Meeting Abstract

P2-111  Sunday, Jan. 5  Nociceptive strike behavior in Manduca sexta is mediated by multimodal sensory neurons CARON, DP*; SCIBELLI, AE; TRIMMER, BT; Tufts University, Medford, MA; Tufts University, Medford, MA; Tufts University, Medford, MA daniel.caron@tufts.edu

The caterpillar Manduca sexta produces a highly stereotyped “strike” behavior in response to noxious thermal or mechanical stimuli to the posterior abdomen. This rapid movement is targeted to the site of the stimulus, but the identity of the nociceptive sensory neurons is currently unknown. It is also not known if both mechanical and thermal stimuli are detected by the same neurons. Here we show that the likelihood of a strike increases with the strength of the stimulus. Recordings from nerves innervating the body wall show that sensory neuron spike activity increases rapidly in response to noxious stimuli. Mapping the sensitivity of the body wall to strong thermal stimuli reveals a broad receptive field suggesting a role of the multi-dendritic neurons. Both mechanical and thermal stimuli to the dorsal body wall activate the same spiking unit. Rapidly repeated thermal or mechanical stimuli cause depression of the response which is generalized across modalities. These results demonstrate that individual neurons in the body wall can respond to both strong thermal and mechanical stimuli.