Frontiers in Molecular Neuroscience,
Journal Year:
2024,
Volume and Issue:
17
Published: May 15, 2024
Dm9
neurons
in
Drosophila
have
been
proposed
as
functional
homologs
of
horizontal
cells
the
outer
retina
vertebrates.
Here
we
combine
genetic
dissection
neuronal
circuit
function,
two-photon
calcium
imaging
and
inner
photoreceptors,
immunohistochemical
analysis
to
reveal
novel
insights
into
role
early
visual
processing.
Our
experiments
show
that
receive
input
from
all
four
types
photoreceptor
R7p,
R7y,
R8p,
R8y.
Histamine
released
R7/R8
directly
inhibits
via
histamine
receptor
Ort,
outweighs
simultaneous
histamine-independent
excitation
by
UV-sensitive
R7.
turn
provides
inhibitory
feedback
R7/R8,
which
is
sufficient
for
color-opponent
processing
R7
but
not
R8.
Color
opponent
R8
requires
additional
synaptic
inhibition
same
ommatidium
axo-axonal
synapses
second
HisCl1.
Notably,
optogenetic
prohibits
color
decreases
intracellular
terminals.
The
latter
likely
results
reduced
release
excitatory
glutamate
shifts
overall
sensitivity
toward
higher
light
intensities.
In
summary,
our
underscore
a
key
suggest
regulating
adaptation
photoreceptors.
These
findings
on
are
indeed
reminiscent
versatile
functions
vertebrate
retina.
Genetics,
Journal Year:
2023,
Volume and Issue:
224(2)
Published: May 2, 2023
Abstract
Originally
a
genetic
model
organism,
the
experimental
use
of
Drosophila
melanogaster
has
grown
to
include
quantitative
behavioral
analyses,
sophisticated
perturbations
neuronal
function,
and
detailed
sensory
physiology.
A
highlight
these
developments
can
be
seen
in
context
vision,
where
pioneering
studies
have
uncovered
fundamental
generalizable
principles
processing.
Here
we
begin
with
an
overview
vision-guided
behaviors
common
methods
for
probing
visual
circuits.
We
then
outline
anatomy
physiology
brain
regions
involved
processing,
beginning
at
periphery
ending
descending
motor
control.
Areas
focus
contrast
motion
detection
optic
lobe,
circuits
feature
selectivity,
computations
support
spatial
navigation,
contextual
associative
learning.
Finally,
look
future
fly
neuroscience
discuss
promising
topics
further
study.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Oct. 13, 2023
A
catalog
of
neuronal
cell
types
has
often
been
called
a
"parts
list"
the
brain,
and
regarded
as
prerequisite
for
understanding
brain
function.
In
optic
lobe
Nature Communications,
Journal Year:
2023,
Volume and Issue:
14(1)
Published: Nov. 24, 2023
Color
and
motion
are
used
by
many
species
to
identify
salient
objects.
They
processed
largely
independently,
but
color
contributes
processing
in
humans,
for
example,
enabling
moving
colored
objects
be
detected
when
their
luminance
matches
the
background.
Here,
we
demonstrate
an
unexpected,
additional
contribution
of
vision
Drosophila.
We
show
that
behavioral
ON-motion
responses
more
sensitive
UV
than
OFF-motion,
cellular
pathways
connecting
UV-sensitive
R7
photoreceptors
ON
OFF-motion-sensitive
T4
T5
cells,
using
neurogenetics
calcium
imaging.
Remarkably,
this
circuitry
enhances
detection
approaching
discs,
not
green
discs
with
same
chromatic
contrast,
how
could
generalize
systems
ON-
OFF-motion
pathways.
Our
results
provide
a
computational
circuit
basis
favor
saliently
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: Feb. 21, 2024
Visual
systems
are
homogeneous
structures,
where
repeating
columnar
units
retinotopically
cover
the
visual
field.
Each
of
these
columns
contain
many
same
neuron
types
that
distinguished
by
anatomic,
genetic
and
-
generally
functional
properties.
However,
there
exceptions
to
this
rule.
In
800
Drosophila
eye,
is
an
anatomically
genetically
identifiable
cell
type
with
variable
properties,
Tm9.
Since
anatomical
connectivity
shapes
neuronal
we
identified
presynaptic
inputs
several
hundred
Tm9s
across
both
optic
lobes
using
full
adult
female
fly
brain
(FAFB)
electron
microscopic
dataset
FlyWire
connectome.
Our
work
shows
Tm9
has
three
major
sparsely
distributed
inputs.
This
differs
from
other
Tm
neurons,
which
have
only
one
major,
more
stereotypic
than
Genetic
synapse
labeling
showed
heterogeneous
wiring
exists
individuals.
Together,
our
data
argue
system
uses
heterogeneous,
circuit
properties
achieve
robust
processing.
The
accurate
processing
of
contrast
is
the
basis
for
all
visually
guided
behaviors.
Visual
scenes
with
rapidly
changing
illumination
challenge
computation
because
photoreceptor
adaptation
not
fast
enough
to
compensate
such
changes.
Yet,
human
perception
stable
even
when
visual
environment
quickly
changing,
suggesting
rapid
post
receptor
luminance
gain
control.
Similarly,
in
fruit
fly
Drosophila,
control
leads
invariant
behavior
moving
OFF
stimuli.
Here,
we
show
that
behavioral
responses
ON
stimuli
also
utilize
a
gain,
and
ON-motion
depends
on
inputs
from
three
first-order
interneurons
L1,
L2,
L3.
Each
these
neurons
encodes
differently
distributes
information
asymmetrically
across
both
contrast-selective
pathways.
Behavioral
rely
luminance-based
correction
provided
by
L1
L3,
wherein
supports
linearly,
L3
non-linearly
amplifies
dim
Therefore,
are
specific
pathways
but
lamina
serves
as
separate
layer
distinct
support
varying
conditions.
Current Biology,
Journal Year:
2023,
Volume and Issue:
33(13), P. 2632 - 2645.e6
Published: June 6, 2023
Animals
navigating
in
natural
environments
must
handle
vast
changes
their
sensory
input.
Visual
systems,
for
example,
luminance
at
many
timescales,
from
slow
across
the
day
to
rapid
during
active
behavior.
To
maintain
luminance-invariant
perception,
visual
systems
adapt
sensitivity
changing
different
timescales.
We
demonstrate
that
gain
control
photoreceptors
alone
is
insufficient
explain
invariance
both
fast
and
timescales
reveal
algorithms
adjust
past
fly
eye.
combined
imaging
behavioral
experiments
with
computational
modeling
show
downstream
of
photoreceptors,
circuitry
taking
input
single
luminance-sensitive
neuron
type
L3
implements
This
computation
bidirectional
it
prevents
underestimation
contrasts
low
overestimation
high
luminance.
An
algorithmic
model
disentangles
these
multifaceted
contributions
shows
occurs
The
a
nonlinear
interaction
contrast
achieve
correction
dark-sensitive
channel
improve
detection
dim
stimuli
Together,
our
work
demonstrates
how
neuronal
performs
diverse
computations
implement
multiple
are
together
important
navigation
environments.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: April 8, 2024
Abstract
Normalization
is
a
fundamental
operation
in
image
processing.
Convolutional
nets
have
evolved
to
include
large
number
of
normalizations
(Ioffe
and
Szegedy
2015;
Ulyanov,
Vedaldi,
Lempitsky
2016;
Wu
He
2018),
this
architectural
shift
has
proved
essential
for
robust
computer
vision
(He
et
al.
Bjorck
2018;
Santurkar,
Tsipras,
Ilyas
2018).
Studies
biological
vision,
contrast,
invoked
just
one
or
few
model
psychophysical
(Mach
1868;
Furman
1965;
Sperling
1970)
physiological
(Carandini
Heeger
2011;
Shin
Adesnik
2024)
observations
that
accumulated
over
century.
Here
connectomic
information
(Matsliah
2023)
used
argue
interneurons
the
fly
visual
system
support
with
unprecedented
specificity.
Ten
interneuron
types
distal
medulla
(Dm)
optic
lobe,
example,
appear
chiefly
spatial
normalizations,
each
which
specific
single
cell
type
length
scale.
Another
Dm
supports
normalization
features
as
well
space.
Two
outlier
do
not
at
all.
Interneuron
likely
be
normalizers
are
identified
only
but
also
all
other
families
lobe.
For
diversity
appears
an
inevitable
consequence
specificity
normalizations.