bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2022,
Номер
unknown
Опубликована: Окт. 5, 2022
Abstract
Metabolic
limitations
within
the
brain
frequently
arise
in
context
of
aging
and
disease.
As
largest
consumers
energy
brain,
ion
pumps
that
maintain
neuronal
membrane
potential
are
most
affected
when
supply
becomes
limited.
To
characterize
effects
such
limitations,
we
analyze
gradients
present
Larter-Breakspear
neural
mass
model.
We
show
existence
locations
Neimark-Sacker
period-doubling
bifurcations
sodium,
calcium,
potassium
reversal
potentials,
demonstrate
these
form
physiologically
relevant
bounds
gradient
variability.
Within
bounds,
how
depolarization
will
cause
decreased
activity.
also
decreases
inter-regional
coherence,
causing
a
shift
critical
point
at
which
coupling
occurs
thereby
inducing
loss
synchrony
between
regions.
In
this
way,
model
captures
variability
microscale
level
propagates
changes
to
macroscale
congruent
with
those
observed
human
neuroimaging
studies.
Proceedings of the National Academy of Sciences,
Год журнала:
2024,
Номер
121(3)
Опубликована: Янв. 10, 2024
The
brain
is
composed
of
complex
networks
interacting
neurons
that
express
considerable
heterogeneity
in
their
physiology
and
spiking
characteristics.
How
does
this
neural
influence
macroscopic
dynamics,
how
might
it
contribute
to
computation?
In
work,
we
use
a
mean-field
model
investigate
computation
heterogeneous
networks,
by
studying
the
cell
thresholds
affects
three
key
computational
functions
population:
gating,
encoding,
decoding
signals.
Our
results
suggest
serves
different
types.
inhibitory
interneurons,
varying
degree
spike
threshold
allows
them
gate
propagation
signals
reciprocally
coupled
excitatory
population.
Whereas
homogeneous
interneurons
impose
synchronized
dynamics
narrow
dynamic
repertoire
neurons,
act
as
an
offset
while
preserving
neuron
function.
Spike
also
controls
entrainment
properties
periodic
input,
thus
affecting
temporal
gating
synaptic
inputs.
Among
increases
dimensionality
improving
network’s
capacity
perform
tasks.
Conversely,
suffer
for
function
generation,
but
excel
at
encoding
via
multistable
regimes.
Drawing
from
these
findings,
propose
intra-cell-type
mechanism
sculpting
local
circuits
permitting
same
canonical
microcircuit
be
tuned
diverse
Imaging Neuroscience,
Год журнала:
2024,
Номер
2, С. 1 - 14
Опубликована: Апрель 23, 2024
Aging
is
associated
with
impaired
signaling
between
brain
regions
when
measured
using
resting-state
fMRI.
This
age-related
destabilization
and
desynchronization
of
networks
reverses
itself
the
switches
from
metabolizing
glucose
to
ketones.
Here,
we
probe
mechanistic
basis
for
these
effects.
First,
confirmed
their
robustness
across
measurement
modalities
two
datasets
acquired
EEG
(
Neural Computation,
Год журнала:
2024,
Номер
36(8), С. 1476 - 1540
Опубликована: Июль 19, 2024
Abstract
Pulse-coupled
spiking
neural
networks
are
a
powerful
tool
to
gain
mechanistic
insights
into
how
neurons
self-organize
produce
coherent
collective
behavior.
These
use
simple
neuron
models,
such
as
the
θ-neuron
or
quadratic
integrate-and-fire
(QIF)
neuron,
that
replicate
essential
features
of
real
dynamics.
Interactions
between
modeled
with
infinitely
narrow
pulses,
spikes,
rather
than
more
complex
dynamics
synapses.
To
make
these
biologically
plausible,
it
has
been
proposed
they
must
also
account
for
finite
width
which
can
have
significant
impact
on
network
However,
derivation
and
interpretation
pulses
contradictory,
pulse
shape
is
largely
unexplored.
Here,
I
take
comprehensive
approach
coupling
in
QIF
θ-neurons.
argue
activate
voltage-dependent
synaptic
conductances
show
implement
them
their
effect
last
through
phase
after
spike.
Using
an
exact
low-dimensional
description
globally
coupled
neurons,
prove
instantaneous
interactions
oscillations
emerge
due
effective
mean
voltage.
analyze
by
means
family
smooth
functions
arbitrary
symmetric
asymmetric
shapes.
For
resulting
voltage
not
very
synchronizing
but
slightly
skewed
spike
readily
generate
oscillations.
The
results
unveil
synchronization
mechanism
at
heart
emergent
behavior,
facilitated
complementary
traditional
transmission
networks.
Physical review. E,
Год журнала:
2025,
Номер
111(1)
Опубликована: Янв. 24, 2025
We
investigate
a
large
ensemble
of
quadratic
integrate-and-fire
neurons
with
heterogeneous
input
currents
and
adaptation
variables.
Our
analysis
reveals
that,
for
specific
class
adaptation,
termed
spike-frequency
the
high-dimensional
system
can
be
exactly
reduced
to
low-dimensional
ordinary
differential
equations,
which
describes
dynamics
three
mean-field
variables:
population's
firing
rate,
mean
membrane
potential,
variable.
The
resulting
rate
equations
(FREs)
uncover
key
generic
feature
networks
adaptation:
Both
center
width
distribution
neurons'
frequencies
are
reduced,
this
largely
promotes
emergence
collective
synchronization
in
network.
findings
further
supported
by
bifurcation
FREs,
accurately
captures
spiking
neuron
network,
including
phenomena
such
as
oscillations,
bursting,
macroscopic
chaos.
Biological Cybernetics,
Год журнала:
2022,
Номер
117(1-2), С. 5 - 19
Опубликована: Дек. 1, 2022
Neural
mass
models
(NMMs)
are
designed
to
reproduce
the
collective
dynamics
of
neuronal
populations.
A
common
framework
for
NMMs
assumes
heuristically
that
output
firing
rate
a
neural
population
can
be
described
by
static
nonlinear
transfer
function
(NMM1).
However,
recent
exact
mean-field
theory
quadratic
integrate-and-fire
(QIF)
neurons
challenges
this
view
showing
mean
is
not
state
but
follows
two
coupled
differential
equations
(NMM2).
Here
we
analyze
and
compare
these
descriptions
in
presence
second-order
synaptic
dynamics.
First,
derive
mathematical
equivalence
between
infinitely
slow
synapse
limit,
i.e.,
show
NMM1
an
approximation
NMM2
regime.
Next,
evaluate
applicability
limit
context
realistic
physiological
parameter
values
analyzing
with
inhibitory
or
excitatory
synapses.
We
fails
important
dynamical
features
model,
such
as
self-sustained
oscillations
interneuron
QIF
network.
Furthermore,
model
one,
stimulation
pyramidal
cell
induces
resonant
oscillatory
activity
whose
peak
frequency
amplitude
increase
self-coupling
gain
external
input.
This
may
play
role
enhanced
response
densely
connected
networks
weak
uniform
inputs,
electric
fields
produced
non-invasive
brain
stimulation.