Mosqueiro, Strube-Bloss,
Smith & Huerta,
to appear
Proxy to reaction time
Strube-Bloss, et al. 2012,
PLOS One 7 e50322
Proxy to reaction time
Strube-Bloss, et al. 2012,
PLOS One 7 e50322
Using all spike trains
 To use all spike trains, we
get the 鍖rst 5 components
from PCA
 We then 鍖nd the change
point jointly
Neural reaction times
 No need for proxies and a single general concept
 Use the information of the whole spike train
 Yield much more precise results
 Could be applied to fMRI or EEGs, to jointly 鍖nd
change points within brain regions
 Can be performed on the 鍖y
Pulse-type electric 鍖sh
Forlim & Pinto 2014, PLOS One 9 e84885
Time series segmentation
Coarse-grained time scale
Fast time scale
 Change points are very close (most of time <2s apart)
 Average of 1.6 symbols / sec
 To turn it into a symbolic dynamic, we construct features:
(variance, avg slope, area under curve, interval duration)
Clustering of the segments
 Both 鍖sh showed similar symbols  cue on vocabulary
 Mutual Information drops after bootstrapping/surrogating
Segments showed 3 clusters:
Clustering of the segments
 Both 鍖sh showed similar symbols  cue on vocabulary
 Mutual Information drops after bootstrapping/surrogating
Segments showed 3 clusters:
Cues to Time-series segmentation
 No need for bins with 鍖xed size
 Coarser time scale may link to behavior
 Clustering symbols seems the same for three
different 鍖sh  is there a general vocabulary?
 Symbolic dynamics  is there a grammar?
 Current methods are VERY slow for such number of
change points
we have a new strategy coming soon
Free implementation
github.com/VandroiyLabs/chapolins
Parallel, multiple change points implementation 
in C for ef鍖cient of several algorithms 
with an API for Python
Logo courtesy of Andre MR Santos
Change Point Library for Non-parametric Statistics
Thanks, everyone, for
your attention

More Related Content

Non-parametric Change Point Detection for Spike Trains

  • 1. Non-parametric change point detection for spike trains Thiago S Mosqueiro BioCircuits Institute University of California San Diego thmosqueiro.vandroiy.com Conference on Information Sciences and Systems Princeton (NJ), 03/15/2016
  • 2. In collaboration with Martin Strube-Bloss Rafael Tuma Reynaldo Pinto Brian Smith Ramon Huerta
  • 3. Take-home message Reaction times of neural populations: multivariate change-point detection Electric 鍖sh communication: change-point as a time-series segmentation
  • 4. Complexity of Odorant Time Series Vergara et al. 2013, Sensors Actuators B 185 462 M. Trincavelli et al. 2009, Sensors Actuators B 139 165 Picture by Kim S. Mosqueiro (Apr 2015) Rodriguez-Lujan & J. Fonollosa et al. '2014, Chem and Intell Lab Systems 30 123 Courtesy of M Trincavelli
  • 5. Change point technique The (single) change point problem can be stated as the hypothesis testing below: We are interested in two aspects: How likely is H0 vs H1? Estimate the transition point
  • 6. Change point technique Divergence: Solution for the transition time: Matteson and James 2014, J American Statistical Association 109, 334345.
  • 7. Mosqueiro & Maia 2012, Phys Rev E 88 012712 Neural systems We know some coding mechanisms In insects, anatomy is well documented Mosqueiro & Huerta 2014, Current opinion in insect science
  • 8. Main olfactory pathway Mosqueiro, Strube-Bloss, Smith & Huerta, to appear
  • 9. Proxy to reaction time Strube-Bloss, et al. 2012, PLOS One 7 e50322
  • 10. Proxy to reaction time Strube-Bloss, et al. 2012, PLOS One 7 e50322
  • 11. Using all spike trains To use all spike trains, we get the 鍖rst 5 components from PCA We then 鍖nd the change point jointly
  • 12. Neural reaction times No need for proxies and a single general concept Use the information of the whole spike train Yield much more precise results Could be applied to fMRI or EEGs, to jointly 鍖nd change points within brain regions Can be performed on the 鍖y
  • 13. Pulse-type electric 鍖sh Forlim & Pinto 2014, PLOS One 9 e84885
  • 16. Fast time scale Change points are very close (most of time <2s apart) Average of 1.6 symbols / sec To turn it into a symbolic dynamic, we construct features: (variance, avg slope, area under curve, interval duration)
  • 17. Clustering of the segments Both 鍖sh showed similar symbols cue on vocabulary Mutual Information drops after bootstrapping/surrogating Segments showed 3 clusters:
  • 18. Clustering of the segments Both 鍖sh showed similar symbols cue on vocabulary Mutual Information drops after bootstrapping/surrogating Segments showed 3 clusters:
  • 19. Cues to Time-series segmentation No need for bins with 鍖xed size Coarser time scale may link to behavior Clustering symbols seems the same for three different 鍖sh is there a general vocabulary? Symbolic dynamics is there a grammar? Current methods are VERY slow for such number of change points we have a new strategy coming soon
  • 20. Free implementation github.com/VandroiyLabs/chapolins Parallel, multiple change points implementation in C for ef鍖cient of several algorithms with an API for Python Logo courtesy of Andre MR Santos Change Point Library for Non-parametric Statistics