bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2022,
Volume and Issue:
unknown
Published: March 25, 2022
Abstract
Mixed
affective
states
in
bipolar
disorder
(BD)
is
a
common
psychiatric
condition
that
occurs
when
symptoms
of
the
two
opposite
poles
coexist
during
an
episode
mania
or
depression.
A
four-dimensional
model
by
A.
Goldbeter
[27,
28]
rests
upon
notion
manic
and
depressive
are
produced
competing
auto-inhibited
neural
networks.
Some
rich
dynamics
this
can
produce,
include
complex
rhythms
formed
both
small-amplitude
(subthreshold)
large-amplitude
(suprathreshold)
oscillations
could
correspond
to
mixed
states.
These
commonly
referred
as
mode
(MMOs)
they
have
already
been
studied
many
different
contexts
[7,
50].
In
order
accurately
explain
these
one
has
apply
mathematical
apparatus
makes
full
use
timescale
separation
between
variables.
Here
we
framework
multiple-timescale
BD
understand
mechanisms
underpinning
observed
changing
mood.
We
show
be
understood
MMOs
due
so-called
folded-node
singularity
.
Moreover,
explore
bifurcation
structure
system
provide
possible
biological
interpretations
our
findings.
Finally,
robustness
regime
stochastic
noise
propose
minimal
three-dimensional
which,
with
addition
noise,
exhibits
similar
yet
purely
noise-driven
dynamics.
The
broader
significance
work
introduce
tools
used
analyse
potentially
control
future,
more
biologically
grounded
models
BD.
Nonlinear Dynamics,
Journal Year:
2022,
Volume and Issue:
108(4), P. 4261 - 4285
Published: April 19, 2022
Abstract
We
report
a
detailed
analysis
on
the
emergence
of
bursting
in
recently
developed
neural
mass
model
that
includes
short-term
synaptic
plasticity.
Neural
models
can
mimic
collective
dynamics
large-scale
neuronal
populations
terms
few
macroscopic
variables
like
mean
membrane
potential
and
firing
rate.
The
present
one
is
particularly
important,
as
it
represents
an
exact
meanfield
limit
synaptically
coupled
quadratic
integrate
fire
(QIF)
neurons.
Without
dynamics,
periodic
external
current
with
slow
frequency
$$\varepsilon
$$
ε
lead
to
burst-like
dynamics.
patterns
be
understood
using
singular
perturbation
theory,
specifically
slow–fast
dissection.
With
timescale
separation
leads
variety
phenomena
their
role
for
becomes
inordinately
more
intricate.
Canards
are
crucial
understand
route
bursting.
They
describe
trajectories
evolving
nearby
repelling
locally
invariant
sets
system
exist
at
transition
between
subthreshold
Near
=
0$$
xmlns:mml="http://www.w3.org/1998/Math/MathML">ε=0
,
we
peculiar
jump-on
canards
which
block
continuous
In
biologically
plausible
-regime,
this
bursts
emerge
via
consecutive
spike-adding
transitions.
onset
complex
involves
mixed-type-like
torus
form
very
first
spikes
burst
follow
fast-subsystem
cycles.
numerically
evidence
same
mechanisms
responsible
QIF
network
plastic
synapses.
main
conclusions
apply
network,
owing
exactness
limit.
PLoS Computational Biology,
Journal Year:
2022,
Volume and Issue:
18(2), P. e1009752 - e1009752
Published: Feb. 24, 2022
Bursting
is
one
of
the
fundamental
rhythms
that
excitable
cells
can
generate
either
in
response
to
incoming
stimuli
or
intrinsically.
It
has
been
a
topic
intense
research
computational
biology
for
several
decades.
The
classification
bursting
oscillations
systems
subject
active
since
early
1980s
and
still
ongoing.
As
by-product,
it
establishes
analytical
numerical
foundations
studying
complex
temporal
behaviors
multiple
timescale
models
cellular
activity.
In
this
review,
we
first
present
seminal
works
Rinzel
Izhikevich
classifying
patterns
systems.
We
recall
complementary
mathematical
approach
by
Bertram
colleagues,
then
Golubitsky
which,
together
with
Rinzel-Izhikevich
proposals,
provide
state-of-the-art
these
classifications.
Beyond
classical
approaches,
review
recent
example
falls
outside
previous
Generalizing
leads
us
propose
an
extended
classification,
which
requires
analysis
both
fast
slow
subsystems
underlying
slow-fast
model
allows
dissection
larger
class
bursters.
Namely,
general
framework
subthreshold
superthreshold
oscillations.
A
new
bursters
at
least
2
variables
added,
denote
folded-node
bursters,
convey
idea
bursts
are
initiated
annihilated
via
singularity.
Key
mechanism
so-called
canard
duck
orbits,
organizing
underpinning
excitability
structure.
describe
main
families
depending
upon
phase
(active/spiking
silent/nonspiking)
cycle
during
dynamics
occurs.
classify
give
examples
minimal
displaying
novel
patterns.
Finally,
biophysical
reinterpreting
generic
conductance-based
episodic
burster
as
burster,
showing
associated
explain
its
over
parameter
region
than
subsystem
approach.
PLoS Computational Biology,
Journal Year:
2020,
Volume and Issue:
16(11), P. e1008430 - e1008430
Published: Nov. 9, 2020
Epilepsy
is
a
dynamic
and
complex
neurological
disease
affecting
about
1%
of
the
worldwide
population,
among
which
30%
patients
are
drug-resistant.
characterized
by
recurrent
episodes
paroxysmal
neural
discharges
(the
so-called
seizures),
manifest
themselves
through
large-amplitude
rhythmic
activity
observed
in
depth-EEG
recordings,
particular
local
field
potentials
(LFPs).
The
signature
characterizing
transition
to
seizures
involves
oscillatory
patterns,
could
serve
as
marker
prevent
seizure
initiation
triggering
appropriate
therapeutic
neurostimulation
methods.
To
investigate
such
protocols,
neurophysiological
lumped-parameter
models
at
mesoscopic
scale,
namely
mass
models,
powerful
tools
that
not
only
mimic
LFP
signals
but
also
give
insights
on
mechanisms
related
different
stages
seizures.
Here,
we
analyze
multiple
time-scale
dynamics
model
explain
underlying
structure
oscillations
before
initiation.
We
population-specific
effects
stimulation
dependence
parameters
synaptic
timescales.
In
particular,
show
intermediate
frequencies
(>20
Hz)
can
abort
if
timescale
difference
pronounced.
Those
results
have
potential
design
brain
protocols
based
properties
tissue.
Physics of Life Reviews,
Journal Year:
2024,
Volume and Issue:
51, P. 423 - 441
Published: Nov. 13, 2024
Traditionally,
mathematical
models
in
ecology
placed
an
emphasis
on
asymptotic,
long-term
dynamics.
However,
a
large
number
of
recent
studies
highlighted
the
importance
transient
dynamics
ecological
and
eco-evolutionary
systems,
particular
'long
transients'
that
can
last
for
hundreds
generations
or
even
longer.
Many
as
well
empirical
indicated
system
function
long
time
certain
state
regime
(a
'metastable
regime')
but
later
exhibits
abrupt
transition
to
another
not
preceded
by
any
parameter
change
(or
following
occurred
before
transition).
This
scenario
where
tipping
occurs
without
apparent
source
shift
is
also
referred
'metastability'.
Despite
considerable
evidence
presence
transients
real-world
systems
models,
until
recently
research
into
long-living
has
remained
its
infancy,
largely
lacking
systematisation.
Within
past
decade,
however,
substantial
progress
been
made
creating
unifying
theory
deterministic
stochastic
systems.
considerably
accelerated
further
transients,
those
characterised
more
complicated
patterns
and/or
underlying
mechanisms.
The
main
goal
this
review
provide
overview
related
shifts
We
pay
special
attention
role
environmental
stochasticity,
effect
multiple
timescales
(slow-fast
systems),
spatial
patterns,
relation
between
synchronisation.
discuss
current
challenges
open
questions
understanding
with
applications
ecosystems
The Journal of Mathematical Neuroscience,
Journal Year:
2021,
Volume and Issue:
11(1)
Published: Sept. 16, 2021
Abstract
Mathematical
models
at
multiple
temporal
and
spatial
scales
can
unveil
the
fundamental
mechanisms
of
critical
transitions
in
brain
activities.
Neural
mass
(NMMs)
consider
average
dynamics
interconnected
neuronal
subpopulations
without
explicitly
representing
underlying
cellular
activity.
The
mesoscopic
level
offered
by
neural
formulation
has
been
used
to
model
electroencephalographic
(EEG)
recordings
investigate
various
cerebral
mechanisms,
such
as
generation
physiological
pathological
In
this
work,
we
a
NMM
widely
accepted
context
epilepsy,
which
includes
four
interacting
with
different
synaptic
kinetics.
Due
resulting
three-time-scale
structure,
yields
complex
oscillations
relaxation
bursting
types.
By
applying
principles
geometric
singular
perturbation
theory,
existence
canard
solutions
detail
how
they
organize
excitability
properties
model.
particular,
show
that
boundaries
between
epileptic
discharges
background
activity
are
determined
solutions.
Finally
report
canard-mediated
small-amplitude
frequency-specific
simulated
local
field
potentials
for
decreased
inhibition
conditions.
Interestingly,
actually
observed
intracerebral
EEG
signals
recorded
patients
during
pre-ictal
periods,
close
seizure
onsets.
Mathematics,
Journal Year:
2023,
Volume and Issue:
11(13), P. 2874 - 2874
Published: June 27, 2023
Canards
are
a
type
of
transient
dynamics
that
occur
in
singularly
perturbed
systems,
and
they
specific
types
solutions
with
varied
dynamic
behaviours
at
the
boundary
region.
This
paper
introduces
emergence
development
canard
phenomena
neuron
model.
The
singular
perturbation
system
general
model
is
investigated,
link
between
transition
from
to
summarised.
First,
relationship
folded
saddle-type
parabolic
burster,
as
well
firing-threshold
manifold,
established.
Moreover,
association
mixed-mode
oscillation
node
unique.
Furthermore,
connection
limit-cycle
(singular
Hopf
bifurcation)
stated.
In
addition,
torus
tonic
spiking
bursting
illustrated.
Finally,
manifestations
these
demonstrated,
such
bifurcation,
folded-node
canard,
“blue
sky
catastrophe”.
summary
outlook
this
point
realistic
possibility
canards,
which
have
not
yet
been
discovered