bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2022,
Volume and Issue:
unknown
Published: Jan. 27, 2022
ABSTRACT
Recent
work
identified
single
time
points
(“events”)
of
high
regional
cofluctuation
in
functional
Magnetic
Resonance
Imaging
(fMRI)
which
contain
more
large-scale
brain
network
information
than
other,
low
points.
This
suggested
that
events
might
be
a
discrete,
temporally
sparse
signal
drives
connectivity
(FC)
over
the
timeseries.
However,
different,
not
yet
explored
possibility
is
differences
between
are
driven
by
sampling
variability
on
constant,
static,
noisy
signal.
Using
combination
real
and
simulated
data,
we
examined
relationship
structure
asked
if
this
was
unique,
or
it
could
arise
from
alone.
First,
show
discrete
–
there
gradually
increasing
cofluctuation;
∼50%
samples
very
strong
structure.
Second,
using
simulations
predicted
static
FC.
Finally,
randomly
selected
can
capture
about
as
well
events,
largely
because
their
temporal
spacing.
Together,
these
results
suggest
that,
while
exhibit
particularly
representations
FC,
little
evidence
unique
timepoints
drive
FC
Instead,
parsimonious
explanation
for
data
but
noisy,
HIGHLIGHTS
Past
BOLD
“events”
fMRI
connectivity,
Here,
were
both
stationary
null
model
to
test
In
>50%
modularity
similarity
time-
averaged
Stationary
models
with
similar
behavior
Events
may
transient
driver
rather
an
expected
outcome
it.
Network Neuroscience,
Journal Year:
2021,
Volume and Issue:
5(2), P. 405 - 433
Published: Jan. 1, 2021
Abstract
Functional
connectivity
(FC)
describes
the
statistical
dependence
between
neuronal
populations
or
brain
regions
in
resting-state
fMRI
studies
and
is
commonly
estimated
as
Pearson
correlation
of
time
courses.
Clustering
community
detection
reveals
densely
coupled
sets
constituting
networks
functional
systems.
These
systems
manifest
most
clearly
when
FC
sampled
over
longer
epochs
but
appear
to
fluctuate
on
shorter
timescales.
Here,
we
propose
a
new
approach
reveal
temporal
fluctuations
series.
Unwrapping
signal
correlations
yields
pairwise
co-fluctuation
series,
one
for
each
node
pair
edge,
allows
tracking
fine-scale
dynamics
across
network.
Co-fluctuations
partition
network,
at
step,
into
exactly
two
communities.
Sampled
time,
overlay
these
bipartitions,
binary
decomposition
original
very
closely
approximates
connectivity.
Bipartitions
exhibit
characteristic
spatiotemporal
patterns
that
are
reproducible
participants
imaging
runs,
capture
individual
differences,
disclose
expression
Our
findings
document
transiently
intermittently,
results
from
many
variable
instances
system
expression.
Potential
applications
this
set
discussed.
Network Neuroscience,
Journal Year:
2021,
Volume and Issue:
unknown, P. 1 - 28
Published: Aug. 13, 2021
Abstract
Network
models
describe
the
brain
as
sets
of
nodes
and
edges
that
represent
its
distributed
organization.
So
far,
most
discoveries
in
network
neuroscience
have
prioritized
insights
highlight
distinct
groupings
specialized
functional
contributions
nodes.
Importantly,
these
are
determined
expressed
by
web
their
interrelationships,
formed
edges.
Here,
we
underscore
important
made
for
understanding
Different
types
different
relationships,
including
connectivity
similarity
among
Adopting
a
specific
definition
can
fundamentally
alter
how
analyze
interpret
network.
Furthermore,
associate
into
collectives
higher
order
arrangements,
time
series,
form
edge
communities
provide
topology
complementary
to
traditional
node-centric
perspective.
Focusing
on
edges,
or
dynamic
information
they
provide,
discloses
previously
underappreciated
aspects
structural
Communications Biology,
Journal Year:
2022,
Volume and Issue:
5(1)
Published: June 2, 2022
The
relationship
between
structural
and
functional
connectivity
in
the
brain
is
a
key
question
systems
neuroscience.
Modern
accounts
assume
single
global
structure-function
that
persists
over
time.
Here
we
study
coupling
from
dynamic
perspective,
show
it
regionally
heterogeneous.
We
use
temporal
unwrapping
procedure
to
identify
moment-to-moment
co-fluctuations
neural
activity,
reconstruct
time-resolved
patterns.
find
patterns
of
are
region-specific.
observe
stable
unimodal
transmodal
cortex,
intermediate
regions,
particularly
insular
cortex
(salience
network)
frontal
eye
fields
(dorsal
attention
network).
Finally,
variability
region's
related
distribution
its
connection
lengths.
Collectively,
our
findings
provide
way
relationships
perspective.
NeuroImage,
Journal Year:
2022,
Volume and Issue:
252, P. 118993 - 118993
Published: Feb. 19, 2022
Resting-state
functional
connectivity
is
typically
modeled
as
the
correlation
structure
of
whole-brain
regional
activity.
It
studied
widely,
both
to
gain
insight
into
brain's
intrinsic
organization
but
also
develop
markers
sensitive
changes
in
an
individual's
cognitive,
clinical,
and
developmental
state.
Despite
this,
origins
drivers
connectivity,
especially
at
level
densely
sampled
individuals,
remain
elusive.
Here,
we
leverage
novel
methodology
decompose
its
precise
framewise
contributions.
Using
two
dense
sampling
datasets,
investigate
individualized
focusing
specifically
on
role
brain
network
"events"
-
short-lived
peaked
patterns
high-amplitude
cofluctuations.
a
statistical
test
identify
events
empirical
recordings.
We
show
that
cofluctuation
expressed
during
are
repeated
across
multiple
scans
same
individual
represent
idiosyncratic
variants
template
group
level.
Lastly,
propose
simple
model
based
event
cofluctuations,
demonstrating
group-averaged
cofluctuations
suboptimal
for
explaining
participant-specific
connectivity.
Our
work
complements
recent
studies
implicating
brief
instants
primary
static,
extends
those
studies,
individualized,
positing
dynamic
basis
Trends in Cognitive Sciences,
Journal Year:
2023,
Volume and Issue:
27(11), P. 1068 - 1084
Published: Sept. 15, 2023
Network
neuroscience
has
emphasized
the
connectional
properties
of
neural
elements
-
cells,
populations,
and
regions.
This
come
at
expense
anatomical
functional
connections
that
link
these
to
one
another.
A
new
perspective
namely
emphasizes
'edges'
may
prove
fruitful
in
addressing
outstanding
questions
network
neuroscience.
We
highlight
recently
proposed
'edge-centric'
method
review
its
current
applications,
merits,
limitations.
also
seek
establish
conceptual
mathematical
links
between
this
previously
approaches
science
neuroimaging
literature.
conclude
by
presenting
several
avenues
for
future
work
extend
refine
existing
edge-centric
analysis.
NeuroImage,
Journal Year:
2022,
Volume and Issue:
260, P. 119476 - 119476
Published: July 14, 2022
Recent
work
identified
single
time
points
("events")
of
high
regional
cofluctuation
in
functional
Magnetic
Resonance
Imaging
(fMRI)
which
contain
more
large-scale
brain
network
information
than
other,
low
points.
This
suggested
that
events
might
be
a
discrete,
temporally
sparse
signal
drives
connectivity
(FC)
over
the
timeseries.
However,
different,
not
yet
explored
possibility
is
differences
between
are
driven
by
sampling
variability
on
constant,
static,
noisy
signal.
Using
combination
real
and
simulated
data,
we
examined
relationship
structure
asked
if
this
was
unique,
or
it
could
arise
from
alone.
First,
show
discrete
-
there
gradually
increasing
cofluctuation;
∼50%
samples
very
strong
structure.
Second,
using
simulations
predicted
static
FC.
Finally,
randomly
selected
can
capture
about
as
well
events,
largely
because
their
temporal
spacing.
Together,
these
results
suggest
that,
while
exhibit
particularly
representations
FC,
little
evidence
unique
timepoints
drive
FC
Instead,
parsimonious
explanation
for
data
but
noisy,
NeuroImage,
Journal Year:
2022,
Volume and Issue:
263, P. 119591 - 119591
Published: Aug. 27, 2022
The
interaction
between
brain
regions
changes
over
time,
which
can
be
characterized
using
time-varying
functional
connectivity
(tvFC).
common
approach
to
estimate
tvFC
uses
sliding
windows
and
offers
limited
temporal
resolution.
An
alternative
method
is
use
the
recently
proposed
edge-centric
approach,
enables
tracking
of
moment-to-moment
in
co-fluctuation
patterns
pairs
regions.
Here,
we
first
examined
dynamic
features
edge
time
series
compared
them
those
window
(sw-tvFC).
Then,
used
compare
subjects
with
autism
spectrum
disorder
(ASD)
healthy
controls
(CN).
Our
results
indicate
that
relative
sw-tvFC,
captured
rapid
bursty
network-level
fluctuations
synchronize
across
during
movie-watching.
from
second
part
study
suggested
magnitude
peak
amplitude
collective
co-fluctuations
(estimated
as
root
sum
square
(RSS)
series)
similar
CN
ASD.
However,
trough-to-trough
duration
RSS
signal
greater
ASD,
CN.
Furthermore,
an
edge-wise
comparison
high-amplitude
showed
within-network
edges
exhibited
findings
suggest
by
provide
details
about
disruption
dynamics
could
potentially
developing
new
biomarkers
mental
disorders.
NeuroImage Clinical,
Journal Year:
2022,
Volume and Issue:
35, P. 103055 - 103055
Published: Jan. 1, 2022
Most
neuroimaging
studies
of
post-stroke
recovery
rely
on
analyses
derived
from
standard
node-centric
functional
connectivity
to
map
the
distributed
effects
in
stroke
patients.
Here,
given
importance
nonlocal
and
diffuse
damage,
we
use
an
edge-centric
approach
order
provide
alternative
description
this
disorder.
These
techniques
allow
for
rendering
metrics
such
as
normalized
entropy,
which
describes
diversity
edge
communities
at
each
node.
Moreover,
enables
identification
high
amplitude
co-fluctuations
fMRI
time
series.
We
found
that
entropy
is
associated
with
lesion
severity
continually
increases
across
patients'
recovery.
Furthermore,
not
only
relate
but
are
also
level
The
current
study
first
application
a
clinical
population
longitudinal
dataset
demonstrates
how
different
perspective
data
analysis
can
further
characterize
topographic
modulations
brain
dynamics.
Communications Biology,
Journal Year:
2024,
Volume and Issue:
7(1)
Published: Jan. 24, 2024
Abstract
Previous
studies
have
adopted
an
edge-centric
framework
to
study
fine-scale
network
dynamics
in
human
fMRI.
To
date,
however,
no
applied
this
data
collected
from
model
organisms.
Here,
we
analyze
structural
and
functional
imaging
lightly
anesthetized
mice
through
lens.
We
find
evidence
of
“bursty”
events
-
brief
periods
high-amplitude
connectivity.
Further,
show
that
on
a
per-frame
basis
best
explain
static
FC
can
be
divided
into
series
hierarchically-related
clusters.
The
co-fluctuation
patterns
associated
with
each
cluster
centroid
link
distinct
anatomical
areas
largely
adhere
the
boundaries
algorithmically
detected
brain
systems.
then
investigate
connectivity
undergirding
patterns.
induce
modular
bipartitions
inter-areal
axonal
projections.
Finally,
replicate
these
same
findings
dataset.
In
summary,
report
recapitulates
organism
many
phenomena
observed
previously
analyses
data.
However,
unlike
subjects,
murine
nervous
system
is
amenable
invasive
experimental
perturbations.
Thus,
sets
stage
for
future
investigation
causal
origins
co-fluctuations.
Moreover,
cross-species
consistency
reported
enhances
likelihood
translation.