The human sensorimotor control system has exceptional abilities to perform skillful actions. It allows us to switch effortlessly between strenuous tasks that require brute force, such as lifting a heavy sewing machine, and delicate movements, such as threading a needle in the same machine.
The motor system is able to renew its performance through daily interaction with the different environments. However, problems can also arise that make it difficult for the brain to perform such tasks. To gain insight into the mechanisms of motor control, the Associate Professorship of Neuromuscular Diagnostics, headed by Prof. Dr. David Franklin, provides an overview of the laws of movement that shape everyday human movement through a review paper. The paper was published under the title "Behavioral Motor Performance" in the journal "Comprehensive Physiology". The journal has an impact factor of 8.91.
The article described the most important solutions for each problem of the three stages of the sensorimotor control system, consisting of sensing, planning and acting. Among other things, it looked at how the sensory system and the structure and functioning of the muscles help to overcome deviations and disturbances in motor behavior - with the aim of executing skillful motor performance.
"The idea for this review was to incorporate decades of research into a structure for understanding motor performance," explains Prof. Franklin. "When we examine the topic of motor performance, we mainly find independent research findings describing specific phenomena, observations or invariances, but without an overall structure. Our goal here was to summarize different areas in one review with a computational approach."
The essay summarizes the most important teaching content under twelve key points. Among other things, it explains that human movements can be characterized by a series of invariable processes. These include the interplay of speed and accuracy, smooth sequences and the production of bell-shaped velocity profiles. The brain therefore produces movements with a certain constancy that contribute to optimize certain task goals. These include ensuring stability, reducing error, minimizing energy usage and maximizing rewards. The goal of research in this area is to reverse motor performance and use the trajectory invariances. This allows computations to be made and task goals to be determined that determine sensorimotor control.
Six problems were identified within each of these phases: Nonlinearity, nonstationarity, delays, noise, uncertainty and redundancy. The sensorimotor system has to handle these six problems, each of which can lead to a deterioration in performance. The review identified different mechanisms that could provide solutions to these issue in all three stages of the sensorimotor loop: perceiving, planning and acting, suggesting different ways of implementing them.
"Previous research has often focused on only one of these three stages. However, we now wanted to create a comprehensive overview of this complex topic," says Dr. Raz Leib, Research Associate at the Associate Professorship of Neuromuscular Diagnostics and first author of the publication. "The main purpose of the paper is to give students and those unfamiliar with the field a basic standard and understanding of how it works. With this review, we have compiled the history of the research field up to the current state of research. It's basically educational material, but at a doctorate level."
Prof. Franklin adds: "Ideally, this review will be used by people from all over the world in the future. It's a tool for anyone interested in this field."
To the publication „Behavorial Motor Performance“ in the journal “Comprehensive Physiology”
To the homepage of the Associate Professorship of Neuromuscular Diagnostics
Contact:
Prof. Dr. David Franklin
Associate Professorship of Neuromuscular Diagnostics
Georg-Brauchle Ring 60/62
80992 München
phone: 089 289 24583
e-mail: David.Franklin(at)tum.de
Raz Leib
Associate Professorship of Neuromuscular Diagnostics
Georg-Brauchle Ring 60/62
80992 München
phone: 089 289 24495
e-mail: Raz.Leib(at)tum.de
Text: Romy Schwaiger
Photos: „Comprehensive Physiology”/private