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@INPROCEEDINGS{Duarte:186421,
author = {Duarte, Renato and Morrison, Abigail},
title = {{S}ynaptic adaptation stabilizes sequential stimulus
representations},
reportid = {FZJ-2015-00497},
year = {2014},
abstract = {Throughout our everyday experience, we are continuously
exposed to dynamic and highly complexstreams of multimodal
sensory information, which we tend to perceive as a series
of discrete andcoherently bounded sub-sequences [1]. While
these 'perceptual events' [2] are unfolding,
activerepresentations of the relevant stimulus features
(such as identity, duration, intensity, etc.) aremaintained
and ought to be sufficiently discernible by the distributed
responses of specifically tunedneuronal populations,
transiently associated into coherent ensembles [3].
Achieving suchdiscriminable responses constitutes a
fundamental, primary function of neocortical
circuits,necessary for specialized information processing to
take place and must rely on their ability to
selforganize,resorting to a complex interaction of various
activity-dependent modifications of synapticand intrinsic
neuronal properties.Such modifications ought to be robust
and reliable enough to endow neuronal circuits with
theability to dynamically adopt relevant representations of
time-varying, sequential events in astimulus- and
state-dependent manner, while maintaining the necessary
sensitivity to allow globalshifts in representational space
when necessary and to learn from and operate upon
relevantspatiotemporal dependencies between events. The
current state of the circuit, which largelyinfluences the
dynamical properties of such representations, is primarily
determined by the ongoing,internally generated activity,
which sets the ground state from which input-specific
transformationsemerge.In this work, we study the properties
of biologically realistic networks of LIF neurons,
withdifferentially modulated, dynamic excitation and
inhibition, combining well established as well asmore recent
phenomenological models of synaptic plasticity [4, 5]. We
begin by demonstrating thattiming-dependent synaptic
plasticity mechanisms have an important role to play in the
activemaintenance of an ongoing dynamics characterized by
asynchronous and irregular firing, closelyresembling
cortical activity in vivo. Incoming stimuli, acting as
perturbations of the local balance ofexcitation and
inhibition, require fast adaptive responses to prevent the
development of unstableactivity regimes, which we
objectively link between to a reduced generic computational
capacity.Additionally, we demonstrate that the action of
plasticity shapes and stabilizes the transient networkstates
exhibited in the presence of sequentially presented stimulus
events, allowing the developmentof adequate and discernible
stimulus representations. The main feature responsible for
the increaseddiscriminability of stimulus-driven population
responses in plastic networks is shown to be
thedecorrelating action of inhibitory plasticity and the
consequent maintenance of the asynchronousirregular dynamic
regime both for ongoing activity and stimulus-driven
responses, whereasexcitatory plasticity is shown to play
only a marginal role.References:[1] Schapiro, A. C., Rogers,
T. T., Cordova, N. I., Turk-Browne, N. B., and Botvinick, M.
M.(2013), Neural representations of events arise from
temporal community structure., NatureNeuroscience, 16, 4,
486 92, doi:10.1038/nn.3331[2] Zacks, J. M., Speer, N. K.,
Swallow, K. M., Braver, T. S., and Reynolds, J. R. (2007),
Eventperception: a mind-brain perspective., Psychological
Bulletin, 133, 2, 273–93,
doi:10.1037/0033-2909.133.2.273[3] Singer, W. (2013),
Cortical dynamics revisited., Trends in Cognitive Sciences,
17, 12, 616–26,doi:10.1016/j.tics.2013.09.006[4] Vogels,
T. P., Sprekeler, H., Zenke, F., Clopath, C., and Gerstner,
W. (2011), Inhibitory plasticitybalances excitation and
inhibition in sensory pathways and memory networks.,
Science, 334, 6062,569–73, doi:10.1126/science.1211095[5]
Morrison, A., Diesmann, M., and Gerstner, W. (2008),
Phenomenological models of synapticplasticity based on spike
timing, Biological Cybernetics, 98, 459–478,
doi:10.1007/s00422-008-0233-1},
month = {Dec},
date = {2014-12-16},
organization = {7th International Workshop in Guided
Self-Organization, Freiburg (Germany),
16 Dec 2014 - 18 Dec 2014},
subtyp = {Invited},
cin = {INM-6 / IAS-6},
cid = {I:(DE-Juel1)INM-6-20090406 / I:(DE-Juel1)IAS-6-20130828},
pnm = {311 - Signaling pathways, cell and tumor biology (POF2-311)
/ 89572 - (Dys-)function and Plasticity (POF2-89572) /
W2Morrison - W2/W3 Professorinnen Programm der
Helmholtzgemeinschaft (B1175.01.12)},
pid = {G:(DE-HGF)POF2-311 / G:(DE-HGF)POF2-89572 /
G:(DE-HGF)B1175.01.12},
typ = {PUB:(DE-HGF)6},
url = {https://juser.fz-juelich.de/record/186421},
}