Multimodal sensory integration in the heliothine moth.

摘要

Gathering and integrating sensory information are crucial to create the cohesive representation of the environment that is required for an organism to make appropriate behavioral and physiological decisions. For many animals, olfactory cues provide a rich source of information that can be used to determine the location of food or potential mates, to communicate either within a species or with individuals of another species, and to detect dangerous situations. This information is integrated with inputs from other senses to complete a perception of the environment. In particular, males of many species of moths rely upon both olfactory and visual information to make behavioral decisions associated with locating potential mates. Visual and olfactory cues are integrated in the moth brain to regulate mate-finding flight behaviors. In this research, these moth behaviors were utilized as a starting point towards identifying neuron-level processes for integrating sensory inputs. The first portion of the study investigated the upwind flight behavior of male Heliothis virescens during changing visual conditions that simulated a shifting wind. The moths regulated the flow of visual information to continue to fly in the perceived upwind direction, even in the absence of real changes in the wind direction. In the second portion of the study, the integration of information within the olfactory system was investigated electrophysiologically. A subset of olfactory projection neurons was found to respond to pheromone blend cues required for upwind flight. The morphology of these neurons included a more direct route to the descending pathways from the brain to the flight motor than previously described for pheromone responsive olfactory projection neurons. The third portion of the study sought to identify neurons within the brain that responded to both visual and olfactory cues. The neurons recorded were found to be highly variable both physiologically and morphologically but allow for the proposal of a model for sensory integration in the moth brain. This research utilized a range of experimental techniques, including behavioral assays, histology, and electrophysiology. Importantly, the results provided insights into the neurons involved in multimodal sensory integration and the flight behaviors that are the output of this sensory pathway.