Neural Control of Movement Laboratory

Muscle Activity

Muscle activity and force perception

Nonlinearity and redundancy of the musculoskeletal system, as well as noise and delays of sensory inputs, challenge sensorimotor integration processes. However, humans have a remarkable ability to produce efficient goal-directed movements and make precise perceptual inference. It has been proposed 1,2 that to simplify these processes during perceptual decision making, the central nervous system (CNS) select patterns of movements aimed to maximize the sampling of task-related sensory input, i.e., active sensing. Accordingly, active perception would rely on coupling between movements and patterns of movement-generated sensory inflow. We are exploring the relation between action and perception by investigating whether and to what extent lower-level organization of motor control contributes to active perception. Specifically, by combining electromyography, psychophysics and statistical modeling we have shown that force perception depends, to a high extent, on the coordinated recruitment of a small groups of muscles, i.e., muscle synergies, engaged to counteract the same force3 (Fig. 3).

 

Figure 3. Experimental set-up and data analysis to quantify the amount of perceptual variance explained by the across trials modulation of few patterns of muscle synergy. From: d’Avella et al. (2003).

 

For more information on these projects contact: Simone Toma

References

  1. d’Avella, A., Saltiel, P. and Bizzi, E. (2003). Combinations of muscle synergies in the construction of a natural motor behavior. Nature Neuroscience.
  2. Bizzi, E., d’Avella, A., Saltiel, P., and Tresch, M. (2002). Modular organization of spinal motor systems. Neuroscientist.
  3. Toma S. and Santello M. (2019). Motor modules account for active perception of force. Scientific Report.