Sequential Filtering Processes Shape Feature Detection in Crickets: A Framework for Song Pattern Recognition

Abstract

Intraspecific acoustic communication requires filtering processes and feature detectors in the auditory pathway of the receiver for the recognition of species-specific signals. Insects like acoustically communicating crickets allow describing and analysing the mechanisms underlying auditory processing at the behavioral and neural level. Female crickets approach male calling song, their phonotactic behavior is tuned to the characteristic features of the song, such as the carrier frequency and the temporal pattern of sound pulses. Data from behavioral experiments and from neural recordings at different stages of processing in the auditory pathway lead to a concept of serially arranged filtering mechanisms. These encompass a filter for the carrier frequency at the level of the hearing organ, and the pulse duration through phasic onset responses of afferents and reciprocal inhibition of thoracic interneurons. Further, processing by a delay line and coincidence detector circuit in the brain leads to feature detecting neurons that specifically respond to the species-specific pulse rate, and match the characteristics of the phonotactic response. This same circuit may also control the response to the species-specific chirp pattern. Based on these serial filters and the feature detecting mechanism, female phonotactic behavior is shaped and tuned to the characteristic properties of male calling song.

Organization of the Drosophila larval visual circuit

“…An interesting aspect resulting from tonic inhibition of VPNs during constant light stimulation is what happens when the light intensity decreases (OFF response). Some neurons subject to tonic inhibition can have a rebound of activity when inhibition is lifted ( Marder and Bucher, 2001 ; Hedwig, 2016 ). If, via this mechanism, VPNs were to increase their activity upon a decrease in light intensity, they would be encoding an OFF response.…”

Roles of Octopamine and Dopamine Neurons for Mediating Appetitive and Aversive Signals in Pavlovian Conditioning in Crickets

“…Indeed, it can be stated that crickets are one of the best insect models for pharmacological analysis of learning and memory (Mizunami et al, 2013 ). Third, much information on the brain and behavior of crickets has been obtained as crickets have been used in diverse neuroethological studies (Stevenson and Schildberger, 2013 ; Hedwig, 2016 ). We first deal with the recent debate about whether appetite and aversive signals are conveyed by octopamine and dopamine neurons, respectively, as has been suggested in honey bees and crickets, or whether both appetitive and aversive signals are mediated by dopamine neurons, as has been suggested in fruit-flies.…”

Adaptations during maturation in an identified honeybee interneuron responsive to waggle dance vibration signals

“…Furthermore, the strength of postinhibitory rebound doubled during maturation. Since inhibition coupled with postinhibitory rebound has been suggested to play an important role in processing temporal signals in insects (Ai et al 2018) and specifically in detecting temporal features (Hedwig 2016; Alluri et al 2016; Naud et al 2015; Yamada et al 2018), our results indicate improved detection of information encoded in the temporal features of waggle dance sounds in forager honeybees.…”