3 Electrophysiology and Optophysiology of Complex Brain Functions in Insects

Abstract

The search for the neural mechanisms of behavior calls for research strategies that reach beyond establishing correlates between sensory or motor performances and neural activities: Ideally, recordings will be made while the animal performs behavioral acts from neural structures that control and create these acts. Even simple forms of behavioral acts are usually not expressed in a natural form when physiological measures are collected from identified neurons or sets of multiple units from known neural nets. More complicated forms of behavior—including changes in behavior as a consequence of experience and memory processing—are even more difficult to trace to their neural processes, because they require a motivated and attentive animal which expresses its changed behavior under physiological recording conditions. Insects come with small brains, and thus one would expect even more complications to reach beyond vague correlations, because permanently implanted recording sets cannot be fixed to the head of a freely moving animal, as is possible in rats or monkeys. However, the higher proportion of stereotyped behavioral routines and the particular design of the central nervous system in insects, with its unique and identifiable neurons, compensate for the size disadvantage and offer a range of possibilities in these endeavors that make these small animals highly attractive for neuroscience.

The insect model system I focus on is the honeybee (Apis mellifera). Honeybees are social animals with the most sophisticated community structure of all insects. Like other social animals, they require a range of complex faculties. Since they do not survive...