What will your doctor do with this knowledge to adjust your stroke protocols to counter the invalid synergies that you have post stroke?
http://europepmc.org/abstract/med/26377453
(PMID:26377453)
Department of Electrical Engineering and Computer Sciences, overduin@mit.edu.
UNLABELLED:
Evidence suggests that the CNS uses motor primitives to simplify
movement control, but whether it actually stores primitives instead of
computing solutions on the fly to satisfy task demands is a
controversial and still-unanswered possibility.
Also in contention is whether these primitives take the form of
time-invariant muscle coactivations ("spatial" synergies) or
time-varying muscle commands ("spatiotemporal" synergies).
Here, we examined forelimb muscle patterns and motor cortical spiking
data in
rhesus macaques (
Macaca mulatta)
handling objects of variable shape and size.
From these data, we extracted both spatiotemporal and spatial synergies
using non-negative decomposition.
Each spatiotemporal synergy represents a sequence of muscular or neural
activations that appeared to recur frequently during the
animals'
behavior.
Key features of the spatiotemporal synergies (including their
dimensionality, timing, and amplitude modulation) were independently
observed in the muscular and neural data.
In addition, both at the muscular and neural levels, these
spatiotemporal synergies could be readily reconstructed as sequential
activations of spatial synergies (a subset of those extracted
independently from the task data), suggestive of a hierarchical
relationship between the two levels of synergies.
The possibility that motor cortex may execute even complex skill using
spatiotemporal synergies has novel implications for the design of
neuroprosthetic devices, which could gain computational efficiency by
adopting the discrete and low-dimensional control that these primitives
imply.
SIGNIFICANCE STATEMENT: We studied the motor cortical and forearm muscular activity of
rhesus macaques (
Macaca mulatta)
as they reached, grasped, and carried objects of varied shape and size.
We applied non-negative matrix factorization separately to the cortical
and muscular data to reduce their dimensionality to a smaller set of
time-varying "spatiotemporal" synergies.
Each synergy represents a sequence of cortical or muscular activity that
recurred frequently during the
animals'
behavior.
Salient features of the synergies (including their dimensionality,
timing, and amplitude modulation) were observed at both the cortical and
muscular levels.
The possibility that the brain may execute even complex
behaviors
using spatiotemporal synergies has implications for neuroprosthetic
algorithm design, which could become more computationally efficient by
adopting the discrete and low-dimensional control that they afford.
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