Determine whether the proposed degeneracy distribution extends to multi-joint systems

Determine whether the distribution of degeneracy and redundancy proposed for a single-joint, two-muscle neuromechanical system holds in multi-joint systems with biarticular muscles and coordinated force feedback.

Background

The paper’s conceptual argument is based on a simplified neuromechanical model containing one joint and two antagonist muscles. The authors identify this simplification as useful for isolating the proposed degeneracy gap, but note that multi-joint systems introduce biarticular muscles and additional coordination mechanisms.

Whether the same distribution of degeneracy across the sensorimotor hierarchy persists when these multi-joint interactions and force-feedback mechanisms are included is explicitly left unresolved.

References

Multi-joint systems introduce biarticular muscles and a coordination in which force feedback might play a particular role, and we do not know whether the distribution we describe holds there.

— Degeneracy along the sensorimotor hierarchy: motor control within a framework larger than redundancy  (2609.11325 - Paclet et al., 10 Sep 2026) in Section 8, paragraph beginning “The argument has relied on a spinal circuit”

The use of neurons without action potentials likewise rules out a source of variability, whose relation to degeneracy has not been examined.

— Degeneracy along the sensorimotor hierarchy: motor control within a framework larger than redundancy  (2609.11325 - Paclet et al., 10 Sep 2026) in Section 8, paragraph beginning “The argument has relied on a spinal circuit”

We also do not know how degeneracy is distributed over the behavior map. The fifth prediction of section 5 poses the alternative: degeneracy highest at the limits of the reachable domain, where a demanding task mobilizes the whole circuit, or highest at its center, where constraints are loose and admissible command sets are many.

— Degeneracy along the sensorimotor hierarchy: motor control within a framework larger than redundancy  (2609.11325 - Paclet et al., 10 Sep 2026) in Section 8, paragraph beginning “We also do not know how degeneracy”