Corollary discharge inhibition of wind - sensitive cercal 1 giant interneurons in the singing field cricket

26 27 Crickets carry wind-sensitive mechanoreceptors on their cerci, which in 28 response to the airflow produced by approaching predators trigger escape reactions 29 via ascending giant interneurons (GIs). Males also activate their cercal system by air 30 currents generated due to the wing movements underlying sound production. Singing 31 males still respond to external wind stimulation, but are not startled by the self32 generated airflow. To investigate how the nervous system discriminates sensory 33 responses to self-generated and external airflow we intracellularly recorded wind34 sensitive afferents and ventral GIs of the cercal escape pathway in fictively singing 35 crickets, a situation lacking any self-stimulation. 36 GI spiking was reduced whenever cercal wind stimulation coincided with 37 singing motor activity. The axonal terminals of cercal afferents showed no indication 38 of presynaptic inhibition during singing. In two ventral GIs, however, a corollary 39 discharge inhibition occurred strictly in phase with the singing motor pattern. Paired 40 intracellular recordings revealed that this inhibition was not mediated by the activity of 41 the previously identified corollary discharge interneuron (CDI) that rhythmically 42 inhibits the auditory pathway during singing. Cercal wind stimulation, however, 43 reduced the spike activity of this CDI by postsynaptic inhibition. 44 Our study reveals how precisely timed corollary discharge inhibition of ventral 45 GIs can prevent self-generated airflow from triggering inadvertent escape responses 46 in singing crickets. The results indicate that the responsiveness of the auditory and 47 wind-sensitive pathway is modulated by distinct CDIs in singing crickets and that the 48 corollary discharge inhibition in the auditory pathway can be attenuated by cercal 49 wind stimulation. 50 51