The Journal of Physiology,
Год журнала:
2022,
Номер
601(15), С. 3071 - 3090
Опубликована: Сен. 7, 2022
Abstract
In
the
brain,
patterns
of
neural
activity
represent
sensory
information
and
store
it
in
non‐random
synaptic
connectivity.
A
prominent
theoretical
hypothesis
states
that
assemblies,
groups
neurons
are
strongly
connected
to
each
other,
key
computational
units
underlying
perception
memory
formation.
Compatible
with
these
hypothesised
experiments
have
revealed
display
synchronous
activity,
either
spontaneously
or
upon
stimulus
presentation,
exhibit
behavioural
relevance.
While
remains
unclear
how
assemblies
form
work
has
vastly
contributed
understanding
various
interacting
mechanisms
this
process.
Here,
we
review
recent
literature
on
assembly
formation
by
categorising
involved
into
four
components:
plasticity,
symmetry
breaking,
competition
stability.
We
highlight
different
approaches
assumptions
behind
discuss
ideas
as
unit
brain.
image
Nature Neuroscience,
Год журнала:
2024,
Номер
27(3), С. 561 - 572
Опубликована: Янв. 19, 2024
Episodic
memories
are
encoded
by
experience-activated
neuronal
ensembles
that
remain
necessary
and
sufficient
for
recall.
However,
the
temporal
evolution
of
memory
engrams
after
initial
encoding
is
unclear.
In
this
study,
we
employed
computational
experimental
approaches
to
examine
how
neural
composition
selectivity
change
with
consolidation.
Our
spiking
network
model
yielded
testable
predictions:
transition
from
unselective
selective
as
neurons
drop
out
into
engrams;
inhibitory
activity
during
recall
essential
selectivity;
synaptic
plasticity
consolidation
critical
become
selective.
Using
activity-dependent
labeling,
longitudinal
calcium
imaging
a
combination
optogenetic
chemogenetic
manipulations
in
mouse
dentate
gyrus,
conducted
contextual
fear
conditioning
experiments
supported
our
model's
predictions.
results
reveal
dynamic
changes
engram
mediated
crucial
emergence
selectivity.
Nature Communications,
Год журнала:
2022,
Номер
13(1)
Опубликована: Май 3, 2022
The
hippocampus
is
thought
to
mediate
episodic
memory
through
the
instantiation
and
reinstatement
of
context-specific
cognitive
maps.
However,
recent
longitudinal
experiments
have
challenged
this
view,
reporting
that
most
hippocampal
cells
change
their
tuning
properties
over
days
even
in
same
environment.
Often
referred
as
neural
or
representational
drift,
these
dynamics
raise
questions
about
capacity
content
code.
One
such
question
whether
how
long-term
impact
code
for
context.
To
address
this,
we
image
large
CA1
populations
more
than
a
month
daily
experience
freely
behaving
mice
participate
an
extended
geometric
morph
paradigm.
We
find
long-timescale
changes
population
activity
occur
orthogonally
representation
context
network
space,
allowing
consistent
readout
contextual
information
across
weeks.
This
population-level
structure
supported
by
heterogeneous
patterns
at
level
individual
cells,
where
observe
evidence
positive
relationship
between
interpretable
coding
stability.
Together,
results
demonstrate
spatial
preserve
relative
representation.
Nature Communications,
Год журнала:
2023,
Номер
14(1)
Опубликована: Авг. 17, 2023
The
basal
ganglia
are
known
to
control
actions
and
modulate
movements.
Neuronal
activity
in
the
two
efferent
pathways
of
dorsal
striatum
is
critical
for
appropriate
behavioral
control.
Previous
evidence
has
led
divergent
conclusions
on
respective
engagement
both
during
actions.
Using
calcium
imaging
evaluate
how
neurons
direct
indirect
encode
behaviors
self-paced
spontaneous
explorations
an
open
field,
we
observed
that
striatal
exhibit
distinct
tuning
properties.
Supervised
learning
algorithms
revealed
pathway
through
their
activation,
whereas
behavior-specific
silencing.
These
properties
remain
stable
weeks.
Our
findings
highlight
a
complementary
encoding
with
congruent
activations
multiple
accessible
given
context,
suppression
competing
behaviors.
This
model
reconciles
previous
conflicting
motor
striatum.
Abstract
Memories
are
encoded
in
neural
ensembles
during
learning
1–6
and
stabilized
by
post-learning
reactivation
7–17
.
Integrating
recent
experiences
into
existing
memories
ensures
that
contain
the
most
recently
available
information,
but
how
brain
accomplishes
this
critical
process
remains
unclear.
Here
we
show
mice,
a
strong
aversive
experience
drives
offline
ensemble
of
not
only
memory
also
neutral
formed
2
days
before,
linking
fear
to
previous
memory.
Fear
specifically
links
retrospectively,
prospectively,
across
days.
Consistent
with
studies,
find
is
reactivated
period
after
learning.
However,
increases
co-reactivation
period.
Ensemble
occurs
more
wake
than
sleep.
Finally,
expression
context
associated
shared
between
memories.
Collectively,
these
results
demonstrate
mechanism
which
integrated
