02361nas a2200181 4500008004100000245011800041210006900159520167900228653002001907653002501927653001601952653001901968653002301987100001602010700001902026700002102045856011302066 2020 eng d00aPhonotactic steering and representation of directional information in the ascending auditory pathway of a cricket0 aPhonotactic steering and representation of directional informati3 a

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.

10aAN1 interneuron10abinaural differences10areliability10aspike response10asurface electrodes1 aLv, Mingyue1 aZhang, Xinyang1 aHedwig, Berthold uhttps://www.physiology.org/doi/10.1152/jn.00737.2019https://www.physiology.org/doi/pdf/10.1152/jn.00737.201902056nas a2200169 4500008004100000245016200041210006900203520138200272653002601654653003101680653002401711653002001735653003101755100002301786700002101809856005601830 2019 eng d00aFeedforward discharges couple the singing central pattern generator and ventilation central pattern generator in the cricket abdominal central nervous system0 aFeedforward discharges couple the singing central pattern genera3 a

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.

10aAbdominal ventilation10aCentral pattern generation10aCorollary discharge10aFictive singing10aMotor systems coordination1 aSchöneich, Stefan1 aHedwig, Berthold uhttp://link.springer.com/10.1007/s00359-019-01377-702397nas a2200181 4500008004100000022001300041245008400054210006900138260001600207300001600223490000700239520181000246100002902056700002302085700002002108700002102128856006602149 2015 eng d a0960982200aEvolution of a Communication System by Sensory Exploitation of Startle Behavior0 aEvolution of a Communication System by Sensory Exploitation of S cJan-12-2015 a3245 - 32520 v253 a

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.

1 aHofstede, Hannah, M. ter1 aSchöneich, Stefan1 aRobillard, Tony1 aHedwig, Berthold uhttp://linkinghub.elsevier.com/retrieve/pii/S096098221501358500476nas a2200133 4500008004100000020002200041245007200063210006700135260002600202300001400228100002400242700002100266856005500287 2017 eng d a978-4-431-56476-800aThe Cricket Auditory Pathway: Neural Processing of Acoustic Signals0 aCricket Auditory Pathway Neural Processing of Acoustic Signals aTokyobSpringer Japan a155 - 1671 aPollack, Gerald, S.1 aHedwig, Berthold uhttp://link.springer.com/10.1007/978-4-431-56478-2