Computational neuroethology: linking neurons, networks and behavior Mark E. Nelson Beckman Institute...
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Transcript of Computational neuroethology: linking neurons, networks and behavior Mark E. Nelson Beckman Institute...
Computational neuroethology:
linking neurons, networks and behavior
Mark E. Nelson
Beckman InstituteUniv. of Illinois, Urbana-Champaign
TALK OUTLINE
Multiscale modeling in computational neuroethologyModel system - weakly electric fishModeling strategies Level I: Behavior Level II: Sensory physics Level III: Single neurons Level IV: Local networks
Summary
MultiscaleOrganization of
theNervous System
Organism
Brain/CNS
Networks
Neurons
Synapses
Molecules
Brain maps
1 m
10 cm
1 mm
100 m
1 m
1 Å
1 cm
Churchland & Sejnowski 1988Delcomyn 1998
Neuroethology:Neural Basis of
Behavior
EnvironmentDelcomyn 1998
Sensors Effectors
Organism
SensoryProcessing
MotorControl
NeuralIntegration
Brain
Body
Neuroethology of Electrolocation
Big picture: What are the neural mechanisms and computational principles of active sensing?
Small picture: How do weakly electric fish capture prey? What computations take place in the CNS during prey capture behavior?
mech
an
o
MacIver, fromCarr et al., 1982
Electroreceptors ~15,000 tuberous electroreceptor organs1 nerve fiber per electroreceptor organ
up to 1000 spikes/s per nerve fiber
Ecology & Ethology of A. albifrons
inhabits tropical freshwater rivers and streams in South America
nocturnal; hunts at night for aquatic insect larvae and small crustaceans in turbid water
uses electric sense for prey detection, navigation, social interactions
ribbon fin propulsion – forward/reverse/hover
Rapid reversal marks putative time-of-detection
Velocity
Profile(N=116)
Acceleration
Profile(N=116)
Zero-crossingin acceleration
is used asdetection time
Neuroethology:Neural Basis of
Behavior
EnvironmentDelcomyn 1998
Sensors Effectors
Organism
SensoryProcessing
MotorControl
NeuralIntegration
Brain
Body
Voltage perturbation at skin :
Estimating Daphnia signal strength
waterprey
waterpreyfish ar
rE
/21
/133
electrical contrastprey volume
fish E-field at prey
distance from prey to receptor
THIS FORMULA CAN BE USED TO COMPUTE THE SIGNAL AT EVERY POINT ON THE BODY
SURFACE
mech
an
o
MacIver, fromCarr et al., 1982
Electroreceptors ~15,000 tuberous electroreceptor organs1 nerve fiber per electroreceptor organ
Probability coding(P-type) afferent spike trains
00010101100101010011001010000101001010
Phead = 0.333
Phead = 0.337 Phead =
0.333
Compartmental Modeling
)()()( 43LmLKmKNamNaion EVgEVngEVhmgI
mVmVdt
dmmm )()1)((
hVhVdt
dhhh )()1)((
nVnVdt
dnnn )()1)((
Hodgkin-Huxley Model forvoltage-dependent
conductances
Spatiotemporal processing in 3 parallel ELL maps
Primary Electrosensor
y Afferents
Centromedial map Space: small RFs Time: low-pass
Centrolateral map Space: med. RFs Time: band-pass
Lateral map Space: large RFs Time: high-pass
tem
pora
l
inte
grat
ion
bothspatial
integration
Neuroethology:Neural Basis of
Behavior
EnvironmentDelcomyn 1998
Sensors Effectors
Organism
SensoryProcessing
MotorControl
NeuralIntegration
Brain
Body