Fig. 6. A summary model of function in turn behavior. Chemotactile afferents of oral veil are conceived as being integrated in an interneuronal layer that averages amplitude and laterality of chemotactile input. The output of the interneuronal layer is translated to the turn motor network through a switch mechanism regulated by the animal's appetitive state and memory of experience. The switch acts to invert the laterality of the output to the turn motor network to result in orienting or avoidance turns.