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Dynamical mechanism for sharp orientation tuning in an integrate-and-fire model of a cortical hypercolumn

Dynamical mechanism for sharp orientation tuning in an integrate-and-fire model of a cortical hypercolumn
Dynamical mechanism for sharp orientation tuning in an integrate-and-fire model of a cortical hypercolumn
Orientation tuning in a ring of pulse-coupled integrate-and-fire (IF) neurons is analyzed in terms of spontaneous pattern formation. It is shown how the ring bifurcates from a synchronous state to a non-phase-locked state whose spike trains are characterized by clustered but irregular fluctuations of the interspike intervals (ISIs). The separation of these clusters in phase space results in a localized peak of activity as measured by the time-averaged firing rate of the neurons. This generates a sharp orientation tuning curve that can lock to a slowly rotating, weakly tuned external stimulus. Under certain conditions, the peak can slowly rotate even to a fixed external stimulus. The ring also exhibits hysteresis due to the subcritical nature of the bifurcation to sharp orientation tuning. Such behavior is shown to be consistent with a corresponding analog version of the IF model in the limit of slow synaptic interactions. For fast synapses, the deterministic fluctuations of the ISIs associated with the tuning curve can support a coefficient of variation of order unity.
2473-2511
Bressloff, P.C.
19b476f1-f855-4acd-91ff-76bf0d91506a
Bressloff, N.W.
4f531e64-dbb3-41e3-a5d3-e6a5a7a77c92
Cowan, J.D.
faa8e825-58aa-4a31-a13b-2b76dd0efcb2
Bressloff, P.C.
19b476f1-f855-4acd-91ff-76bf0d91506a
Bressloff, N.W.
4f531e64-dbb3-41e3-a5d3-e6a5a7a77c92
Cowan, J.D.
faa8e825-58aa-4a31-a13b-2b76dd0efcb2

Bressloff, P.C., Bressloff, N.W. and Cowan, J.D. (2000) Dynamical mechanism for sharp orientation tuning in an integrate-and-fire model of a cortical hypercolumn. Neural Computation, 12 (11), 2473-2511.

Record type: Article

Abstract

Orientation tuning in a ring of pulse-coupled integrate-and-fire (IF) neurons is analyzed in terms of spontaneous pattern formation. It is shown how the ring bifurcates from a synchronous state to a non-phase-locked state whose spike trains are characterized by clustered but irregular fluctuations of the interspike intervals (ISIs). The separation of these clusters in phase space results in a localized peak of activity as measured by the time-averaged firing rate of the neurons. This generates a sharp orientation tuning curve that can lock to a slowly rotating, weakly tuned external stimulus. Under certain conditions, the peak can slowly rotate even to a fixed external stimulus. The ring also exhibits hysteresis due to the subcritical nature of the bifurcation to sharp orientation tuning. Such behavior is shown to be consistent with a corresponding analog version of the IF model in the limit of slow synaptic interactions. For fast synapses, the deterministic fluctuations of the ISIs associated with the tuning curve can support a coefficient of variation of order unity.

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Published date: 2000

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Local EPrints ID: 21588
URI: https://eprints.soton.ac.uk/id/eprint/21588
PURE UUID: a070b762-57c2-4c35-9f16-b030d1f465be

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Date deposited: 06 Feb 2007
Last modified: 17 Jul 2017 16:25

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