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V1 neurons can distinguish between motion in the world and visual displacements due to eye movements| old_uid | 12347 |
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| title | V1 neurons can distinguish between motion in the world and visual displacements due to eye movements |
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| start_date | 2013/04/15 |
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| schedule | 10h45 |
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| online | no |
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| summary | How do perceptual systems differentiate between self-motion and motion in the world? This major question in neuroscience has special importance in vision. We can easily distinguish between real world motion and a comparable displacement of the image over the retina due to an eye movement, despite equivalent retinal stimulation for externally and internally generated motion. However, how the brain performs this operation or which brain areas are involved remains unknown.
We recorded single neuron activity from area V1 and compared the responses triggered by microsaccades (small-magnitude saccades that occur while attempting to fixate) to the responses induced by stimulus motion mimicking microsaccades. Our experimental set up allowed us to determine 1) whether area V1 neurons can differentiate between internal and external motion, and 2) the contribution of retinal versus non-retinal sources to microsaccade-driven neuronal responses in area V1.
We found that neuronal responses to 'real' microsaccades were generally biphasic: a quick and dramatic increase over baseline was typically followed by a smaller and slower trough below baseline, whereas responses to 'simulated' microsaccades included an excitatory peak but no trough.
The differential neural response to real vs simulated microsaccades indicates that area V1 neurons can distinguish between internally and externally generated motion. These findings also suggest that excitatory responses to real microsaccades result from the displacement of the visual stimulus over the classical receptive field, with the subsequent inhibition reflecting non-retinal sources. Our results help to delineate and constrain the role of area V1 in information processing, visual stability and/or perceptual suppression during microsaccades. |
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| responsibles | Blancho |
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