Cerebral hyperactivation across the Alzheimer’s disease pathological cascade
Brain Communications,
Journal Year:
2024,
Volume and Issue:
6(6)
Published: Jan. 1, 2024
Neuronal
dysfunction
in
specific
brain
regions
or
across
distributed
networks
is
a
known
feature
of
Alzheimer's
disease.
An
often
reported
finding
the
early
stage
disease
presence
increased
functional
MRI
(fMRI)
blood
oxygenation
level-dependent
signal
under
task
conditions
relative
to
cognitively
normal
controls,
phenomenon
as
'hyperactivation'.
However,
research
past
decades
yielded
complex,
sometimes
conflicting
results.
The
magnitude
and
topology
fMRI
hyperactivation
patterns
have
been
found
vary
preclinical
clinical
spectrum
disease,
including
concomitant
'hypoactivation'
some
cases.
These
incongruences
are
likely
due
range
factors,
at
which
cohort
examined,
areas
studied
paradigm
utilized
evoke
these
abnormalities.
Additionally,
perennial
question
pertains
nature
context
Some
propose
it
reflects
compensatory
mechanisms
sustain
cognitive
performance,
while
others
suggest
linked
pathological
disruption
highly
regulated
homeostatic
cycle
that
contributes
to,
even
drives,
progression.
Providing
coherent
narrative
for
empirical
conceptual
discrepancies
paramount
develop
models,
understand
synergy
between
cascade
tailor
effective
interventions.
We
first
provide
comprehensive
overview
changes
spanning
course
from
ageing
then
highlight
evidence
supporting
close
relationship
Language: Английский
Differential effects of aging, Alzheimer’s pathology, andAPOE4on longitudinal functional connectivity and episodic memory in older adults
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 17, 2024
Abstract
INTRODUCTION
Both
aging
and
Alzheimer’s
disease
(AD)
affect
episodic
memory
networks.
How
this
relates
to
region-specific
early
differences
in
functional
connectivity
(FC),
however,
remains
unclear.
METHODS
We
assessed
resting-state
FC
strength
the
medial
temporal
lobe
(MTL)
-
posteromedial
cortex
(PMC)
prefrontal
network
cognition
over
two
years
cognitively
normal
older
adults
from
PREVENT-AD
cohort.
RESULTS
within
PMC
between
posterior
hippocampus
inferomedial
precuneus
decreased
“normal”
(amyloid-
tau-negative
adults).
Lower
was
associated
with
poorer
longitudinal
performance.
Increasing
anterior
superior
related
higher
baseline
AD
pathology.
Higher
differentially
trajectories
depending
on
APOE4
genotype.
DISCUSSION
Findings
suggest
differential
effects
of
pathology
FC.
MTL-PMC
hypoconnectivity
cognitive
decline.
Furthermore,
hyperconnectivity
decline
carriers.
Graphical
abstract.
A)
“Normal
aging”
is
characterized
by
a
decrease
connectivity.
B)
Cognitively
unimpaired
more
at
(measured
via
cerebrospinal
fluid)
exhibit
increase
Language: Английский