From pages 30-31 of the conference program (link).
Goodman, J. M.
Schaffelhofer, S.
Scherberger, H.
Neurons in the frontoparietal cortical grasping network respond
during both the execution and observation of an action. This observation
has been used to support numerous theories linking motor control and
cognition but remains poorly understood at the neuronal population
level. To address this, we use chronic multi-electrode arrays to record
simultaneously from neuronal populations in the macaque primary motor
(M1), premotor (F5), and posterior parietal (AIP) cortices as animals
either grasp a variety of different objects or observe a human subject
doing the same. We find a lack of distinct functional neuronal classes
in any of these cortical areas; instead, neurons exhibit a continuum of
preferences for action and observation. The lack of clear neuron classes
affirms that the link between action and observation may indeed be
better understood in the framework of neuronal state space. Using
targeted dimensionality reduction techniques, we find dimensions of
neural activity that are shared between action and observation contexts,
which decrease in prominence from AIP to F5 to M1. However, this shared
activity does not include a shared representation of grip type, as
assessed using classification methods that allow for response scaling
and latency differences between the two contexts. We also fit linear
dynamical systems to these data and fail to find a common dynamical
structure underlying the disparate grip representations between action
and observation. Activity during observation therefore lacks congruence
with the precise grip-specific representations and dynamics seen during
action. These results suggest that the link between action observation
and action execution is weaker than anticipated in the frontoparietal
network.