Multimodal sensory integration in the strike-feeding behaviour of predatory fishes

The search for useful model systems for the study of sensory processing in vertebrate nervous systems has resulted in many neuroethological studies in vestigating the roles played by a single sensory modality in a given behavi our. However, behaviours relying solely upon information from one sensory m odality are relatively rare. Animals behaving in a complex, three-dimension al environment receive a large amount of information from external and inte rnal receptor arrays. Clearly, the integration of sensory afference arising from different modalities into a coherent 'gestalt' of the world is essent ial to the behaviours of most animals. In the last several years our labora tory team has examined the roles played by the visual and lateral line sens ory systems in organizing the feeding behaviour of two species of predatory teleost fishes, the largemouth bass, Micropterus salmoides, and the muskel lunge, Esox masquinongy. The free-field feeding behaviours of these fishes were studied quantitatively in intact animals and compared to animals in wh ich the lateral line and visual systems had been selectively suppressed. Al l groups of animals continued to feed successfully, but significant differe nces were observed between each experimental group, providing strong clues as to the relative role played by each sensory system in the organization o f the behaviour. Furthermore, significant differences exist between the two species. The differences in behaviour resulting when an animal is deprived of a given sensory modality reflect the nature of central integrative sens ory processes, and these behavioural studies provide a foundation for furth er neuroanatomical and physiological studies of sensory integration in the vertebrate central nervous system.