Research Square (Research Square),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Feb. 22, 2024
Abstract
The
present
study
examined
the
effects
of
transcutaneous
auricular
vagus
nerve
stimulation
(taVNS)
on
short-latency
afferent
inhibition
(SAI),
as
indirect
biomarker
cholinergic
system
activation.
24
healthy
adults
underwent
intermittent
taVNS
(30
sec
on/30
off,
30
min)
or
continuous
at
a
frequency
25
Hz
along
with
earlobe
temporary
(15
min
in
15
were
performed
random
order.
efficiency
which
motor
evoked
potential
amplitudes
from
abductor
pollicis
brevismuscle
by
transcranial
magnetic
was
attenuated
preceding
median
conditioning
stimulus
compared
before
taVNS,
immediately
after
and
minutes
taVNS.
Continuous
significantly
increased
SAI
post-stimulation
to
baseline.
A
positive
correlation
(Pearson
coefficient
=
0.563,
p
0.004)
observed
between
baseline
changes
These
results
suggest
that
increases
activity
nervous
system,
evidenced
increase
SAI.
In
particular,
more
pronounced
those
lower
initial
This
provides
fundamental
insight
into
clinical
for
dysfunction.
Perceptual
updating
has
been
proposed
to
rely
upon
evolving
activity
within
a
recurrent,
distributed
thalamocortical
network
whose
interconnections
are
modulated
by
bursts
of
ascending
neuromodulatory
neurotransmitters,
such
as
noradrenaline.
To
test
this
hypothesis
mechanistically,
we
leveraged
combination
pupillometry,
fMRI
and
recurrent
neural
modelling
an
ambiguous
figures
task.
Qualitative
shifts
in
the
perceptual
interpretation
image
were
associated
with
peaks
pupil
diameter,
indirect
readout
phasic
tone.
We
hypothesized
that
increases
tone
led
gain
alteration
so
causally
mediate
switches.
hypothesis,
trained
perform
analogous
categorisation
task,
then
manipulated
RNN
mimic
effect
As
predicted,
observed
earlier
shift
function
heightened
gain.
Leveraging
low-dimensional
dynamics,
developed
two
novel
predictions:
switches
should
co-occur
brain
state
velocity
flattened
energy
landscape
dynamics.
used
dimensionality-reduced
summaries
whole-brain
dynamics
independently
confirm
each
these
predictions.
These
results
support
role
system
large-scale
reconfigurations
abrupt
changes
perception.
Signatures
of
consciousness
are
found
in
spectral
and
temporal
properties
neuronal
activity.
Among
these,
spatiotemporal
complexity
after
a
perturbation
has
recently
emerged
as
robust
metric
to
infer
levels
consciousness.
Perturbation
paradigms
remain,
however,
difficult
perform
routinely.
To
discover
alternative
metrics
we
systematically
explore
brain
stimulation
resting-state
activity
digital
twin
model.
We
find
that
perturbational
only
occurs
when
the
model
operates
within
specific
dynamical
regime,
which
spontaneous
produces
large
degree
functional
network
reorganizations
referred
being
fluid.
The
regime
high
fluidity
is
characterized
by
small
battery
drawn
from
systems
theory
predicts
impact
altering
drugs
(Xenon,
Propofol
Ketamine).
validate
predictions
cohort
15
subjects
at
various
stages
demonstrate
their
agreement
with
previously
reported
complexity,
but
more
accessible
paradigm.
Beyond
facilitation
clinical
use,
highlights
dynamics
support
emergence
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Jan. 30, 2024
Abstract
Despite
their
widespread
use,
we
have
limited
knowledge
of
the
mechanisms
by
which
sedatives
mediate
effects
on
brain-wide
networks.
This
is,
in
part,
due
to
technical
challenge
observing
activity
across
large
populations
neurons
normal
and
sedated
brains.
In
this
study,
examined
sedative
dexmedetomidine,
its
antagonist
atipamezole,
spontaneous
brain
dynamics
auditory
processing
zebrafish
larvae.
Our
brain-wide,
cellular-resolution
calcium
imaging
reveals,
for
first
time,
regions
involved
these
network-scale
individual
that
are
affected
within
those
regions.
Further
analysis
reveals
a
variety
dynamic
changes
at
baseline,
including
marked
reductions
activity,
correlation,
variance.
The
variance
represent
“quieter”
state
during
sedation,
an
effect
causes
highly
correlated
evoked
system
stand
out
more
than
it
does
un-sedated
We
also
observe
reduction
response
latencies
suggesting
removal
leaves
core
pathway
free
impingement
from
other
non-auditory
information.
Finally,
describe
less
network
with
higher
energy
barrier
lower
probability
transitions
sedation.
total,
our
shows
sedation
leads
quieter,
stable,
brain,
against
background,
responses
become
sharper
prominent.
Significance
Statement
Animals’
states
constantly
fluctuate
environment
context,
leading
perception
behavioral
choices.
Alterations
perception,
sensorimotor
gating,
selection
hallmarks
numerous
neuropsychiatric
disorders,
but
circuit-
network-level
underpinnings
alterations
poorly
understood.
Pharmacological
alters
responsiveness
provides
controlled
repeatable
manipulation
studying
underlying
circuitry.
Here,
show
larval
dexmedetomidine
reduces
locomotion
portions
behavior
intact.
computationally
model
levels
neurons,
local
circuits,
networks
lead
altered
sensory
Research Square (Research Square),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Feb. 22, 2024
Abstract
The
present
study
examined
the
effects
of
transcutaneous
auricular
vagus
nerve
stimulation
(taVNS)
on
short-latency
afferent
inhibition
(SAI),
as
indirect
biomarker
cholinergic
system
activation.
24
healthy
adults
underwent
intermittent
taVNS
(30
sec
on/30
off,
30
min)
or
continuous
at
a
frequency
25
Hz
along
with
earlobe
temporary
(15
min
in
15
were
performed
random
order.
efficiency
which
motor
evoked
potential
amplitudes
from
abductor
pollicis
brevismuscle
by
transcranial
magnetic
was
attenuated
preceding
median
conditioning
stimulus
compared
before
taVNS,
immediately
after
and
minutes
taVNS.
Continuous
significantly
increased
SAI
post-stimulation
to
baseline.
A
positive
correlation
(Pearson
coefficient
=
0.563,
p
0.004)
observed
between
baseline
changes
These
results
suggest
that
increases
activity
nervous
system,
evidenced
increase
SAI.
In
particular,
more
pronounced
those
lower
initial
This
provides
fundamental
insight
into
clinical
for
dysfunction.
