Unified
structural
equation
modeling
(uSEM)
implemented
in
the
Group
Iterative
Multiple
Model
Estimation
(GIMME)
framework
has
recently
been
widely
used
for
characterizing
within-person
network
dynamics
of
behavioral
and
functional
neuroimaging
variables.
Previous
studies
have
established
that
GIMME
accurately
recovers
presence
relations
between
However,
recovery
relation
directionality
is
less
consistent,
which
concerning
given
importance
estimates
many
research
questions.
There
evidence
strong
autoregressive
may
aid
indirect
a
novel
version
allowing
multiple
solutions
could
improve
when
such
are
weak,
but
it
remains
unclear
how
these
strategies
perform
under
range
study
conditions.
Using
comprehensive
simulations
varied
strength
among
other
factors,
this
evaluated
two
search
strategies:
1)
estimating
by
default
null
model
(GIMME-AR),
2)
generating
solution
paths
(GIMME-MS).
Both
recovered
best
–
were
roughly
equivalent
performance
(e.g.,
β
=
.60).
When
they
weak
(β
<=
.10),
GIMME-MS
displayed
an
advantage,
although
overall
was
modest.
Analyses
empirical
data
characteristically
(resting
state
fMRI)
versus
(daily
diary)
mirrored
simulation
results
confirmed
can
disagree
on
weak.
Findings
important
implications
psychological
applications
uSEM/GIMME
suggest
specific
scenarios
researchers
might
or
not
be
confident
results.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: April 11, 2023
SUMMARY
Myelin
is
essential
for
rapid
nerve
signaling
and
increasingly
found
to
play
important
roles
in
learning
diverse
diseases
of
the
CNS.
Morphological
parameters
myelin
such
as
sheath
length
thickness
are
regulated
by
neuronal
activity
can
precisely
tune
conduction
velocity,
but
mechanisms
controlling
morphology
poorly
understood.
Local
calcium
has
been
observed
nascent
sheaths
be
modulated
activity.
However,
role
formation
remodeling
unknown.
Here,
we
used
genetic
tools
attenuate
oligodendrocyte
during
active
myelination
developing
mouse
Surprisingly,
that
attenuation
did
not
grossly
affect
number
myelinated
axons
or
thickness.
Instead,
caused
striking
defects
resulting
shorter,
dysmorphic
sheaths.
Mechanistically,
reduced
actin
filaments
oligodendrocytes,
an
intact
cytoskeleton
was
necessary
sufficient
achieve
accurate
morphology.
Together,
our
work
reveals
a
novel
cellular
mechanism
required
CNS
provides
mechanistic
insight
into
how
oligodendrocytes
may
respond
sculpt
throughout
nervous
system.
Frontiers in Neuroscience,
Journal Year:
2021,
Volume and Issue:
15
Published: July 16, 2021
Despite
advancements
in
the
development
of
cell-based
in-vitro
neuronal
network
models,
lack
appropriate
computational
tools
limits
their
analyses.
Methods
aimed
at
deciphering
effective
connections
between
neurons
from
extracellular
spike
recordings
would
increase
utility
vitro
local
neural
circuits,
especially
for
studies
human
and
disease
based
on
induced
pluripotent
stem
cells
(hiPSC).
Current
techniques
allow
statistical
inference
functional
couplings
but
are
fundamentally
unable
to
correctly
identify
indirect
apparent
neurons,
generating
redundant
maps
with
limited
ability
model
causal
dynamics
network.
In
this
paper,
we
describe
a
novel
mathematically
rigorous,
model-free
method
map
effective—direct
causal—connectivity
networks
multi-electrode
array
data.
The
algorithm
uses
combination
deterministic
indicators
which,
first,
enables
identification
all
existing
links
then
reconstructs
directed
connection
diagram
via
super-selective
rule
enabling
highly
accurate
classification
direct,
indirect,
links.
Our
can
be
generally
applied
characterization
any
networks.
Here,
show
that,
given
its
accuracy,
it
offer
important
insights
into
hiPSC-derived
cultures.
arXiv (Cornell University),
Journal Year:
2020,
Volume and Issue:
unknown
Published: Jan. 1, 2020
Primates
display
a
marked
ability
to
learn
habits
in
uncertain
and
dynamic
environments.
The
associated
perceptions
actions
of
such
engage
distributed
neural
circuits.
Yet,
precisely
how
circuits
support
the
computations
necessary
for
habit
learning
remain
far
from
understood.
Here
we
construct
formal
theory
network
energetics
account
changes
brain
state
produce
sequential
behavior.
We
exercise
context
multi-unit
recordings
spanning
caudate
nucleus,
prefrontal
cortex,
frontal
eyefields
female
macaque
monkeys
engaged
60-180
sessions
free
scan
task
that
induces
motor
habits.
relies
on
determination
effective
connectivity
between
recording
channels,
stipulation
is
taken
be
trial-specific
firing
rate
across
those
channels.
then
predicts
much
energy
will
required
transition
one
into
another,
given
constraint
activity
can
spread
solely
through
connections.
Consistent
with
theory's
predictions,
observed
smaller
requirements
transitions
more
similar
complex
trial
saccade
patterns,
characterized
by
less
entropic
selection
patterns.
Using
virtual
lesioning
approach,
demonstrate
resilience
relationships
minimum
control
behavior
significant
disruptions
inferred
connectivity.
Our
theoretically
principled
approach
study
paves
way
future
efforts
examining
arises
changing
patterns
circuitry.
Unified
structural
equation
modeling
(uSEM)
implemented
in
the
Group
Iterative
Multiple
Model
Estimation
(GIMME)
framework
has
recently
been
widely
used
for
characterizing
within-person
network
dynamics
of
behavioral
and
functional
neuroimaging
variables.
Previous
studies
have
established
that
GIMME
accurately
recovers
presence
relations
between
However,
recovery
relation
directionality
is
less
consistent,
which
concerning
given
importance
estimates
many
research
questions.
There
evidence
strong
autoregressive
may
aid
indirect
a
novel
version
allowing
multiple
solutions
could
improve
when
such
are
weak,
but
it
remains
unclear
how
these
strategies
perform
under
range
study
conditions.
Using
comprehensive
simulations
varied
strength
among
other
factors,
this
evaluated
two
search
strategies:
1)
estimating
by
default
null
model
(GIMME-AR),
2)
generating
solution
paths
(GIMME-MS).
Both
recovered
best
–
were
roughly
equivalent
performance
(e.g.,
β
=
.60).
When
they
weak
(β
<=
.10),
GIMME-MS
displayed
an
advantage,
although
overall
was
modest.
Analyses
empirical
data
characteristically
(resting
state
fMRI)
versus
(daily
diary)
mirrored
simulation
results
confirmed
can
disagree
on
weak.
Findings
important
implications
psychological
applications
uSEM/GIMME
suggest
specific
scenarios
researchers
might
or
not
be
confident
results.