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The influence of fixational eye movements on neural correlated activity in the first stages of the visual system| old_uid | 1864 |
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| title | The influence of fixational eye movements on neural correlated activity in the first stages of the visual system |
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| start_date | 2006/11/30 |
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| schedule | 13h45 |
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| online | no |
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| summary | Under natural viewing conditions, the physiological instability of the eye keeps, even during fixation, the retinal projection of the visual input in constant motion. In this talk I will examine the impact of these microscopic eye movements on cell activities at the first stages of the visual system. Using a quasi-linear model of LGN (Lateral Geniculate Nucleus) units and V1 simple cells I will derive a general analytical expression for the second-order statistics of thalamo-thalamic and thalamo-cortical correlated activity. It will be shown that, in the presence of natural visual input, the natural jiittering of the eye introduces in the retinal signals a spatially uncorrelated term which strongly influences correlated activity in our model. Furthermore, during thalamo-cortical development this uncorrelated term produces, a regime of thalamo-cortical activity similar to that present before eye opening and compatible with the Hebbian maturation of simple cell receptive fields. Finally, during normal visual behavior, fixational eye movements contribute to diminishing the correlation between neighboring LGN units thus leading to a more efficient coding of the visual information. |
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| responsibles | Perthame |
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