Meeting Abstract

S6.3-3  Sunday, Jan. 5 14:30  Control and dynamics of movement in biology II: what does control theory have to offer integrative biology? COWAN, N. J.*; DANIEL, T. L.; Johns Hopkins Univ.; Univ. of Washington ncowan@jhu.edu

Control theory was developed with the objective of guiding manmade systems, not analyzing biological ones. Thus, it is natural to question its potential value (or not) in the analysis of the evolved—rather than designed—“wetware” that seems to be at the reigns of biological systems. Worse yet, with an animal, it is not even clear what is “controller” and what is “plant”: both brain and body co-evolved. On the other hand, it is unquestionable that biological systems have a dynamic character, and so it is reasonable to argue that it is better to stick with the generality of dynamical systems theory (which has a long tradition in analyzing existing systems) instead of specializing to the subdiscipline of control theory (invented for synthesis, not analysis). Nevertheless, here, we argue that the somewhat teleological approach of applying control theoretic analysis to biological systems serves to enhance our understanding of the challenges that evolution, development, neural plasticity, etc all have in “tuning” a biological system to achieve certain “goals”. In so doing, we must realize that feedback is not the purview of one part of the system alone; for example, during movement, it is not solely the nervous system responsible for properties like stability, but rather the musculoskeletal system itself has also been tuned to simplify control, and thus holds just as many of the secrets. But, with this important proviso in mind, fundamental features such as stability, robustness, controllability, observability, etc, which are all constructs of the field of control theory, are essential in developing a comprehensive understanding of integrative biological systems.