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Motion representation in V1 : a voltage-sensitive dye imaging study| old_uid | 3866 |
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| title | Motion representation in V1 : a voltage-sensitive dye imaging study |
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| start_date | 2008/01/21 |
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| schedule | 11h-12h30 |
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| online | no |
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| summary | In this talk, I will present evidence that the retinotopic organisation of V1 is an ideal platform to represent motion, both in the anesthetized cat and the behaving monkey preparation. The columnar organisation of V1 allows for the parallel encoding of many visual properties, such as orientation, direction, position, spatial frequency, ocular dominance. These properties emerge from strong recurrent excitatory and inhibitory local networks that shape the incoming thalamic input. However, information is also spread laterally through intracortical horizontal axons. In the cat and in the monkey, the spatio-temporal characteristic of this horizontal spread can be directly imaged using VSDI. An important functional consequence of this spread is that any local input will not only activate its retinotopic cortical representation, but also generate a wave of activity that will prime the surrounding cortex. Any subsequent stimulation will therefore generate a feedforward activation that will be integrated by a pre-activated cortex. I will show that the interaction between the two waves of activity, the horizontal and the feedforward, is highly non-linear and allows for the emergence of a smooth propagation of activity. This propagation of activity may be the substrate of a low-level cortical representation of motion. |
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| responsibles | Information non disponible |
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