Methods in microscopy,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 14, 2024
Abstract
The
three-dimensional
visualization
of
cellular
architecture
by
volume
electron
microscopy
(vEM)
has
reignited
interest
in
morphological
descriptions
complex
tissue.
At
the
same
time,
increasing
availability
vEM
life
sciences
was
foundation
for
accelerated
development
analysis
pipelines
with
automated
software
tools
segmentation
and
3D
reconstruction.
This
progress
results
continuous
generation
large
amounts
data
that
hold
a
treasure
box
new
scientific
insights
waiting
discovery.
Automated
provides
quantitative
readouts
organellar
properties,
while
open
datasets
creates
opportunity
to
address
diversity
research
questions.
Here,
we
discuss
sample
preparation
strategies
showcase
how
this
methodology
contributed
our
knowledge
myelin
biology
disease.
Furthermore,
intent
inform
users
about
developments
field
instrumentation,
methods
potential
contribute
other
areas
research.
Neuron,
Год журнала:
2024,
Номер
112(6), С. 991 - 1000.e8
Опубликована: Янв. 21, 2024
In
the
neocortex,
neural
activity
is
shaped
by
interaction
of
excitatory
and
inhibitory
neurons,
defined
organization
their
synaptic
connections.
Although
connections
among
pyramidal
neurons
are
sparse
functionally
tuned,
connectivity
thought
to
be
dense
largely
unstructured.
By
measuring
in
vivo
visual
responses
parvalbumin-expressing
(PV+)
cells
mouse
primary
cortex,
we
show
that
weights
nearby
specifically
tuned
according
similarity
cells'
responses.
Individual
PV+
strongly
inhibit
those
provide
them
with
strong
excitation
share
selectivity.
This
structured
provides
a
circuit
mechanism
for
inhibition
onto
despite
connectivity,
stabilizing
within
feature-specific
ensembles
while
supporting
competition
between
them.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2021,
Номер
unknown
Опубликована: Июль 29, 2021
Abstract
To
understand
the
brain
we
must
relate
neurons’
functional
responses
to
circuit
architecture
that
shapes
them.
Here,
present
a
large
connectomics
dataset
with
dense
calcium
imaging
of
millimeter
scale
volume.
We
recorded
activity
from
approximately
75,000
neurons
in
primary
visual
cortex
(VISp)
and
three
higher
areas
(VISrl,
VISal
VISlm)
an
awake
mouse
viewing
natural
movies
synthetic
stimuli.
The
data
were
co-registered
volumetric
electron
microscopy
(EM)
reconstruction
containing
more
than
200,000
cells
0.5
billion
synapses.
Subsequent
proofreading
subset
this
volume
yielded
reconstructions
include
complete
dendritic
trees
as
well
local
inter-areal
axonal
projections
map
up
thousands
cell-to-cell
connections
per
neuron.
release
open-access
resource
scientific
community
including
set
tools
facilitate
retrieval
downstream
analysis.
In
accompanying
papers
describe
our
findings
using
provide
comprehensive
structural
characterization
cortical
cell
types
1–3
most
detailed
synaptic
level
connectivity
diagram
column
date
2
,
uncovering
unique
cell-type
specific
inhibitory
motifs
can
be
linked
gene
expression
4
.
Functionally,
identify
new
computational
principles
how
information
is
integrated
across
space
5
characterize
novel
neuronal
invariances
6
bring
structure
function
together
decipher
general
principle
wires
excitatory
within
7,
8
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2023,
Номер
unknown
Опубликована: Май 13, 2023
Abstract
Deciphering
the
brain’s
structure-function
relationship
is
key
to
understanding
neuronal
mechanisms
underlying
perception
and
cognition.
The
cortical
column,
a
vertical
organization
of
neurons
with
similar
functions,
classic
example
primate
neocortex
organization.
While
columns
have
been
identified
in
primary
sensory
areas
using
parametric
stimuli,
their
prevalence
across
higher-level
cortex
debated.
A
hurdle
identifying
difficulty
characterizing
complex
nonlinear
tuning,
especially
high-dimensional
inputs.
Here,
we
asked
whether
area
V4,
mid-level
macaque
visual
system,
organized
into
columns.
We
combined
large-scale
linear
probe
recordings
deep
learning
methods
systematically
characterize
tuning
>1,200
V4
silico
synthesis
most
exciting
images
(MEIs),
followed
by
vivo
verification.
found
that
MEIs
single
exhibited
features
like
textures,
shapes,
or
even
high-level
attributes
such
as
eye-like
structures.
Neurons
recorded
on
same
silicon
probe,
inserted
orthogonal
surface,
were
selective
spatial
features,
expected
from
columnar
quantified
this
finding
human
psychophysics
measuring
MEI
similarity
non-linear
embedding
space,
learned
contrastive
loss.
Moreover,
selectivity
population
was
clustered,
suggesting
form
distinct
functional
groups
shared
feature
selectivity,
reminiscent
cell
types.
These
closely
mirrored
maps
units
artificial
vision
systems,
hinting
at
encoding
principles
between
biological
vision.
Our
findings
provide
evidence
types
may
constitute
universal
organizing
neocortex,
simplifying
cortex’s
complexity
simpler
circuit
motifs
which
perform
canonical
computations.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2023,
Номер
unknown
Опубликована: Март 24, 2023
The
complexity
of
neural
circuits
makes
it
challenging
to
decipher
the
brain’s
algorithms
intelligence.
Recent
break-throughs
in
deep
learning
have
produced
models
that
accurately
simulate
brain
activity,
enhancing
our
understanding
computational
objectives
and
coding.
However,
these
struggle
generalize
beyond
their
training
distribution,
limiting
utility.
emergence
foundation
models,
trained
on
vast
datasets,
has
introduced
a
new
AI
paradigm
with
remarkable
generalization
capabilities.
We
collected
large
amounts
activity
from
visual
cortices
multiple
mice
model
predict
neuronal
responses
arbitrary
natural
videos.
This
generalized
minimal
successfully
predicted
across
various
stimulus
domains,
such
as
coherent
motion
noise
patterns.
It
could
also
be
adapted
tasks
prediction,
predicting
anatomical
cell
types,
dendritic
features,
connectivity
within
MICrONS
functional
connectomics
dataset.
Our
work
is
crucial
step
toward
building
models.
As
neuroscience
accumulates
larger,
multi-modal
will
uncover
statistical
regularities,
enabling
rapid
adaptation
accelerating
research.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2023,
Номер
unknown
Опубликована: Март 15, 2023
We
are
now
in
the
era
of
millimeter-scale
electron
microscopy
(EM)
volumes
collected
at
nanometer
resolution
(Shapson-Coe
et
al.,
2021;
Consortium
2021).
Dense
reconstruction
cellular
compartments
these
EM
has
been
enabled
by
recent
advances
Machine
Learning
(ML)
(Lee
2017;
Wu
Lu
Macrina
Automated
segmentation
methods
produce
exceptionally
accurate
reconstructions
cells,
but
post-hoc
proofreading
is
still
required
to
generate
large
connectomes
free
merge
and
split
errors.
The
elaborate
3-D
meshes
neurons
contain
detailed
morphological
information
multiple
scales,
from
diameter,
shape,
branching
patterns
axons
dendrites,
down
fine-scale
structure
dendritic
spines.
However,
extracting
features
can
require
substantial
effort
piece
together
existing
tools
into
custom
workflows.
Building
on
open-source
software
for
mesh
manipulation,
here
we
present
“NEURD”,
a
package
that
decomposes
meshed
compact
extensively-annotated
graph
representations.
With
feature-rich
graphs,
automate
variety
tasks
such
as
state
art
automated
errors,
cell
classification,
spine
detection,
axon-dendritic
proximities,
other
annotations.
These
enable
many
downstream
analyses
neural
morphology
connectivity,
making
massive
complex
datasets
more
accessible
neuroscience
researchers
focused
scientific
questions.
Multi-electrode
arrays
covering
several
square
millimeters
of
neural
tissue
provide
simultaneous
access
to
population
signals
such
as
extracellular
potentials
and
spiking
activity
one
hundred
or
more
individual
neurons.
The
interpretation
the
recorded
data
calls
for
multiscale
computational
models
with
corresponding
spatial
dimensions
signal
predictions.
Multi-layer
neuron
network
local
cortical
circuits
about
$1\,{\text{mm}^{2}}$
have
been
developed,
integrating
experimentally
obtained
neuron-type-specific
connectivity
reproducing
features
observed
in-vivo
statistics.
Local
field
can
be
computed
from
simulated
activity.
We
here
extend
a
potential
model
an
area
$4\times
4\,{\text{mm}^{2}}$,
preserving
density
introducing
distance-dependent
connection
probabilities
conduction
delays.
find
that
upscaling
procedure
preserves
overall
statistics
original
reproduces
asynchronous
irregular
across
populations
weak
pairwise
spike-train
correlations
in
agreement
experimental
recordings
sensory
cortex.
Also
compatible
observations,
correlation
is
strong
decays
over
distance
micrometers.
Enhanced
coherence
low-gamma
band
around
$50\,\text{Hz}$
may
explain
recent
report
apparent
band-pass
filter
effect
reach
potential.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 16, 2025
Organisms
continually
tune
their
perceptual
systems
to
the
features
they
encounter
in
environment
1-3
.
We
have
studied
how
ongoing
experience
reorganizes
synaptic
connectivity
of
neurons
olfactory
(piriform)
cortex
mouse.
developed
an
approach
measure
vivo
,
training
a
deep
convolutional
network
reliably
identify
monosynaptic
connections
from
spike-time
cross-correlograms
4.4
million
single-unit
pairs.
This
revealed
that
excitatory
piriform
with
similar
odor
tuning
are
more
likely
be
connected.
asked
whether
enhances
this
like-to-like
but
found
it
was
unaffected
by
exposure.
Experience
did,
however,
alter
logic
interneuron
connectivity.
Following
repeated
encounters
set
odorants,
inhibitory
responded
differentially
these
stimuli
exhibited
high
degree
both
incoming
and
outgoing
within
cortical
network.
reorganization
depended
only
on
not
its
pre-
or
postsynaptic
partners.
A
computational
model
reorganized
predicts
increases
dimensionality
entire
network's
responses
familiar
stimuli,
thereby
enhancing
discriminability.
confirmed
network-level
property
is
present
physiological
measurements,
which
showed
increased
separability
evoked
versus
novel
odorants.
Thus,
simple,
non-Hebbian
may
selectively
enhance
organism's
discrimination
environment.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2025,
Номер
unknown
Опубликована: Март 15, 2025
Accumulating
information
is
a
critical
component
of
most
circuit
computations
in
the
brain
across
species,
yet
its
precise
implementation
at
synaptic
level
remains
poorly
understood.
Dissecting
such
neural
circuits
vertebrates
requires
knowledge
functional
properties
and
ability
to
directly
correlate
dynamics
with
underlying
wiring
diagram
same
animal.
Here
we
combine
calcium
imaging
ultrastructural
reconstruction,
using
visual
motion
accumulation
paradigm
larval
zebrafish.
Using
connectomic
analyses
functionally
identified
cells
computational
modeling,
show
that
bilateral
inhibition,
disinhibition,
recurrent
connectivity
are
prominent
motifs
for
sensory
within
anterior
hindbrain.
We
also
demonstrate
similar
insights
about
structure-function
relationship
this
can
be
obtained
through
complementary
methods
involving
cell-specific
morphological
labeling
via
photo-conversion
neuronal
response
types.
used
our
unique
ground
truth
datasets
train
test
novel
classifier
algorithm,
allowing
us
assign
labels
neurons
from
libraries
where
lacking.
The
resulting
feature-rich
library
identities
connectomes
enabled
constrain
biophysically
realistic
network
model
hindbrain
reproduce
observed
make
testable
predictions
future
experiments.
Our
work
exemplifies
power
hypothesis-driven
electron
microscopy
paired
recordings
gain
mechanistic
into
signal
processing
provides
framework
dissecting
vertebrates.