bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2018,
Volume and Issue:
unknown
Published: Sept. 16, 2018
Hippocampal
neurons
fire
selectively
in
local
behavioral
contexts
such
as
the
position
an
environment
or
phase
of
a
task,
1-3
and
are
thought
to
form
cognitive
map
task-relevant
variables.
1,4,5
However,
their
activity
varies
over
repeated
conditions,
6
different
runs
through
same
trials.
Although
widely
observed
across
brain,
7-10
variability
is
not
well
understood,
could
reflect
noise
structure,
encoding
additional
information.
6,11-13
Here,
we
introduce
conceptual
model
explain
terms
underlying,
population-level
structure
single-trial
neural
activity.
To
test
this
model,
developed
novel
unsupervised
learning
algorithm
incorporating
temporal
dynamics,
order
characterize
population
trajectory
on
nonlinear
manifold—a
space
possible
network
states.
The
manifold’s
captures
correlations
between
relationships
states,
constraints
arising
from
underlying
architecture
inputs.
Using
measurements
time
but
no
information
about
exogenous
variables,
recovered
hippocampal
manifolds
during
spatial
non-spatial
tasks
rats.
Manifolds
were
low-dimensional
smoothly
encoded
task-related
contained
extra
dimension
reflecting
beyond
measured
Consistent
with
our
fired
function
overall
state,
fluctuations
trials
corresponded
variation
manifold.
In
particular,
allowed
system
take
trajectories
despite
conditions.
Furthermore,
temporarily
decouple
current
conditions
traverse
neighboring
manifold
points
corresponding
past,
future,
nearby
Our
results
suggest
that
trial-to-trial
hippocampus
structured,
may
operation
internal
processes.
well-suited
for
organizing
support
memory,
1,5,14
planning,
12,15,16
reinforcement
learning.
17,18
general,
approach
find
broader
use
probing
organization
computational
role
circuit
dynamics
other
brain
regions.
Ascending
neuromodulatory
projections
from
the
locus
coeruleus
(LC)
affect
cortical
neural
networks
via
release
of
norepinephrine
(NE).
However,
exact
nature
these
effects
on
activity
patterns
in
vivo
is
not
well
understood.
Here,
we
show
that
awake
monkeys,
LC
activation
associated
with
changes
coordinated
anterior
cingulate
cortex
(ACC).
These
relationships,
which
are
largely
independent
firing
rates
individual
ACC
neurons,
depend
type
activation:
pairwise
correlations
tend
to
be
reduced
when
ongoing
(baseline)
increases
but
enhanced
external
events
evoke
transient
responses.
Both
relationships
covary
pupil
reflect
and
arousal.
results
suggest
modulations
information
processing
can
result
partly
ongoing,
context-dependent,
arousal-related
LC-NE
system.
Cell Reports,
Journal Year:
2024,
Volume and Issue:
43(6), P. 114274 - 114274
Published: May 25, 2024
A
signal
mixer
facilitates
rich
computation,
which
has
been
the
building
block
of
modern
telecommunication.
This
frequency
mixing
produces
new
signals
at
sum
and
difference
frequencies
input
signals,
enabling
powerful
operations
such
as
heterodyning
multiplexing.
Here,
we
report
that
a
neuron
is
mixer.
We
found
through
ex
vivo
in
whole-cell
measurements
neurons
mix
exogenous
(controlled)
endogenous
(spontaneous)
subthreshold
membrane
potential
oscillations,
producing
oscillation
frequencies,
neural
originates
voltage-gated
ion
channels.
Furthermore,
demonstrate
evident
human
brain
activity
associated
with
cognitive
functions.
electroencephalogram
displays
distinct
clusters
local
inter-region
conversion
salient
posterior
alpha-beta
oscillations
into
gamma-band
regulates
visual
attention.
Signal
may
enable
individual
to
sculpt
spectrum
circuit
utilize
them
for
computational
operations.
PLoS Computational Biology,
Journal Year:
2018,
Volume and Issue:
14(8), P. e1006381 - e1006381
Published: Aug. 27, 2018
Functional-effective
connectivity
and
network
topology
are
nowadays
key
issues
for
studying
brain
physiological
functions
pathologies.
Inferring
neuronal
from
electrophysiological
recordings
presents
open
challenges
unsolved
problems.
In
this
work,
we
present
a
cross-correlation
based
method
reliably
estimating
not
only
excitatory
but
also
inhibitory
links,
by
analyzing
multi-unit
spike
activity
large-scale
networks.
The
is
validated
means
of
realistic
simulations
populations.
New
results
related
to
functional
estimation
identification
obtained
experimental
high-density
(i.e.,
4096
electrodes)
microtransducer
arrays
coupled
in
vitro
neural
populations
presented.
Specifically,
show
that:
(i)
connections
accurately
identified
cortical
networks,
providing
that
reasonable
firing
rate
recording
length
achieved;
(ii)
small-world
topology,
with
scale-free
rich-club
features
obtained,
on
condition
minimum
number
active
sites
available.
procedure
can
be
directly
extended
applied
vivo
multi-units
recordings.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2018,
Volume and Issue:
unknown
Published: Sept. 16, 2018
Hippocampal
neurons
fire
selectively
in
local
behavioral
contexts
such
as
the
position
an
environment
or
phase
of
a
task,
1-3
and
are
thought
to
form
cognitive
map
task-relevant
variables.
1,4,5
However,
their
activity
varies
over
repeated
conditions,
6
different
runs
through
same
trials.
Although
widely
observed
across
brain,
7-10
variability
is
not
well
understood,
could
reflect
noise
structure,
encoding
additional
information.
6,11-13
Here,
we
introduce
conceptual
model
explain
terms
underlying,
population-level
structure
single-trial
neural
activity.
To
test
this
model,
developed
novel
unsupervised
learning
algorithm
incorporating
temporal
dynamics,
order
characterize
population
trajectory
on
nonlinear
manifold—a
space
possible
network
states.
The
manifold’s
captures
correlations
between
relationships
states,
constraints
arising
from
underlying
architecture
inputs.
Using
measurements
time
but
no
information
about
exogenous
variables,
recovered
hippocampal
manifolds
during
spatial
non-spatial
tasks
rats.
Manifolds
were
low-dimensional
smoothly
encoded
task-related
contained
extra
dimension
reflecting
beyond
measured
Consistent
with
our
fired
function
overall
state,
fluctuations
trials
corresponded
variation
manifold.
In
particular,
allowed
system
take
trajectories
despite
conditions.
Furthermore,
temporarily
decouple
current
conditions
traverse
neighboring
manifold
points
corresponding
past,
future,
nearby
Our
results
suggest
that
trial-to-trial
hippocampus
structured,
may
operation
internal
processes.
well-suited
for
organizing
support
memory,
1,5,14
planning,
12,15,16
reinforcement
learning.
17,18
general,
approach
find
broader
use
probing
organization
computational
role
circuit
dynamics
other
brain
regions.