The
role
of
the
parietal
cortex
in
perceptual
awareness
and
resolving
ambiguity
is
unsettled.
Early
influential
TMS
studies
have
revealed
differences
conscious
perception
following
stimulation,
fuelling
notion
that
causally
contributes
to
ambiguity.
However,
central
this
conclusion
reliability
method
employed.
Several
prior
opposing
effects,
such
as
shortening,
lengthening,
or
no
effect
on
multistable
transitions
stimulation.
Here
we
addressed
continuous
theta-burst
stimulation
(cTBS)
bistable
stimuli.
We
conducted
three
cTBS
experiments
were
matched
terms
stimuli,
protocol,
target
site,
used
a
higher
number
participants.
None
our
replicated
results.
only
experiment
using
individual
functional
localizers
led
weak
while
two
others
null
Individual
variability
motor
did
not
predict
effects.
In
view
recent
reports
highly
variable
effects
over
cortex,
results
suggest
particularly
unreliable
modulating
when
applied
cortex.
Cell Reports,
Год журнала:
2024,
Номер
43(3), С. 113952 - 113952
Опубликована: Март 1, 2024
When
exposed
to
sensory
sequences,
do
macaque
monkeys
spontaneously
form
abstract
internal
models
that
generalize
novel
experiences?
Here,
we
show
neuronal
populations
in
ventrolateral
prefrontal
cortex
jointly
encode
visual
sequences
by
separate
codes
for
the
specific
pictures
presented
and
their
sequential
structure.
We
recorded
neurons
while
passively
viewed
sequence
mismatches
local-global
paradigm.
Even
without
any
overt
task
or
response
requirements,
representations
of
structure,
serial
order,
image
identity
within
distinct
but
superimposed
subspaces.
Representations
structure
rapidly
update
following
single
exposure
a
mismatch
sequence,
represent
different
complexity.
Finally,
those
across
same
repetition
comprising
images.
These
results
suggest
rich
reflecting
both
content-specific
information.
Proceedings of the National Academy of Sciences,
Год журнала:
2024,
Номер
121(42)
Опубликована: Окт. 7, 2024
Predictive
coding
is
a
fundamental
function
of
the
cortex.
The
predictive
routing
model
proposes
neurophysiological
implementation
for
coding.
Predictions
are
fed
back
from
deep-layer
cortex
via
alpha/beta
(8
to
30
Hz)
oscillations.
They
inhibit
gamma
(40
100
and
spiking
that
feed
sensory
inputs
forward.
Unpredicted
arrive
in
circuits
unprepared
by
alpha/beta,
resulting
enhanced
spiking.
To
test
its
role
consciousness,
we
collected
data
intracranial
recordings
macaque
monkeys
during
passive
presentation
auditory
oddballs
before
after
propofol-mediated
loss
consciousness
(LOC).
In
line
with
model,
oscillations
awake
state
served
processing
predictable
stimuli.
Propofol-mediated
LOC
eliminated
modulation
stimulus
coherence
between
frontal
areas.
As
result,
oddball
stimuli
evoked
power,
late
period
(>200
ms
onset)
spiking,
superficial
layer
sinks
also
resulted
diminished
decodability
pattern-level
prediction
error
signals
higher-order
Therefore,
was
disinhibited
LOC.
However,
despite
these
feedforward
responses
cortex,
there
differential
This
may
be
consequence
within-area
interareal
spike-field
coupling
frequency
bands.
These
results
provide
strong
constraints
current
theories
consciousness.
Human
high-order
thalamic
nuclei
activity
is
known
to
closely
correlate
with
conscious
states.
However,
it
not
clear
how
those
and
thalamocortical
interactions
directly
contribute
the
transient
process
of
human
perception.
We
simultaneously
recorded
stereoelectroencephalography
data
from
prefrontal
cortex
(PFC),
while
patients
implanted
electrodes
performed
a
visual
consciousness
task.
Compared
ventral
PFC,
intralaminar
medial
presented
earlier
stronger
consciousness-related
activity.
Transient
thalamofrontal
neural
synchrony
cross-frequency
coupling
were
both
driven
by
θ
phase
during
The
thus
play
gate
role
drive
PFC
emergence
In
ambiguous
or
conflicting
sensory
situations,
perception
is
often
'multistable'
in
that
it
perpetually
changes
at
irregular
intervals,
shifting
abruptly
between
distinct
alternatives.
The
interval
statistics
of
these
alternations
exhibits
quasi-universal
characteristics,
suggesting
a
general
mechanism.
Using
binocular
rivalry,
we
show
many
aspects
this
perceptual
dynamics
are
reproduced
by
hierarchical
model
operating
out
equilibrium.
constitutive
elements
idealize
the
metastability
cortical
networks.
Independent
accumulate
visual
evidence
one
level,
while
groups
coupled
compete
for
dominance
another
level.
As
soon
as
group
dominates
perception,
feedback
inhibition
suppresses
supporting
evidence.
Previously
unreported
features
serial
dependencies
compellingly
corroborate
Moreover,
proposed
out-of-equilibrium
satisfies
normative
constraints
continuous
decision-making.
Thus,
multistable
may
reflect
decision-making
volatile
world:
integrating
over
space
and
time,
choosing
categorically
hypotheses,
concurrently
evaluating
Research Square (Research Square),
Год журнала:
2024,
Номер
unknown
Опубликована: Июнь 19, 2024
Abstract
How
does
our
brain
resolve
conflicts
in
sensory
input
to
generate
conscious
perception?
Using
high-resolution
7T
fMRI,
we
addressed
this
question
by
investigating
column-
and
layer-specific
activity
cortical
subcortical
regions
humans
during
binocular
rivalry.
Results
showed
that
eye-specific
rivalry
modulation
arises
from
lateral
inhibition
between
adjacent
ocular
dominance
columns
the
superficial
layers
of
primary
visual
cortex
(V1),
but
not
geniculate
nucleus
(LGN)
thalamus.
Furthermore,
data
support
an
active
role
feedback
signals
intraparietal
sulcus
(IPS)
biasing
synchronizing
local
competitions
V1
into
perceptually
coherent
representations,
even
absence
awareness
eye-of-origin
information.
These
findings
revealed
mesoscale
neural
circuitry
perceptual
conflict
resolution
humans:
is
resolved
inhibitory
microcircuits
early
cortex,
while
parietal
attention
network
bias
integrate
a
unified
perception.
