Microstates
are
short,
recurring
electric
field
topographies
over
the
cortex.
The
majority
of
electroencephalogram
(EEG)
signal
variance
is
explained
by
four
representative
topographies,
canonically
known
as
maps
A-D.
Similar
have
been
found
in
wakefulness
and
sleep.
examined
thoroughly
during
wakeful
rest,
but
our
understanding
microstates
other
vigilance
states
limited.
Different
usually
distinguished
EEG
frequency
spectrum
graphoelements,
while
microstate
approach
focuses
on
spatial
distribution
at
each
time
point.
aim
this
study
was
to
analyze
temporal
structure
sequences
Using
information-theoretic
methods,
a
direct
comparison
between
classic
frequency-based
analysis
made
possible.
We
present
an
32
healthy
subjects
sleep
which
we
increase
mean
duration
transition
matrix
relaxation
with
deepening
stages,
pointing
towards
slower
dynamics
Interestingly,
more
than
half
deep
could
not
be
from
simple
Markov
models
can
interpreted
decrease
sequence
complexity.
entropy
rate
decreased
stage,
indicating
less
random,
i.e.
predictable
structure.
Furthermore,
that
occur
periodically
whenever
underlying
has
dominant
frequency.
This
shows
oscillatory
brain
activity
tracked
level,
making
it
possible
distinguish
different
quantitatively.
Interpreting
correlates
functional
networks,
conclude
same
or
very
similar
networks
activated
wakefulness,
their
activation
slowed
down
complex.
Brain Topography,
Год журнала:
2024,
Номер
37(2), С. 169 - 180
Опубликована: Фев. 13, 2024
The
analysis
of
EEG
microstates
for
investigating
rapid
whole-brain
network
dynamics
during
rest
and
tasks
has
become
a
standard
practice
in
the
research
community,
leading
to
substantial
increase
publications
across
various
affective,
cognitive,
social
clinical
neuroscience
domains.
Recognizing
growing
significance
this
analytical
method,
authors
aim
provide
microstate
community
with
comprehensive
discussion
on
methodological
standards,
unresolved
questions,
functional
relevance
microstates.
In
August
2022,
conference
was
hosted
Bern,
Switzerland,
which
brought
together
many
researchers
from
19
countries.
During
conference,
gave
scientific
presentations
engaged
roundtable
discussions
aiming
at
establishing
steps
toward
standardizing
methods.
Encouraged
by
conference's
success,
special
issue
launched
Brain
Topography
compile
current
state-of-the-art
research,
encompassing
advancements,
experimental
findings,
applications.
call
submissions
garnered
48
contributions
worldwide,
spanning
reviews,
meta-analyses,
tutorials,
studies.
Following
rigorous
peer-review
process,
33
papers
were
accepted
whose
findings
we
will
comprehensively
discuss
Editorial.
Communications Biology,
Год журнала:
2024,
Номер
7(1)
Опубликована: Авг. 5, 2024
Consciousness
has
been
proposed
to
be
supported
by
electrophysiological
patterns
poised
at
criticality,
a
dynamical
regime
which
exhibits
adaptive
computational
properties,
maximally
complex
and
divergent
sensitivity
perturbation.
Here,
we
investigate
properties
of
the
resting-state
electroencephalogram
(EEG)
healthy
subjects
undergoing
general
anesthesia
with
propofol,
xenon
or
ketamine.
Importantly,
all
participants
were
unresponsive
under
anesthesia,
while
consciousness
was
retained
only
during
ketamine
(in
form
vivid
dreams),
enabling
an
experimental
dissociation
between
unresponsiveness
unconsciousness.
For
each
condition,
measure
(i)
avalanche
(ii)
chaoticity,
(iii)
criticality-related
metrics,
revealing
that
states
unconsciousness
are
characterized
distancing
from
both
criticality
edge
chaos.
We
then
ask
whether
these
same
predictive
perturbational
complexity
index
(PCI),
TMS-based
shown
remarkably
high
in
detecting
independently
behavior.
successfully
predict
individual
subjects'
PCI
values
considerably
accuracy
EEG
alone.
Our
results
establish
firm
link
provide
further
evidence
is
necessary
condition
for
emergence
consciousness.
An
study
demonstrates
mark
(un)consciousness
able
TMS-derived
(PCI)
adults.
Journal of Neuroscience Methods,
Год журнала:
2025,
Номер
416, С. 110355 - 110355
Опубликована: Янв. 22, 2025
The
neural
mechanisms
underlying
real-time
social
interaction
remain
poorly
understood.
While
hyperscanning
has
emerged
as
a
popular
method
to
better
understand
inter-brain
mechanisms,
methods
underdeveloped,
and
primarily
focused
on
synchronization
(IBS).
We
developed
novel
approach
employing
two-brain
EEG
microstates,
investigate
during
symmetric
asymmetric
interactive
tasks.
Microstates
are
quasi-stable
configurations
of
brain
activity
that
have
been
proposed
represent
basic
building
blocks
for
mental
processing.
Expanding
the
microstate
methodology
dyads
interacting
participants
enables
us
moments
synchronous
activity.
Conventional
microstates
fitted
individuals
were
not
related
different
conditions.
However,
modulated
in
observer-actor
condition,
compared
all
other
conditions
where
had
more
task
demands,
same
trend
was
observed
follower-leader
condition.
This
indicates
differences
resting
state
default-mode
network
interactions
with
Hyperscanning
studies
estimated
IBS
based
functional
connectivity
measures.
localized
connections
often
hard
interpret
larger
scale
when
multiple
across
brains
found
be
important.
Two-brain
offer
an
alternative
evaluate
from
large-scale
global
perspective,
by
quantifying
task-driven
states
between
individuals.
present
using
including
open-source
code,
which
expands
current
hyperscanning-EEG
measure
potentially
identify
both
interaction.
Brain Topography,
Год журнала:
2023,
Номер
37(2), С. 296 - 311
Опубликована: Сен. 26, 2023
EEG
microstate
sequence
analysis
quantifies
properties
of
ongoing
brain
electrical
activity
which
is
known
to
exhibit
complex
dynamics
across
many
time
scales.
In
this
report
we
review
recent
developments
in
quantifying
complexity,
classify
these
approaches
with
regard
different
complexity
concepts,
and
evaluate
excess
entropy
as
a
yet
unexplored
quantity
research.
We
determined
the
quantities
rate,
entropy,
Lempel-Ziv
(LZC),
Hurst
exponents
on
Potts
model
data,
discrete
statistical
mechanics
temperature-controlled
phase
transition.
then
applied
same
techniques
sequences
from
wakefulness
non-REM
sleep
stages
used
first-order
Markov
surrogate
data
determine
scales
contributed
measures.
demonstrate
that
rate
LZC
measure
Kolmogorov
(randomness)
sequences,
whereas
describe
attains
its
maximum
at
intermediate
levels
randomness.
confirmed
equivalence
when
LZ-76
algorithm
used,
result
previously
reported
for
neural
spike
train
(Amigó
et
al.,
Neural
Comput
16:717-736,
https://doi.org/10.1162/089976604322860677
,
2004).
Surrogate
analyses
prove
entropy-based
focus
short-range
temporal
correlations,
include
short
long
Sleep
reveals
deeper
are
accompanied
by
decrease
an
increase
complexity.
Microstate
jump
where
duplicate
states
have
been
removed,
show
higher
randomness,
lower
no
long-range
correlations.
Regarding
practical
use
methods,
suggest
can
be
efficient
estimator
avoids
estimation
joint
entropies,
via
entropies
has
advantage
providing
second
parameter
linear
fit.
conclude
metrics
useful
addition
address
concept
not
covered
existing
algorithms
while
being
actively
explored
other
areas
Journal of Alzheimer s Disease,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 8, 2025
Background
Mild
cognitive
impairment
(MCI)
is
recognized
as
a
condition
that
may
increase
the
risk
of
developing
Alzheimer's
disease
(AD).
Understanding
neural
correlates
MCI
crucial
for
elucidating
its
pathophysiology
and
effective
interventions.
Electroencephalogram
(EEG)
microstates,
reflecting
brain
activity
changes,
have
shown
promise
in
research.
However,
current
approaches
often
lack
comprehensive
characterization
complex
dynamics
associated
with
MCI.
Objective
This
study
aims
to
investigate
neurophysiological
changes
using
set
microstate
features,
including
traditional
temporal
features
entropy
measures.
Methods
Resting-state
EEG
data
were
collected
from
69
patients
healthy
controls
(HC).
Microstate
analysis
was
performed
extract
conventional
(duration,
coverage)
Statistical
analysis,
principal
component
(PCA),
machine
learning
(ML)
techniques
employed
evaluate
patterns
Results
displayed
altered
dynamics,
significantly
longer
coverage
duration
C
but
shorter
Microstates
A,
B,
D
compared
HCs.
PCA
revealed
two
components,
primarily
composed
measures,
explaining
over
75%
variance.
ML
models
achieved
high
accuracy
distinguishing
patterns.
Conclusions
Our
provides
new
insights
into
MCI,
highlighting
potential
microstates
investigating
decline.
Experimental Physiology,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 21, 2025
Abstract
Cardiac
activity
responds
dynamically
to
metabolic
demands
and
neural
regulation.
However,
little
is
known
about
this
process
during
pregnancy.
Reports
show
occasional
fetal–maternal
heart
rate
couplings,
but
it
has
remained
unclear
whether
these
couplings
extend
more
complex
oscillatory
patterns
of
the
rhythm.
We
developed
a
framework
time‐varying
measures
rhythm,
test
presence
co‐varying
in
concurrent
maternal
fetal
(late
pregnancy
dataset,
n
=
10,
labour
12).
These
were
derived
from
first
second‐order
Poincaré
plots,
with
aim
describe
changes
short‐
long‐term
rhythmicity,
also
dynamic
shifts
acceleration
deceleration
rate.
found
episodes
maternal–fetal
cardiac
rhythm
all
explored,
both
datasets
(at
least
90%
dataset
presented
significant
correlation
each
measure,
P
<
0.001),
delays
suggesting
bilateral
interactions
at
different
time
scales.
that
intensify
(test
between
late
vs.
datasets,
0.0015
plot‐derived
measures).
While
most
literature
suggests
breathing
or
contractions,
we
propose
possibility
may
have
signalling
function
context
co‐regulatory
mechanisms
inter‐organ
interactions.
Understanding
visceral
oscillations
utero
enhance
assessment
healthy
development.
Frontiers in Neuroscience,
Год журнала:
2024,
Номер
18
Опубликована: Фев. 2, 2024
Background
The
investigation
of
mindfulness
meditation
practice,
classically
divided
into
focused
attention
(FAM),
and
open
monitoring
(OMM)
styles,
has
seen
a
long
tradition
theoretical,
affective,
neurophysiological
clinical
studies.
In
particular,
the
high
temporal
resolution
magnetoencephalography
(MEG)
or
electroencephalography
(EEG)
been
exploited
to
fill
gap
between
personal
experience
practice
its
neural
correlates.
Mounting
evidence,
in
fact,
shows
that
human
brain
activity
is
highly
dynamic,
transiting
different
states
(microstates).
this
study,
we
aimed
at
exploring
MEG
microstates
source-level
during
FAM,
OMM
resting
state,
as
well
complexity
criticality
dynamic
transitions
microstates.
Methods
Ten
right-handed
Theravada
Buddhist
monks
with
meditative
expertise
minimum
2,265
h
participated
experiment.
data
were
acquired
randomized
block
design
task
(6
min
6
OMM,
each
preceded
followed
by
3
state).
Source
reconstruction
was
performed
using
eLORETA
on
individual
cortical
space,
then
parcellated
according
Human
Connect
Project
atlas.
Microstate
analysis
applied
parcel
level
signals
order
derive
microstate
topographies
indices.
addition,
from
sequences,
Hurst
exponent
Lempel-Ziv
(LZC)
computed.
Results
Our
results
show
coverage
occurrence
specific
are
modulated
either
being
state
performing
style.
values
both
conditions
reduced
respect
value
observed
rest,
LZC
significant
differences
REST,
progressive
increase
REST
FAM
OMM.
Discussion
Importantly,
report
changes
indices
line
state-like
effect
cognitive
performance.
previous
reports,
suggest
change
experienced
paralleled
shift
critical
points
dynamics.
Brain Sciences,
Год журнала:
2024,
Номер
14(5), С. 487 - 487
Опубликована: Май 11, 2024
Exploring
the
spatiotemporal
dynamic
patterns
of
multi-channel
electroencephalography
(EEG)
is
crucial
for
interpreting
dementia
and
related
cognitive
decline.
Spatiotemporal
EEG
can
be
described
through
microstate
analysis,
which
provides
a
discrete
approximation
continuous
electric
field
generated
by
brain
cortex.
Here,
we
propose
novel
indicator,
termed
sequence
non-randomness
index
(MSNRI).
The
essence
method
lies
in
initially
generating
transition
state
space
compression
data
using
analysis.
Following
this,
assess
these
information-based
similarity
results
suggest
that
this
MSNRI
metric
potential
marker
distinguishing
between
health
control
(HC)
frontotemporal
(FTD)
(HC
vs.
FTD:
6.958
5.756,
p
<
0.01),
as
well
HC
populations
with
Alzheimer’s
disease
(AD)
AD:
5.462,
0.001).
Healthy
individuals
exhibit
more
complex
macroscopic
structures
non-random
microstates,
whereas
disorders
lead
to
random
patterns.
Additionally,
extend
proposed
integrating
Complementary
Ensemble
Empirical
Mode
Decomposition
(CEEMD)
explore
microstates
at
specific
frequency
scales.
Moreover,
assessed
effectiveness
innovative
predicting
scores.
demonstrate
incorporation
CEEMD-enhanced
indicators
significantly
improved
prediction
accuracy
Mini-Mental
State
Examination
(MMSE)
scores
(R2
=
0.940).
not
only
aids
exploration
large-scale
neural
changes
but
also
offers
robust
tool
characterizing
dynamics
transitions
their
impact
on
function.