@article {58047, title = {Phonotactic steering and representation of directional information in the ascending auditory pathway of a cricket}, year = {2020}, abstract = {

Directional hearing is crucial for animals depending on acoustic signals to locate a mate. We focused on crickets to explore the reliability of directional information forwarded to the brain by the ascending auditory interneuron AN1, which is crucial for phonotactic behavior. We presented calling song from -45\° to +45\° in steps of 3\°, and compared the phonotactic steering of females walking on a trackball with the directional responses of AN1. 40\% of females showed good steering behavior and changed their walking direction when the speaker passed the body\´s longitudinal axis. The bilateral latency difference between right and left AN1 responses was small and may not be reliable for auditory steering. In respect to spike count, all AN1 recordings presented significant bilateral differences for angles larger than \±18\°, yet 35\% showed a mean significant difference of 1-3 AP/Chirp when the frontal stimulus deviated by 3\° from their length axis. For small angles some females had a very similar AN1 activity forwarded to the brain, but the accuracy of their steering behavior was substantially different. Our results indicate a correlation between directional steering and the response strength of AN1, especially for large angles. The reliable steering of animals at small angles would have to be based on small bilateral differences of AN1 activity, if AN1 is the only source providing directional information. We discuss if such bilateral response difference at small angles can provide a reliable measure to generate auditory steering commands descending from the brain, as pattern recognition is intensity independent.

}, keywords = {AN1 interneuron, binaural differences, reliability, spike response, surface electrodes}, doi = {10.1152/jn.00737.2019}, url = {https://www.physiology.org/doi/10.1152/jn.00737.2019https://www.physiology.org/doi/pdf/10.1152/jn.00737.2019}, author = {Lv, Mingyue and Zhang, Xinyang and Hedwig, Berthold} } @article {57660, title = {Feedforward discharges couple the singing central pattern generator and ventilation central pattern generator in the cricket abdominal central nervous system}, year = {2019}, abstract = {

We investigated the central nervous coordination between singing motor activity and abdominal ventilatory pumping in crickets. Fictive singing, with sensory feedback removed, was elicited by eserine-microinjection into the brain, and the motor activity underlying singing and abdominal ventilation was recorded with extracellular electrodes. During singing, expiratory abdominal muscle activity is tightly phase coupled to the chirping pattern. Occasional temporary desynchronization of the two motor patterns indicate discrete central pattern generator (CPG) networks that can operate independently. Intracellular recordings revealed a sub-threshold depolarization in phase with the ventilatory cycle in a singing-CPG interneuron, and in a ventilation-CPG interneuron an excitatory input in phase with each syllable of the chirps. Inhibitory synaptic inputs coupled to the syllables of the singing motor pattern were present in another ventilatory interneuron, which is not part of the ventilation-CPG. Our recordings suggest that the two centrally generated motor patterns are coordinated by reciprocal feedforward discharges from the singing-CPG to the ventilation-CPG and vice versa. Consequently, expiratory contraction of the abdomen usually occurs in phase with the chirps and ventilation accelerates during singing due to entrainment by the faster chirp cycle.

}, keywords = {Abdominal ventilation, Central pattern generation, Corollary discharge, Fictive singing, Motor systems coordination}, doi = {10.1007/s00359-019-01377-7}, url = {http://link.springer.com/10.1007/s00359-019-01377-7}, author = {Sch{\"o}neich, Stefan and Hedwig, Berthold} } @article {47895, title = {Evolution of a Communication System by Sensory Exploitation of Startle Behavior}, journal = {Current Biology}, volume = {25}, year = {2015}, month = {Jan-12-2015}, pages = {3245 - 3252}, abstract = {

New communication signals can evolve by sensory exploitation if signaling taps into preexisting sensory biases in receivers [1 ;\  2]. For mate attraction, signals are typically similar to attractive environmental cues like food [3; 4; 5 ;\  6], which amplifies their attractiveness to mates, as opposed to aversive stimuli like predator cues. Female field crickets approach the low-frequency calling song of males, whereas they avoid high-frequency sounds like predatory bat calls [7]. In one group of crickets (Eneopterinae: Lebinthini), however, males produce exceptionally high-frequency calling songs in the range of bat calls [8], a surprising signal in the context of mate attraction. We found that female lebinthines, instead of approaching singing males, produce vibrational responses after male calls, and males track the source of vibrations to find females. We also demonstrate that field cricket species closely related to the Lebinthini show an acoustic startle response to high-frequency sounds that generates substrate vibrations similar to those produced by female lebinthine crickets. Therefore, the startle response is the most likely evolutionary origin of the female lebinthine vibrational signal. In field crickets, the brain receives activity from two auditory interneurons; AN1 tuned to male calling song controls positive phonotaxis, and AN2 tuned to high-frequency bat calls triggers negative phonotaxis [9 ;\  10]. In lebinthine crickets, however, we found that auditory ascending neurons are only tuned to high-frequency sounds, and their tuning matches the thresholds for female vibrational signals. Our results demonstrate how sensory exploitation of anti-predator behavior can evolve into a communication system that benefits both senders and receivers.

}, issn = {09609822}, doi = {10.1016/j.cub.2015.10.064}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0960982215013585}, author = {ter Hofstede, Hannah M. and Sch{\"o}neich, Stefan and Tony Robillard and Hedwig, Berthold} } @inbook {15579, title = {The Cricket Auditory Pathway: Neural Processing of Acoustic Signals}, booktitle = {The Cricket as a Model Organism}, year = {2017}, pages = {155 - 167}, publisher = {Springer Japan}, organization = {Springer Japan}, address = {Tokyo}, isbn = {978-4-431-56476-8}, doi = {10.1007/978-4-431-56478-210.1007/978-4-431-56478-2_11}, url = {http://link.springer.com/10.1007/978-4-431-56478-2}, author = {Gerald S. Pollack and Hedwig, Berthold} }