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Nicholas Lesica

Wednesday 9th December 2015

Time: 4.00pm

 

Ground Floor Seminar Room

25 Howland Street, London, W1T 4JG

 

Nonlinear transfer of signal and noise correlations in cortical networks

 

Signal and noise correlations are a prominent feature of cortical
activity that reflect the structure and function of networks during
sensory processing. However, in addition to reflecting network
properties, correlations are also shaped by intrinsic neuronal
mechanisms. In this talk, I will describe how spike threshold
transforms correlations by creating nonlinear interactions between
signal and noise inputs; even when input noise correlation is
constant, spiking noise correlation varies with both the strength and
correlation of signal inputs. We characterized these effects
systematically in vitro in mice and demonstrated their impact on
sensory processing in vivo in gerbils. We also found that the effects
of nonlinear correlation transfer on cortical responses were stronger
in the synchronized state than in the desynchronized state, and showed
that they can be reproduced and understood in a model with a simple
threshold nonlinearity. Since these effects arise from an intrinsic
neuronal property, they are likely to be present across sensory
systems and, thus, our results are a critical step toward a general
understanding of how correlated spiking relates to the structure and
function of cortical networks.

Bio:

Nicholas Lesica is a research fellow at the UCL Ear Institute. He
received his undergraduate degree in electrical engineering and
computer science from MIT and his PhD in engineering sciences from
Harvard. He then did four years of postdoctoral training in auditory
neuroscience with Benedikt Grothe at the LMU in Munich and started his
own research group at UCL in 2010. His researched in focused on
understanding how populations of neurons throughout the brain work
together to process complex auditory scenes.