The control of movement can be studied

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The control of movement can be studied with the
countermanding (stop signal) task
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Inhibition function
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Race model can explain behavior
Stop Signal Reaction Time (SSRT) time needed to
cancel a previously planned movement
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Frontal Eye Field
(as part of a network!)
Controls when gaze shifts
Activation
0.0
0.1
0.2
Time from stimulus (sec)
Hanes, D.P. and J.D. Schall (1996) Neural control
of voluntary movement initiation. Science
274427-430.
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FEF
SC
movement neurons
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Mapping the race model onto neural processes
1 - The race model of countermanding performance
assumes that the GO and the STOP processes have
independent finish times (Logan Cowan, 1984).
2 Saccades are produced by a network of
interacting neurons.
Paradox How can a network of interacting
neurons produce behavior that looks like the
outcome of race between independent processes?
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Mapping the race model onto neural processes
Explore properties of simple network of GO and
STOP units.
Constrain by the properties of countermanding
behavior and by the form of activation of neurons
L.Boucher, G.D.Logan, T.J.Palmeri, J.D.Schall. An
interactive race model of countermanding
saccades. Program No. 72.10. 2003 Abstract
Viewer/Itinerary Planner.
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GO activation (GO growth rate STOP
inhibition) noise
STOP activation (STOP growth rate GO
inhibition) noise
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Independent Race Model
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Independent Race Model
Non-cancelled and no stop signal
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Interactive Race Model
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Interactive Race Model
Observed
Model Predictions
Non-cancelled and no stop signal
Cancelled and no stop signal