THE STOMATOGASTRIC NERVOUS-SYSTEM - A FORMAL APPROACH

A discrete mathematical formalism (d-space) which is specifically desi gned to investigate discrete aspects of behavior is applied to the for egut of decapod crustacea. This approach differs from continuous model ing techniques in that the analysis determines a structure in which th e observed behavior of the foregut is constrained. A notation for the implementation of the formalism is developed as well as a coordinate s ystem natural to the functioning of the gastric mill. The formalism is used to organize previous observations that suggest potential courses of further experimental investigation. A detailed analysis of observe d chewing modes of the gastric mill is presented, along with a discuss ion of the overall organization of the interrelationships between thes e modes. The investigation also addresses the relationship between beh avioral modes of a pyloric muscle found in the shrimp Palaemon. Two al ternative hypotheses are presented to describe the relationship of the behavioral components of the gastric mill: an interlaced control sche me in which the components are freely exchanged, and a top-down contro l system where the chewing modes are rigidly separated into packages. Flow through regions of state space in time is found to be important i n determining the relations between the discrete behavioral components . The behavior of the foregut, like that of other motor control system s, is shown to fit naturally into the d-space formalism.