Analysis of a biologically realistic model for saccade-countermanding tasks

Kong-Fatt Wong, Philip Eckhoff, Philip Holmes, Jonathan Cohen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In saccade-countermanding tasks, fixation neurons in the frontal eye fields or superior colliculus have high activity during fixation period, sending inhibition to the (build-up) movement neurons. Upon fixation offset and a simultaneous presentation of a Go signal or target, the movement neurons, with response fields where the target lies, exhibit ramping activity. If this ramping activity reaches a certain threshold, a saccade will be made toward the target. However, when a Stop signal appears briefly after target onset, the reactivation of the fixation neurons may suppress the activity of the movement neurons before it reaches threshold, thus producing successful suppression of saccade. The time between onset of the Go and Stop signals is called the stop-signal delay, which is varied by the experimentalists.In this work, we construct a biologically realistic model of saccade-countermanding tasks. The model consists of a population of movement neurons and a population of fixation neurons. Using phase-plane analysis, we show, under certain sets of network parameters, that even if the stop signal occurs before the movement neuronal activity reaches threshold, a saccade can still subsequently occur. We further investigate how inhibitory control of saccades optimizes reward rate, and how this depends on the stop-signal delay, the probability of target presentation, and the probability of having a stop signal within a block of trials.
Original languageEnglish
Title of host publicationUnknown Host Publication
PublisherSociety for Neuroscience
Number of pages1
Publication statusPublished - 2007
EventSociety for Neuroscience 2007 - San Diego, CA, USA
Duration: 1 Jan 2007 → …

Conference

ConferenceSociety for Neuroscience 2007
Period1/01/07 → …

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  • Cite this

    Wong, K-F., Eckhoff, P., Holmes, P., & Cohen, J. (2007). Analysis of a biologically realistic model for saccade-countermanding tasks. In Unknown Host Publication Society for Neuroscience.