Meeting Abstract

52.1  Thursday, Jan. 5  Shaken, not static: multimodal processing in the antenna of the hawkmoth Manduca sexta. DICKERSON, BH*; DANIEL, TL; RIFFELL, JA; University of Washington bdicker@uw.edu

Insect antennae are integral to navigation through complex environments, serving a host of sensory modalities including chemical, mechanical, auditory, and thermal stimuli. Indeed, no other single sensory structure is involved in as many modalities as the antenna. In particular, the antennae of the hawkmoth Mandua sexta can detect different olfactory cues and their passive oscillation during flight enables the antennae to act as inertial sensors. The oscillations of the antennae, which are responsible for mechanosensory input, are determined by the antennae’s flexural stiffness and mass distribution. Antennal oscillations may also modulate the boundary layer dynamics, affecting chemical flux and, in turn, chemosensory input. There exists, therefore, a potential interaction between mechanosensory and chemosensory input for a single sensory structure mediated by biomechanical processes. This interaction may also be mediated by dual input from primary afferents to local interneurons in the brain during sensory processing. Using multichannel electrophysiological measurements, we explored this interaction to test whether oscillation of the antennae affects neural representation of odor in the antennal lobe of Mandua sexta. Results show that the combination of antennal oscillation and odor presentation increases peak firing rates during the stimulus cycle by 28.0 ±17.4% in three of seven cells, while the remaining four cells show a decrease of 47.5 ±18.8% in response. Together, these data point to two potential mechanisms for sensory synergies: one mediated by biomechanical processes; the other by neural processing.