2134/825
P.C. Bressloff
P.C.
Bressloff
N.W. Bressloff
N.W.
Bressloff
J.D. Cowan
J.D.
Cowan
Dynamical mechanism for sharp orientation tuning in an integrate-and-fire model of a cortical hypercolumn.
Loughborough University
2006
untagged
Mathematical Sciences not elsewhere classified
2006-02-15 10:29:49
Preprint
https://repository.lboro.ac.uk/articles/preprint/Dynamical_mechanism_for_sharp_orientation_tuning_in_an_integrate-and-fire_model_of_a_cortical_hypercolumn_/9384476
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 inter-spike 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
synpatic interactions. For fast synapses, the deterministic fluctuations of the ISIs associated
with the tuning curve can support a coefficient of variation (CV) of order unity.