The operating regime of local computations in primary visual cortex
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The operating regime of local computations in primary visual cortexAutor(es)
Data
2009-02-16Cita bibliográfica
Stimberg M, Wimmer K, Martin R, et al. The operating regime of local computations in primary visual cortex. Cerebral Cortex. 2009;19(9):2166-2180
Resumo
[Abstract] In V1, local circuitry depends on the position in the orientation map: close to pinwheel centers, recurrent inputs show variable orientation preferences; within iso-orientation domains, inputs are relatively uniformly tuned. Physiological properties such as cell's membrane potentials, spike outputs, and temporal characteristics change systematically with map location. We investigate in a firing rate and a Hodgkin–Huxley network model what constraints these tuning characteristics of V1 neurons impose on the cortical operating regime. Systematically varying the strength of both recurrent excitation and inhibition, we test a wide range of model classes and find the likely models to account for the experimental observations. We show that recent intracellular and extracellular recordings from cat V1 provide the strongest evidence for a regime where excitatory and inhibitory recurrent inputs are balanced and dominate the feed-forward input. Our results are robust against changes in model assumptions such as spatial extent and strength of lateral inhibition. Intriguingly, the most likely recurrent regime is in a region of parameter space where small changes have large effects on the network dynamics, and it is close to a regime of “runaway excitation,” where the network shows strong self-sustained activity. This could make the cortical response particularly sensitive to modulation.
Palabras chave
Bayesian data analysis
Computational model
Networks dynamics
Orientation tuning
Reverse correlation
Computational model
Networks dynamics
Orientation tuning
Reverse correlation
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This is the pre-copyedited, author-produced PDF of an article accepted for publication in "Cerebral Cortex" following peer review. The version of record is avaliable online at Oxford Journals.