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Talk by Dr. Björn Kampa

Junior Group Leader, Vision Lab

Brain Research Institute, University of Zurich

begin
13.Jun.2012 16:00
end
13.Jun.2012 17:00

A Multi-Scale Approach to Cortical Representation of Visual Scenery

How is our visual environment represented and processed in the brain? In my lab,

we seek answers to this fundamental question with a multi-scale approach

combining two-photon imaging with electrophysiological recordings. Neurons in

the visual cortex have a receptive field like a keyhole through which they look at

the scenery in front of the eyes. Visual input from the area surrounding the

receptive field fails to induce neuronal firing but can modulate the neuronal

responses to receptive field stimulation. Recent studies have shown that natural

movie stimulation beyond the receptive field leads to reduced but more precise

neuronal responses. We have established this paradigm in mouse visual cortex

where we investigate the interaction of incoming sensory evidence with internal

feedback from surrounding and higher visual areas. We find precise and sparse

responses to presentations of different visual scenes. Our results suggest a

population code, where the visual environment is dynamically represented in the

activation of distinct functional sub-networks. Furthermore, we find higher visual

areas to be well tuned to the characteristics of natural scenes indicating the role

of their feedback in visual perception. Integrated studies at multiple scales from

neuronal dendrites to populations of neurons together with their input from

higher visual areas will assemble the puzzle of local computation in visual cortex

revealing the picture of how we perceive and interpret visual scenes.


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