bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2021,
Volume and Issue:
unknown
Published: April 18, 2021
Abstract
Brain
activity
flow
models
estimate
the
movement
of
task-evoked
over
brain
connections
to
help
explain
network-generated
task
functionality.
Activity
have
been
shown
accurately
generate
activations
across
a
wide
variety
regions
and
conditions.
However,
these
had
limited
explanatory
power,
given
known
issues
with
causal
interpretations
standard
functional
connectivity
measures
used
parameterize
models.
We
show
here
that
functional/effective
(FC)
grounded
in
principles
facilitate
mechanistic
interpretation
progress
from
simple
complex
FC
measures,
each
adding
algorithmic
details
reflecting
principles.
This
reflects
many
neuroscientists’
preference
for
reduced
measure
complexity
(to
minimize
assumptions,
compute
time,
fully
comprehend
easily
communicate
methodological
details),
which
potentially
trades
off
validity.
start
Pearson
correlation
(the
current
field
standard)
remain
maximally
relevant
field,
estimating
validity
range
using
simulations
empirical
fMRI
data.
Finally,
we
apply
causal-FC-based
modeling
dorsolateral
prefrontal
cortex
region
(DLPFC),
demonstrating
distributed
network
mechanisms
contributing
its
strong
activation
during
working
memory
task.
Notably,
this
model
is
able
account
DLPFC
effects
traditionally
thought
rely
primarily
on
within-region
(i.e.,
not
distributed)
recurrent
processes.
Together,
results
reveal
promise
parameterizing
methods
identify
underlying
cognitive
computations
human
brain.
Highlights
-
provide
insight
into
how
neurocognitive
are
generated
interactions.
Functional
statistical
Mechanistic
predict
neural
tasks.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Sept. 17, 2023
Abstract
Functional
connectivity
(FC)
has
been
invaluable
for
understanding
the
brain’s
communication
network,
with
strong
potential
enhanced
FC
approaches
to
yield
additional
insights.
Unlike
fMRI
field-standard
method
of
pairwise
correlation,
theory
suggests
that
partial
correlation
can
estimate
without
confounded
and
indirect
connections.
However,
also
display
low
repeat
reliability,
impairing
accuracy
individual
estimates.
We
hypothesized
reliability
would
be
increased
by
adding
regularization,
which
reduce
overfitting
noise
in
regression-based
like
correlation.
therefore
tested
several
regularized
alternatives
–
graphical
lasso,
ridge,
principal
component
regression
against
unregularized
applying
them
empirical
resting-state
simulated
data.
As
hypothesized,
regularization
vastly
improved
quantified
using
between-session
similarity
intraclass
This
then
granted
substantially
more
accurate
estimates
when
validated
structural
(empirical
data)
ground
truth
networks
(simulations).
Graphical
lasso
showed
especially
high
among
approaches,
seemingly
maintaining
valid
underlying
network
structures.
additionally
found
robust
levels,
data
quantity,
subject
motion
common
error
sources.
Lastly,
we
demonstrated
effectively
predict
task
activations
differences
behavior,
further
establishing
its
external
validity,
ability
characterize
task-related
functionality.
recommend
or
similar
methods
calculating
FC,
as
they
unconfounded
than
while
overcoming
poor
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: June 29, 2023
During
cognitive
task
learning,
neural
representations
must
be
rapidly
constructed
for
novel
performance,
then
optimized
robust
practiced
performance.
How
the
geometry
of
changes
to
enable
this
transition
from
performance
remains
unknown.
We
hypothesized
that
practice
involves
a
shift
compositional
(task-general
activity
patterns
can
flexibly
reused
across
tasks)
conjunctive
(task-specific
specialized
current
task).
Functional
MRI
during
learning
multiple
complex
tasks
substantiated
dynamic
representations,
which
was
associated
with
reduced
cross-task
interference
(via
pattern
separation)
and
behavioral
improvement.
Further,
we
found
conjunctions
originated
in
subcortex
(hippocampus
cerebellum)
slowly
spread
cortex,
extending
memory
systems
theories
encompass
representation
learning.
The
formation
hence
serves
as
computational
signature
reflecting
cortical-subcortical
dynamics
optimize
human
brain.
NeuroImage,
Journal Year:
2023,
Volume and Issue:
278, P. 120300 - 120300
Published: July 29, 2023
Brain
activity
flow
models
estimate
the
movement
of
task-evoked
over
brain
connections
to
help
explain
network-generated
task
functionality.
Activity
have
been
shown
accurately
generate
activations
across
a
wide
variety
regions
and
conditions.
However,
these
had
limited
explanatory
power,
given
known
issues
with
causal
interpretations
standard
functional
connectivity
measures
used
parameterize
models.
We
show
here
that
functional/effective
(FC)
grounded
in
principles
facilitate
mechanistic
interpretation
progress
from
simple
complex
FC
measures,
each
adding
algorithmic
details
reflecting
principles.
This
reflects
many
neuroscientists'
preference
for
reduced
measure
complexity
(to
minimize
assumptions,
compute
time,
fully
comprehend
easily
communicate
methodological
details),
which
potentially
trades
off
validity.
start
Pearson
correlation
(the
current
field
standard)
remain
maximally
relevant
field,
estimating
validity
range
using
simulations
empirical
fMRI
data.
Finally,
we
apply
causal-FC-based
modeling
dorsolateral
prefrontal
cortex
region
(DLPFC),
demonstrating
distributed
network
mechanisms
contributing
its
strong
activation
during
working
memory
task.
Notably,
this
model
is
able
account
DLPFC
effects
traditionally
thought
rely
primarily
on
within-region
(i.e.,
not
distributed)
recurrent
processes.
Together,
results
reveal
promise
parameterizing
methods
identify
underlying
cognitive
computations
human
brain.
PLoS Computational Biology,
Journal Year:
2025,
Volume and Issue:
21(3), P. e1012870 - e1012870
Published: March 7, 2025
Understanding
the
large-scale
information
processing
that
underlies
complex
human
cognition
is
central
goal
of
cognitive
neuroscience.
While
emerging
activity
flow
models
demonstrate
task
transferred
by
interregional
functional
or
structural
connectivity,
graph-theory-based
typically
assume
neural
communication
occurs
via
shortest
path
brain
networks.
However,
whether
optimal
route
for
empirical
transmission
remains
unclear.
Based
on
a
mapping
framework,
we
found
performance
prediction
with
was
significantly
lower
than
direct
path.
The
routing
superior
to
other
network
strategies,
including
search
information,
ensembles,
and
navigation.
Intriguingly,
outperformed
in
when
physical
distance
constraint
asymmetric
contribution
were
simultaneously
considered.
This
study
not
only
challenges
assumption
through
but
also
suggests
constrained
spatial
embedding
network.
NeuroImage,
Journal Year:
2023,
Volume and Issue:
276, P. 120213 - 120213
Published: June 1, 2023
Predictions
of
task-based
functional
magnetic
resonance
imaging
(fMRI)
from
task-free
resting-state
(rs)
fMRI
have
gained
popularity
over
the
past
decade.
This
method
holds
a
great
promise
for
studying
individual
variability
in
brain
function
without
need
to
perform
highly
demanding
tasks.
However,
order
be
broadly
used,
prediction
models
must
prove
generalize
beyond
dataset
they
were
trained
on.
In
this
work,
we
test
generalizability
task-fMRI
rs-fMRI
across
sites,
MRI
vendors
and
age-groups.
Moreover,
investigate
data
requirements
successful
prediction.
We
use
Human
Connectome
Project
(HCP)
explore
how
different
combinations
training
sample
sizes
number
datapoints
affect
success
various
cognitive
then
apply
on
HCP
predict
activations
site,
vendor
(Phillips
vs.
Siemens
scanners)
age
group
(children
HCP-development
project).
demonstrate
that,
depending
task,
set
approximately
20
participants
with
100
timepoints
each
yields
largest
gain
model
performance.
Nevertheless,
further
increasing
size
results
significantly
improved
predictions,
until
reaching
450-600
800-1000
timepoints.
Overall,
influences
more
than
size.
show
that
adequate
amounts
successfully
groups
provide
predictions
are
both
accurate
individual-specific.
These
findings
suggest
large-scale
publicly
available
datasets
may
utilized
study
smaller,
unique
samples.
NeuroImage,
Journal Year:
2024,
Volume and Issue:
297, P. 120761 - 120761
Published: July 27, 2024
Flexible
cognitive
functions,
such
as
working
memory
(WM),
usually
require
a
balance
between
localized
and
distributed
information
processing.
However,
it
is
challenging
to
uncover
how
local
processing
specifically
contributes
task-induced
activity
in
region.
Although
the
recently
proposed
flow
mapping
approach
revealed
relative
contribution
of
processing,
few
studies
have
explored
adaptive
plastic
changes
that
underlie
manipulation.
In
this
study,
we
recruited
51
healthy
volunteers
(31
females)
investigated
brain
activation
frontoparietal
systems
was
modulated
by
WM
load
training.
While
both
executive
control
network
(ECN)
dorsal
attention
(DAN)
increased
linearly
with
at
baseline,
showed
linear
response
only
DAN,
which
prominently
attributed
within-network
flow.
Importantly,
training
selectively
induced
an
increase
ECN
also
load,
were
predominantly
due
between-network
Furthermore,
demonstrated
causal
effect
prediction
through
manipulation
on
connectivity
activity.
contrast
classic
estimation,
our
findings
suggest
provides
unique
insights
into
neural
under
This
study
offers
new
methodological
framework
for
exploring
integration
versus
segregation
underlying
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Nov. 5, 2023
Abstract
Understanding
large-scale
brain
dynamics
is
a
grand
challenge
in
neuroscience.
We
propose
functional
connectome-based
Hopfield
Neural
Networks
(fcHNNs)
as
model
of
macro-scale
dynamics,
arising
from
recurrent
activity
flow
among
regions.
An
fcHNN
neither
optimized
to
mimic
certain
characteristics,
nor
trained
solve
specific
tasks;
its
weights
are
simply
initialized
with
empirical
connectivity
values.
In
the
framework,
understood
relation
so-called
attractor
states,
i.e.
neurobiologically
meaningful
low-energy
configurations.
Analyses
7
distinct
datasets
demonstrate
that
fcHNNs
can
accurately
reconstruct
and
predict
under
wide
range
conditions,
including
resting
task
states
disorders.
By
establishing
mechanistic
link
between
activity,
offer
simple
interpretable
computational
alternative
conventional
descriptive
analyses
function.
Being
generative
yield
insights
hold
potential
uncover
novel
treatment
targets.
Key
Points
present
yet
powerful
phenomenological
for
The
uses
artificial
neural
network
(fcHNN)
architecture
compute
“activity
flow”
through
regions
several
characteristics
state
conceptualize
both
task-induced
pathological
changes
non-linear
alteration
these
Our
approach
validated
using
neuroimaging
data
seven
studies
offers
function