An important general aim of neuroscience is to understand the design principles of brain circuits that control behavior and insects provide ideal models for understanding brain circuitry. Their brains are comprised of relatively few cells, and they have well-defined behavior patterns. The present research project will analyze how specific brain cells are organized into functional circuits controlling behavior in a group of related insects. The comparison of brain circuits in closely related species will provide understanding of the general principles by which brains are engineered by nature to control behavior. In previous work funded by NSF, it was established that specific brain cells ("DMIs") of some insects trigger evasive responses to antennal contact from predators. The antennae are under visual guidance, apparently in part by a brain cell referred to as "DCMD". Preliminary evidence suggests that in some insects the DCMD acts as a visual sensor and the DMIs control directional movements so that as an ensemble these cells form a circuit to coordinate directional motor behaviors specific to each insect species. A specific hypotheses will be tested: that the visual sensing part of this circuit has remained fairly constant across different insects, but that the way in which the circuit delivers information to movement systems has changed to account for the differing behavioral requirements of each species. This hypothesis will be tested by mapping the structure of the cells, recording their responses to an array of sensory cues, and recording how they signal during behavior. The cells also will be selectively inactivated. A diverse group of students will receive neuroscience training during the project. Finally, the studies will lead to new tools such as a database of identified brain cells for researchers and this information could be used for designing "biologically inspired" circuits for applications in robotics and for building intelligent interfaces between people and machines.
