responses to stimuli in larval zebrafish Alix Lacoste Methods in Computational Neuroscience Final Project Presentation August 2011 Arousal in larval zebrafish is correlated with rest ID: 582121
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Slide1
Predicting
responses to stimuli in larval zebrafish
Alix Lacoste
Methods in Computational Neuroscience
Final
Project
Presentation,
August 2011
Slide2
Arousal in larval zebrafish is correlated with rest
Fish are more active during the day than at night
The response to their environment varies with stimulus strength and circadian time
Probability of Response
Increasing
stimulus (tap)
strength
d
uring the day
at night
Stimulus
Stimulus
Prober et al. 2006Slide3
Analyzing responses to stimuli
Predicting response to stimuli using the history of movement
Can movement
before the
stimulus (tap)
predict whether the fish will respond to the tap
? Hypothesis: If fish have not moved recently, they are less likely to respond to the tap
Classifying fish by response types
Are there different types of responses to the stimulus?
Hypothesis: Slide4
1. Movement
before a tap influences
response
probability
Average trace before a tap, conditional on the
response
or
lack of response
Mean Amplitude of
movement(Δ
pixel)Time before the tap (sec)
Half of the tap trial data = training set
Other half of the tap trial data =
test set
Projection onto trace followed by
response
Projection onto trace
not
followed by responseSlide5
Movement prior to a tap can predict
whether the fish responds: example
Projection of test movement vector onto the mean training vector that is followed by
no response
Projection of test movement vector onto the mean training vector that is followed by a
response
y
x
y
x
y
=
x
=Slide6
Movement prior to a tap can predict
whether the fish
responds: more examples
Responses and non responses are correctly separated with this analysis
In cases where there was no movement before the tap, it is not possible to predict whether the fish will move in response to the tapSlide7
2. Response
clustering
PCA
Eigenvalues
Main Eigenvectors
Movement amplitude
Time
relative to the stimulus (tap)Slide8
Response clustering
Average response waveforms
Principal component analysis finds the very large responses (group 1). These responses are likely initiated via a distinct neural circuit (Mauthner cell escape system?)
Projection of post-tap movements
onto main eigenvectors
Group 1
Group 2Slide9
Conclusions
We
can predict
whether
a fish will respond to a stimulus
by analyzing its
movement prior to the stimulus
Next steps: Use more sophisticated statistics of prior movement to better predict responses
Response movement traces can be clustered using principal component analysis and suggest that distinct neural circuits are involved in producing responses
Next steps: a) Use movement statistics to predict response type. b) Find neural correlates of different response types. Slide10
Thank you!
David Schoppik
in Alex
Schier’s
lab
Hubert and
EladMichael Berry