CHIEL, Hillel J; Case Western Reserve University: Neuromechanics of Multifunctionality

How do animals deploy a group of muscles and neurons to generate qualitatively different behaviors? In engineered devices, different functions are cleanly assigned to different sub-components. In contrast, in biological systems, fluid and rapid reconfiguration of both the periphery and nervous system are utilized to generate qualitatively different behaviors. We have studied this phenomenon in the feeding system of the marine mollusk Aplysia californica, which is capable of generating at least three qualitatively different behaviors: biting, swallowing and rejection. The same muscles and motor neurons mediate each of these three behaviors. Changing the timing and phasing of activation of different muscles, which also alters the function of identified motor neurons, mediates the expression of the different behaviors. We are beginning to analyze the interneuronal control that generates multifunctionality by altering the activity of single identified neurons in intact, behaving animals. These results have led to the design of novel, multifunctional biologically-inspired robots.