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SUMMARY:Self-organized criticality emerges when synapses compete to potent
 iate
DTSTART:20130516T134500
DTSTAMP:20260408T071053Z
UID:7b9df762aafeabd73203a277ee9cb45e55ba09af8536459823994feb
CATEGORIES:Conferences - Seminars
DESCRIPTION:Eilif MULLER\, The Blue Brain Project\, EPFL\nSpontaneous low-
 frequency synchronous bursting is an indicator of insufficient inhibitory 
 control of local recurrent excitation in neural tissues or sufficiently de
 tailed neuronal network models.  Such rhythmic activity in recurrent netw
 orks poses significant problems for a broad class of STDP models commonly 
 studied. The strong potentiation at many synapses due to bursts reinforces
  bursting and can trigger an upward spiral of potentiation towards non-bio
 logical extremes.  To oppose this trend\, we hypothesized that synapses i
 n close spatial proximity are in competition during network bursts for res
 ources needed to potentiate\, and that this competition is sufficient to c
 ounter-balance run-away potentiation. We explored experimentally whether n
 etwork bursts interfere with STDP pairing protocols. In particular\, we fo
 und that pairing protocols yielding potentiation switched to depression if
  a burst preceded the STDP protocol by 20ms\, suggesting a confirmation of
  the hypothesis.  We developed a novel phenomenological model of resource
  consumption compatible with common STDP rules\, which accounts for compet
 ition for resources to undergo potentiation. We show in a point neuron net
 work that this model counter-balances run-away potentiation while leaving 
 the STDP rule otherwise unperturbed. The resulting network states are desy
 nchronized\, and exhibit rare bursting events of highly variable amplitude
 s governed by a power-law distribution - a signature of self-organized cri
 ticality
LOCATION:AAC 120 http://plan.epfl.ch/?room=AAC120
STATUS:CANCELLED
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