Two techniques of non-parametric change point detection are applied to two different neuroscience datasets. In the 鍖rst dataset, we show how the multivariate non-parametric change point detection can precisely estimate reaction times to input stimulation in the olfactory system using joint information of spike trains from several neurons. In the second example, we propose to analyze communication and sequence coding using change point formalism as a time segmentation of homogeneous pieces of information, revealing cues to elucidate directionality of the communication in electric 鍖sh. We are also sharing our software implementation Chapolins at GitHub.
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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
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
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
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
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