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Ruben Moreno

 

 

http://www.ft.uam.es/neurociencia/ruben/

E-mail: rmoreno@fsjd.org

 

(Foundation Sant Joan de Deu, Parc Sanitari Sant Joan de Deu and Universitat de Barcelona)

 

Wednesday 16th May 2012

16:00

 

B10 Seminar Room, Basement,

Alexandra House, 17 Queen Square, London, WC1N 3AR

 

 

"What variability and correlations tells us about cortical circuits and computations"

 

Neuronal activity in cortex is variable both spontaneously and during stimulation, and this variability is correlated across neurons. We will show that both variability and correlations have important impact on our knowledge about the underlying neuronal circuits and about the functions these circuits carry on. In particular, we will show in spontaneously active networks in monkey V1 that correlations imply that the underlying circuits have long-range connections with invariant-scale properties, although correlations per se decay fast with distance. Then, we will stress that the type of variability that we encounter in cortex (Poisson-like) is hard to reconcile with the behavior obtained from state of art balanced neuronal networks, unless probabilistic synapses are included. This suggests that the major source of variability in cortex arises from probabilistic synapses, begging the question of why the brain introduces noise. Finally, we will show that this injected noise has surprising computational implications, allowing to the cortical circuits to explore their states in a contrast-invariant manner.