A BME Kognitív Tudományi Tanszék szeretettel vár
mindenkit tanszéki
szeminárium sorozatának következő hétfői előadására:
The Department of Cognitive Science at BME cordially invites
you to the next
talk in its lecture series:
Nádasdy Zoltán
Post-Doctoral Fellow
The Andersen Lab
California Institute of Technology
The
neuronal phase code
(Encoding and decoding information by the phase of action potentials)
December 8., hétfő - 15:00. BME, XI., Stoczek u. 2., St.
ép., 320.-as terem.
Monday, December 8th, 15:00. BME, Budapest, Stoczek u. 2, St.
building, room 320.
Abstract:
Experimental evidence, such as task-dependent coherency
between single-unit activity and local field potentials (LFPs),
together with
the dependency of action potential (AP) initiation on the subthreshold
membrane
oscillation (SMO) suggest that: i) the probability of action potentials
is
controlled by a common oscillatory mechanism; ii) the SMOs across
individual
neurons are not independent but rather form a coherent field of
oscillations;
and iii) nearly-synchronized SMOs may propagate through neuronal
connections,
creating a constant-phase gradient of SMO between neighbor neurons.
Based on
these assumptions, we formulated a model in which neurons encode
information by
the phase of APs relative to the SMO. The model consists of four
stages: encoding
with phase, gamma alignment, information transfer, and reconstruction.
We
demonstrated by means of simulations that information encoded by the
phase of
APs can reliably be transferred and reconstructed at distant target
areas. Moreover, since the
phase code is a compressed representation of the spatio-temporal
features of
the stimulus, it enables the transfer of information in parallel
pathways
without distortion from conductance differences. We illustrate by
examples how
phase coding may account for a number of unresolved physiological
observations
related to sparse coding, motion processing, phase precession, and
invariance
detection, as well as anatomical principles, such as the columnar
organization
and grid cell architecture. Furthermore, we show empirical evidence for
stimulus-dependent phase coding in V1 from simultaneous single-unit and
LFP
recordings.
Keresztes Attila
BME-Kognitív Tudományi
Tanszék
BME-Cognitive Science
Department
akeresztes@cogsci.bme.hu
keresztes.attila@gmail.com