Meeting Abstract

P3.156  Sunday, Jan. 6  Extracellular recordings of wing campaniform sensilla of Manduca sexta demonstrate encoding properties similar to intracellular recordings of haltere neurons. HOWELL, DB*; DICKERSON, BH; DYHR, JP; SPONBERG, SN; DANIEL, TL; University of Washington howelld@uw.edu

Insects rely on an array of sensory organs to maintain stable flight. For the hawkmoth Manduca sexta, both visual and antennal mechanosensory systems have established roles in flight control. The wings, however, are also imbued with a rich set of mechanosensory structures (campaniform sensilla). Wings experience forces that arise not only from aerodynamic lift and thrust, but also from inertial processes resulting from wing flapping and body maneuvers or perturbations. Sensory information from the wings, therefore, could provide information about body inertial dynamics. Thus, wings may function as both actuators and sensors. Previous intracellular recordings have shown that the campaniform sensilla can encode wing bending with frequencies exceeding 200 Hz, sufficient for reporting rapid inertial events. But intracellular methods limit the number of cells that can be studied. To examine the encoding dynamics of multiple campaniform sensilla simultaneously, we developed methods for recoding multi-unit extracellular activity while mechanically oscillating the wing with a white noise stimulus. Using spike sorting algorithms, we identified single neuron responses within the multi-unit recordings and constructed spike triggered ensembles and the corresponding spike triggered averages (STA), i.e. the average mechanical stimulus that precedes a spike. A subpopulation of extracellular STAs from three animals were similar to those observed in prior intracellular studies of haltere and wing nerves having waveforms with peak deformation stimulus occurring approximately 5 ms prior to spikes. We suggest that this neural information can be used to detect perturbations in the body trajectory, giving wings both sensor and actuator roles.