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Variations of coding accuracy by population of neurons after brief stimulus presentation| old_uid | 5307 |
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| title | Variations of coding accuracy by population of neurons after brief stimulus presentation |
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| start_date | 2008/09/29 |
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| schedule | 16h |
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| online | no |
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| details | organized by Daniele Marinazzo |
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| summary | How the stimulus properties are represented by neural systems, ie. the neural coding, is being debated for a long time. A
striking feature difficulting those studies is that the neural coding
seems to be adaptive, changing in a range of many different time
scales. To address this problem, most of the electrophysiological
research has been done at individual neurons. However, action,
perception, learning and memory are believed to be encoded by
population of neurons, and more specifically in different patterns of
synaptic connectivity or neural wiring.
Very recently, the neural coding by population of neurons has started
to be approached with experiments, by, for instance, using
multi-electrode recordings or optimal imaging of population of
neurons. However, a quantification of changes in population coding is
difficult to address experimentally. It requires to collect enormous
amount of data and this is an essential restriction to
experimentalists. Alternatively, one can address this problem by
modeling a population of neurons connected by a specific pattern of
synaptic connectivity.
In general, after stimulus presentation individual neurons reduce
their activity, they adapt and save metabolic expenses on coding a
repetitive stimulus, while the population of neurons reproduce
perceptual changes after adaptation, e.g. tilt after-effects.
I will present some results of how the population coding changes after
brief presentation of general stimuli. Thanks to the modeling
approach, I will discuss how the accuracy depends on different
factors: 1) number of neurons in the population 2) different forms of
adaptation, considering either synaptic or neural mechanisms 3)
intrinsic variability of individual neurons.
Based on an analysis using Fisher information, stimulus
discriminability increased for stimuli close to the adapting stimulus.
These results suggest that visual adaptation is functionally
advantageous from an information coding perspective and validate the
"efficient neural coding hypothesis." |
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| responsibles | van Vreeswijk, Battaglia |
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