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@PHDTHESIS{Korvasov:911034,
author = {Korvasová, Karolína},
title = {{P}ersistent firing and oscillations in the
septo-hippocampal system and their relation to locomotion},
volume = {86},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2022-04360},
isbn = {978-3-95806-654-0},
series = {Schriften des Forschungszentrums Jülich Reihe Information
/ Information},
year = {2022},
note = {Dissertation, RWTH Aachen University, 2022},
abstract = {The medial septum, diagonal band of Broca has received most
attention as a putative pacemaker of the hippocampal theta
rhythm. However, due to its high interconnectivity with
various cortical and subcortical regions, the medial septum
is involved in a variety of neural processes. This thesis
focuses on the relation between medial septal spiking
activity, hippocampal theta rhythm and locomotion. It was
previously demonstrated that theta-periodic optogenetic
activation of medial septal glutamatergic neurons entrains
hippocampal theta oscillation and initiates
persistentlocomotion of the animal. We showed that
hippocampal theta oscillation and locomotion, both
persisting after the stimulus offset, can be induced by a
brief continuous light stimulation of medial septal
glutamatergic neurons. The hippocampal theta rhythm is not
necessary for inducing persistent locomotion, as locomotion
initiation is not affected by blocking synaptic transmission
in the medial septum that abolishes the hippocampal theta.
Furthermore, we observed persistent spiking activity of the
medial septal neurons, lasting for many seconds after the
stimulus offset.To test whether the persistent activity is
generated locally in the medial septum, we repeated the
stimulation experiment in an acute medial septal slice
preparation. The persistent activity had a shorter duration
than in vivo, but was present both in the intact slice and
with blocked synaptic transmission, indicating that the
persistent firing is a result of intrinsic dynamics of
medial septal glutamatergic neurons. Further analysis of
spontaneous spiking activity of neurons in the acute medial
septal slice preparation revealed the existence of
theta-rhythmic neurons that synchronizetheir firing,
suggesting that the medial septum can generate the theta
oscillation independently of external feedforward and
feedback input. Even though medial septal synaptic
connectivity is necessary for the hippocampal theta rhythm,
our results suggest that the theta-rhythmic firing is a
result of intrinsic cellular dynamics and a low level of
synchrony can be achieved without synaptic coupling. It
remains an open question how the septal theta-rhythmic input
is transformed into a travelling theta wave observed in the
hippocampus. The last part of the thesis offers a framework
for studying the generation of periodic travelling waves in
spiking neural networks. We developed a parameter mapping
between a discrete network of neurons and apopulation model
that describes the spatio-temporal spread of activity as a
continuousprocess. Using this mapping, we derived conditions
for the existence of periodictravelling waves in the spiking
neural network.},
cin = {INM-6 / IAS-6},
cid = {I:(DE-Juel1)INM-6-20090406 / I:(DE-Juel1)IAS-6-20130828},
pnm = {899 - ohne Topic (POF4-899)},
pid = {G:(DE-HGF)POF4-899},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
urn = {urn:nbn:de:0001-2022112351},
url = {https://juser.fz-juelich.de/record/911034},
}