NeuroImage,
Journal Year:
2017,
Volume and Issue:
155, P. 406 - 421
Published: March 2, 2017
The
development
of
large-scale
network
models
that
infer
the
effective
(directed)
connectivity
among
neuronal
populations
from
neuroimaging
data
represents
a
key
challenge
for
computational
neuroscience.
Dynamic
causal
(DCMs)
and
electrophysiological
are
frequently
used
inferring
but
presently
restricted
to
small
graphs
(typically
up
10
regions)
in
order
keep
model
inversion
computationally
feasible.
Here,
we
present
novel
variant
DCM
functional
magnetic
resonance
imaging
(fMRI)
is
suited
assess
large
(whole-brain)
networks.
approach
rests
on
translating
linear
into
frequency
domain
reformulating
it
as
special
case
Bayesian
regression.
This
paper
derives
regression
(rDCM)
detail
presents
variational
method
enables
extremely
fast
inference
accelerates
by
several
orders
magnitude
compared
classical
DCM.
Using
both
simulated
empirical
data,
demonstrate
face
validity
rDCM
under
different
settings
signal-to-noise
ratio
(SNR)
repetition
time
(TR)
fMRI
data.
In
particular,
potential
utility
tool
whole-brain
connectomics
challenging
connection
strengths
comprising
66
regions
300
free
parameters.
Our
results
indicate
highly
efficient
with
promising
individual
Biological Psychiatry,
Journal Year:
2018,
Volume and Issue:
84(9), P. 634 - 643
Published: May 25, 2018
Fueled
by
developments
in
computational
neuroscience,
there
has
been
increasing
interest
the
underlying
neurocomputational
mechanisms
of
psychosis.
One
successful
approach
involves
predictive
coding
and
Bayesian
inference.
Here,
inferences
regarding
current
state
world
are
made
combining
prior
beliefs
with
incoming
sensory
signals.
Mismatches
between
signals
constitute
prediction
errors
that
drive
new
learning.
Psychosis
suggested
to
result
from
a
decreased
precision
encoding
relative
data,
thereby
garnering
maladaptive
inferences.
we
review
evidence
for
aberrant
discuss
challenges
this
canonical
account
For
example,
hallucinations
delusions
may
relate
distinct
alterations
coding,
despite
their
common
co-occurrence.
More
broadly,
some
studies
implicate
weakened
psychosis,
others
find
stronger
priors.
These
might
be
answered
more
nuanced
view
coding.
Different
priors
specified
different
modalities
integration,
deficits
each
modality
need
not
uniform.
Furthermore,
hierarchical
organization
critical.
Altered
processes
at
lower
levels
hierarchy
linearly
related
higher
(and
vice
versa).
Finally,
theories
do
highlight
active
inference—the
process
through
which
effects
our
actions
on
sensations
anticipated
minimized.
It
is
possible
conflicting
findings
reconciled
considering
these
complexities,
portending
framework
psychosis
equipped
deal
its
many
manifestations.
NeuroImage,
Journal Year:
2016,
Volume and Issue:
145, P. 377 - 388
Published: July 29, 2016
Individual
variability
has
clear
effects
upon
the
outcome
of
therapies
and
treatment
approaches.
The
customization
healthcare
options
to
individual
patient
should
accordingly
improve
results.
We
propose
a
novel
approach
brain
interventions
based
on
personalized
network
models
derived
from
non-invasive
structural
data
patients.
Along
example
with
bitemporal
epilepsy,
we
show
step
by
how
develop
Virtual
Epileptic
Patient
(VEP)
model
integrate
patient-specific
information
such
as
connectivity,
epileptogenic
zone
MRI
lesions.
Using
high-performance
computing,
systematically
carry
out
parameter
space
explorations,
fit
validate
against
patient's
empirical
stereotactic
EEG
(SEEG)
demonstrate
strategies
towards
therapy
intervention.
Frontiers in Human Neuroscience,
Journal Year:
2016,
Volume and Issue:
10
Published: Nov. 15, 2016
This
paper
outlines
a
hierarchical
Bayesian
framework
for
interoception,
homeostatic/allostatic
control,
and
meta-cognition
that
connects
fatigue
depression
to
the
experience
of
chronic
dyshomeostasis.
Specifically,
viewing
interoception
as
inversion
generative
model
viscerosensory
inputs
allows
formal
definition
dyshomeostasis
(as
chronically
enhanced
surprise
about
bodily
signals,
or,
equivalently,
low
evidence
brain’s
states)
allostasis
change
in
prior
beliefs
or
predictions
which
define
setpoints
homeostatic
reflex
arcs).
Critically,
we
propose
performance
interoceptive-allostatic
circuitry
is
monitored
by
metacognitive
layer
updates
capacity
successfully
regulate
states
(allostatic
self-efficacy).
In
this
framework,
can
be
understood
sequential
responses
interoceptive
ensuing
diagnosis
allostatic
self-efficacy.
While
might
represent
an
early
response
with
adaptive
value
(cf.
sickness
behaviour),
may
trigger
generalised
belief
self-efficacy
lack
control
learned
helplessness),
resulting
depression.
perspective
implies
alternative
pathophysiological
mechanisms
are
reflected
differential
abnormalities
effective
connectivity
circuits
allostasis.
We
discuss
suitably
extended
models
could
distinguish
these
patterns
individual
patients
help
inform
future.
Science,
Journal Year:
2014,
Volume and Issue:
346(6209), P. 572 - 578
Published: Oct. 30, 2014
Human
cognitive
aging
differs
between
and
is
malleable
within
individuals.
In
the
absence
of
a
strong
genetic
program,
it
open
to
host
hazards,
such
as
vascular
conditions,
metabolic
syndrome,
chronic
stress,
but
also
protective
enhancing
factors,
experience-dependent
plasticity.
Longitudinal
studies
suggest
that
leading
an
intellectually
challenging,
physically
active,
socially
engaged
life
may
mitigate
losses
consolidate
gains.
Interventions
help
identify
contexts
mechanisms
successful
give
science
society
hint
about
what
would
be
possible
if
conditions
were
different.
Journal of Neurology Neurosurgery & Psychiatry,
Journal Year:
2015,
Volume and Issue:
unknown, P. jnnp - 310737
Published: July 8, 2015
Computational
Psychiatry
aims
to
describe
the
relationship
between
brain9s
neurobiology,
its
environment
and
mental
symptoms
in
computational
terms.
In
so
doing,
it
may
improve
psychiatric
classification
diagnosis
treatment
of
illness.
It
can
unite
many
levels
description
a
mechanistic
rigorous
fashion,
while
avoiding
biological
reductionism
artificial
categorisation.
We
how
models
cognition
infer
current
state
weigh
up
future
actions,
these
provide
new
perspectives
on
two
example
disorders,
depression
schizophrenia.
Reinforcement
learning
describes
brain
choose
value
courses
actions
according
their
long-term
value.
Some
depressive
result
from
aberrant
valuations,
which
could
arise
prior
beliefs
about
loss
agency
(‘helplessness’),
or
an
inability
inhibit
exploration
aversive
events.
Predictive
coding
explains
might
perform
Bayesian
inference
by
combining
sensory
data
with
beliefs,
each
weighted
certainty
(or
precision).
Several
cortical
abnormalities
schizophrenia
reduce
precision
at
higher
inferential
hierarchy,
biasing
towards
away
beliefs.
discuss
whether
striatal
hyperdopaminergia
have
adaptive
function
this
context,
also
reinforcement
incentive
salience
shed
light
disorder.
Finally,
we
review
some
Psychiatry9s
applications
neurological
such
as
Parkinson9s
disease,
pitfalls
avoid
when
applying
methods.