The Journal of Physiology,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 20, 2024
Abstract
Previous
studies
established
strong
links
between
morphological
characteristics
of
mammalian
hindlimb
muscles
and
their
sensorimotor
functions
during
locomotion.
Less
is
known
about
the
role
forelimb
morphology
in
motor
outputs
generation
sensory
signals.
Here,
we
measured
46
from
six
cats.
These
included
muscle
attachments,
physiological
cross‐sectional
area
(PCSA)
fascicle
length.
We
also
recorded
full‐body
mechanics
EMG
activity
level
overground
treadmill
locomotion
seven
16
adult
cats
either
sex,
respectively.
computed
forces
along
with
force‐
length‐dependent
signals
mapped
onto
corresponding
cervical
spinal
segments.
found
that
patterns
afferent
activities
were
strongly
affected
by
muscle's
moment
arm,
PCSA
Morphology
shoulder
suggests
distinct
roles
forelimbs
lateral
force
production
movements.
Patterns
long
fibres
(brachioradialis,
extensor
carpi
radialis)
closely
matched
overall
length,
whereas
pattern
biceps
brachii
length
afferents
orientation.
conclude
cat
contributes
substantially
to
locomotor
function,
particularly
control
stability
turning,
rather
than
propulsion.
image
Key
points
Little
producing
generating
somatosensory
This
information
needed
understand
contributions
control.
forelimbs,
walking
electromyographic
activity,
arms,
velocity,
activation,
muscles,
as
well
length‐
force‐dependent
walking.
demonstrated
contribute
proprioceptive
regulation
cycle
phase
transitions
stability.
The
obtained
can
guide
development
biologically
accurate
neuromechanical
models
quadrupedal
for
exploring
testing
novel
methods
treatments
central
nervous
system
pathologies
modulating
neural
pathways
controlling
forelimbs/arms.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2023,
Номер
unknown
Опубликована: Дек. 15, 2023
Abstract
When
the
foot
dorsum
contacts
an
obstacle
during
locomotion,
cutaneous
afferents
signal
central
circuits
to
coordinate
muscle
activity
in
four
limbs.
Spinal
cord
injury
disrupts
these
interactions,
impairing
balance
and
interlimb
coordination.
We
evoked
reflexes
by
electrically
stimulating
left
right
superficial
peroneal
nerves
before
after
two
thoracic
lateral
hemisections
placed
on
opposite
sides
of
at
9-13
weeks
interval
seven
adult
cats
(4
males
3
females).
recorded
reflex
responses
ten
hindlimb
five
forelimb
muscles
bilaterally.
After
first
(right
T5-T6)
second
(left
T10-T11)
hemisections,
coordination
fore-
hindlimbs
was
altered
and/or
became
less
consistent.
hemisection,
required
assistance
perform
quadrupedal
locomotion.
Short-latency
homonymous
crossed
largely
remained
unaffected
staggered
hemisections.
However,
mid-
long-latency
both
occurred
frequently
In
muscles,
homolateral
diagonal
response
occurrence
significantly
decreased
all
limbs,
however,
when
present,
short-,
maintained
their
phase-dependent
modulation.
also
observed
reduced
durations
short-latency
inhibitory
extensors
early
hemisection
delayed
ipsilesional
hemisection.
Therefore,
changes
correlated
with
impaired
balance/stability
locomotion
spinal
injury.
Restoring
transmission
could
be
used
as
a
biomarker
facilitate
locomotor
recovery.
Key
points
Cutaneous
afferent
inputs
limbs
obstacle.
Thoracic
communication
between
centers
located
cervical
lumbar
levels,
limb
investigated
nerve
bilaterally,
cats.
showed
loss/reduction
which
balance.
Targeting
pathways
projecting
help
develop
therapeutic
approaches
aimed
restoring
ascending
descending
pathways.
Locomotion
is
controlled
by
spinal
circuits
that
interact
with
supraspinal
drives
and
sensory
feedback
from
the
limbs.
These
sensorimotor
interactions
are
disrupted
following
cord
injury.
The
thoracic
lateral
hemisection
represents
an
experimental
model
of
incomplete
injury,
where
connections
between
brain
abolished
on
one
side
cord.
To
investigate
effects
such
injury
operation
locomotor
network,
we
used
our
computational
cat
locomotion
recently
published
in
eLife
(Rybak
et
al.,
2024)
to
predict
changes
cycle
phase
durations
a
during
treadmill
tied-belt
(equal
left-right
speeds)
split-belt
(unequal
conditions.
In
simulations,
“hemisection”
was
always
applied
right
side.
Based
model,
hypothesized
hemisection,
contralesional
(“intact”,
left)
network
mostly
drives,
whereas
ipsilesional
(“hemisected”,
right)
somatosensory
feedback.
We
then
compared
simulated
results
those
obtained
experiments
adult
cats
before
after
mid-thoracic
same
Our
confirmed
many
predicted
simulations.
show
having
hindlimb
step
slow
belt,
but
not
fast
substantially
reduces
hemisection.
provides
explanations
for
temporal
characteristics
based
altered
circuits,
Previous
studies
established
strong
links
between
morphological
characteristics
of
mammalian
hindlimb
muscles
and
their
sensorimotor
functions
during
locomotion.
Less
is
known
about
the
role
forelimb
morphology
in
motor
outputs
generation
sensory
signals.
Here,
we
measured
46
from
6
cats.
These
included
muscle
attachments,
physiological
cross-sectional
area
(PCSA),
fascicle
length,
etc.
We
also
recorded
full-body
mechanics
EMG
activity
level
overground
treadmill
locomotion
7
16
adult
cats
either
sex,
respectively.
computed
forces
along
with
force-
length-dependent
signals
mapped
onto
corresponding
cervical
spinal
segments.
found
that
patterns
afferent
activities
were
strongly
affected
by
muscle's
moment
arm,
PCSA,
length.
Morphology
shoulder
suggests
distinct
roles
forelimbs
lateral
force
production
movements.
Patterns
long
fibers
(brachioradialis,
extensor
carpi
radialis)
closely
matched
overall
whereas
pattern
biceps
brachii
orientation.
conclude
cat
contributes
substantially
to
locomotor
function,
particularly
control
stability
turning,
rather
than
propulsion.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 20, 2024
Abstract
It
was
suggested
that
during
locomotion,
the
nervous
system
controls
movement
by
activating
groups
of
muscles,
or
muscle
synergies.
Analysis
synergies
can
reveal
organization
spinal
locomotor
networks
and
how
it
depends
on
state
system,
such
as
before
after
cord
injury,
different
conditions,
including
a
change
in
speed.
The
goal
this
study
to
investigate
effects
transection
speed
hindlimb
their
time-dependent
activity
patterns
adult
cats.
EMG
activities
15
muscles
were
recorded
9
cats
either
sex
tied-belt
treadmill
locomotion
at
speeds
0.4,
0.7,
1.0
m/s
recovery
from
low
thoracic
transection.
We
determined
burst
using
cluster
analysis
onset
offset
times
non-negative
matrix
factorization.
found
five
major
each
six
experimental
conditions
(2
states
x
3
speeds).
In
case,
accounted
for
least
90%
variance.
Both
modified
subgroups
composition
activation
selected
However,
these
changes
did
not
modify
general
Based
obtained
results,
we
propose
an
pattern
formation
network
two-level
central
generator
be
tested
neuromechanical
simulations
circuits
controlling
cat
locomotion.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 14, 2024
Locomotion
is
controlled
by
spinal
circuits
that
interact
with
supraspinal
drives
and
sensory
feedback
from
the
limbs.
These
sensorimotor
interactions
are
disrupted
following
cord
injury.
The
thoracic
lateral
hemisection
represents
an
experimental
model
of
incomplete
injury,
where
connections
between
brain
abolished
on
one
side
cord.
To
investigate
effects
such
injury
operation
locomotor
network,
we
used
our
computational
cat
locomotion
recently
published
in
Locomotion
is
controlled
by
spinal
circuits
that
interact
with
supraspinal
drives
and
sensory
feedback
from
the
limbs.
These
sensorimotor
interactions
are
disrupted
following
cord
injury.
The
thoracic
lateral
hemisection
represents
an
experimental
model
of
incomplete
injury,
where
connections
between
brain
abolished
on
one
side
cord.
To
investigate
effects
such
injury
operation
locomotor
network,
we
used
our
computational
cat
locomotion
recently
published
in
eLife
(Rybak
et
al.,
2024)
to
predict
changes
cycle
phase
durations
a
during
treadmill
tied-belt
(equal
left-right
speeds)
split-belt
(unequal
conditions.
In
simulations,
“hemisection”
was
always
applied
right
side.
Based
model,
hypothesized
hemisection,
contralesional
(“intact”,
left)
network
mostly
drives,
whereas
ipsilesional
(“hemisected”,
right)
somatosensory
feedback.
We
then
compared
simulated
results
those
obtained
experiments
adult
cats
before
after
mid-thoracic
same
Our
confirmed
many
predicted
simulations.
show
having
hindlimb
step
slow
belt,
but
not
fast
substantially
reduces
hemisection.
provides
explanations
for
temporal
characteristics
based
altered
circuits,
The Journal of Physiology,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 20, 2024
Abstract
Previous
studies
established
strong
links
between
morphological
characteristics
of
mammalian
hindlimb
muscles
and
their
sensorimotor
functions
during
locomotion.
Less
is
known
about
the
role
forelimb
morphology
in
motor
outputs
generation
sensory
signals.
Here,
we
measured
46
from
six
cats.
These
included
muscle
attachments,
physiological
cross‐sectional
area
(PCSA)
fascicle
length.
We
also
recorded
full‐body
mechanics
EMG
activity
level
overground
treadmill
locomotion
seven
16
adult
cats
either
sex,
respectively.
computed
forces
along
with
force‐
length‐dependent
signals
mapped
onto
corresponding
cervical
spinal
segments.
found
that
patterns
afferent
activities
were
strongly
affected
by
muscle's
moment
arm,
PCSA
Morphology
shoulder
suggests
distinct
roles
forelimbs
lateral
force
production
movements.
Patterns
long
fibres
(brachioradialis,
extensor
carpi
radialis)
closely
matched
overall
length,
whereas
pattern
biceps
brachii
length
afferents
orientation.
conclude
cat
contributes
substantially
to
locomotor
function,
particularly
control
stability
turning,
rather
than
propulsion.
image
Key
points
Little
producing
generating
somatosensory
This
information
needed
understand
contributions
control.
forelimbs,
walking
electromyographic
activity,
arms,
velocity,
activation,
muscles,
as
well
length‐
force‐dependent
walking.
demonstrated
contribute
proprioceptive
regulation
cycle
phase
transitions
stability.
The
obtained
can
guide
development
biologically
accurate
neuromechanical
models
quadrupedal
for
exploring
testing
novel
methods
treatments
central
nervous
system
pathologies
modulating
neural
pathways
controlling
forelimbs/arms.