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Dynamics of propagation through long range horizontal connections: spatial facilitation and spike time alignment| old_uid | 14525 |
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| title | Dynamics of propagation through long range horizontal connections: spatial facilitation and spike time alignment |
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| start_date | 2014/10/22 |
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| schedule | 12h15-13h |
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| online | no |
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| summary | The architecture of long range horizontal connections in primary visual cortex suggests it implements geometrical constraints akin to the statistical distribution of local orientations in natural scenes. Propagating activity within this network is slow, owing to the thin unmyelinated axons running along the cortical surface. Such spatio-temporal organization results in delayed neuronal facilitation which can induce perceptual biases correlated to MEG evoked activity in primary visual cortex. I shall present psychophysical and MEG experimental data showing that response latencies to flashed aligned and non-aligned sequences of Gabor patches probe the cortical dynamics within this network and shall present a simple spike-time-alignment model (STAM) derived from these and other results where spatial facilitation induces a temporal alignment of the neuronal responses to elongated contours of varying contrast. STAM predicts that the variance of the population response latencies to elongated contours is reduced; the consequences of this prediction on further processing stages will be discussed. |
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| responsibles | Petitot |
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