Publications by authors named "Berthold Hedwig"

The auditory system of female crickets allows them to specifically recognize and approach the species-specific male calling song, defined by sound pulses and silent intervals. Auditory brain neurons form a delay-line and coincidence detector network tuned to the pulse period of the male song. We analyzed the impact of changes in pulse duration on the behavior and the responses of the auditory neurons and the network.

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In the bispotted field cricket auditory pulse pattern recognition of the species-specific calling song is based on a delay-line and coincidence detection network, established by the activity and synaptic connections of only 5 auditory neurons in the brain. To obtain a more detailed understanding of the network and the dynamic of the neural activity over time we analyzed the response properties of these neurons to test patterns, in which the pulse duration was kept constant while the duration of specific pulse intervals was systematically altered. We confirm that the ascending interneuron AN1 and the local interneuron LN2 copy the structure of the pulse pattern, however with limited resolution at short pulse intervals, further evident in downstream neural responses.

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Behaviour is rooted in the organization and activity of an animal's nervous system. As male crickets use their front wings for sound production, the neural circuits underlying singing had been suggested to be housed in the thoracic ganglia. However, systematic lesion experiments of the CNS demonstrated that the abdominal nervous system is essential for their calling song behaviour.

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When the amplitude modulation of species-specific acoustic signals is distorted in the transmission channel, signals become difficult to recognize by the receiver. Tolerant auditory pattern recognition systems, which after having perceived the correct species-specific signal transiently broaden their acceptance of signals, would be advantageous for animals as an adaptation to the constraints of the environment. Using a well-studied cricket species, , we analysed tolerance in auditory steering responses to '' chirps, mimicking a signal distorted by the transmission channel, and control '' chirps by employing a fine-scale open-loop trackball system.

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Article Synopsis
  • Researchers explore how neural networks in crickets evolve to recognize diverse mating songs, focusing on the computational flexibility of these networks.
  • Using electrophysiological recordings and computational models, they demonstrate that crickets can recognize various pulse patterns in mating songs.
  • The findings reveal that this flexibility allows for phenotypic diversity, supporting evolutionary adaptations for energy efficiency and robustness in communication.
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We recorded the wing movements and sound signals during the production of calling, rivalry, and courtship song in the bispotted field cricket Gryllus bimaculatus. Recordings confirm that salient sound pulses during calling and rivalry song are generated during the closing movements of the wings. Wing movements for calling and rivalry song start from an elevated wing position and are performed with a very similar opening-closing movement, indicating that both types of songs may be generated by the same neuronal network.

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For crickets, which approach singing males by phonotaxis, the female choosiness hypothesis postulates that young females should be more selective of male calling song patterns than older individuals. However, there is no information about the behavioural preferences of females over their complete adulthood. We analysed phonotaxis in female Gryllus bimaculatus throughout their entire adult lifetime and measured the impact of sound amplitude, carrier frequency and the temporal pattern of test songs on their auditory response.

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Although crickets move their front wings for sound production, the abdominal ganglia house the network of the singing central pattern generator. We compared the effects of specific lesions to the connectives of the abdominal ganglion chain on calling song activity in four different species of crickets, generating very different pulse patterns in their calling songs. In all species, singing activity was abolished after the connectives between the metathoracic ganglion complex and the first abdominal ganglion A3 were severed.

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Chirping male crickets combine a 30 Hz pulse pattern with a 3 Hz chirp pattern to drive the rhythmic opening-closing movements of the front wings for sound production. Lesion experiments suggest two coupled modular timer-networks located along the chain of abdominal ganglia, a network in A3 and A4 generating the pulse pattern, and a network organized along with ganglia A4-A6 controlling the generation of the chirp rhythm. We analyzed neurons of the timer-networks and their synaptic connections by intracellular recordings and staining.

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Authors would like to update one of the references which went incorrect in the original publication and the corrected version is updated here.

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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.

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We studied bilateral processing in the auditory ON neurons of crickets using reversible cold-deactivation of the hearing organs by means of Peltier elements. Intracellular recordings of the neurons' activity in response to acoustic stimuli were obtained, while either the ipsilateral or the contralateral hearing organ was cold-deactivated. Afferent activity was abolished at a temperature of approximately 10°C.

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The evolution of species-specific song patterns is a driving force in the speciation of acoustic communicating insects. It must be closely linked to adaptations of the neuronal network controlling the underlying singing motor activity. What are the cellular and network properties that allow generating different songs? In five cricket species, we analyzed the structure and activity of the identified abdominal ascending opener interneuron, a homologous key component of the singing central pattern generator.

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The integration of stimuli of different modalities is fundamental to information processing within the nervous system. A descending interneuron in the cricket brain, with prominent dendrites in the deutocerebrum, receives input from three sensory modalities: touch of the antennal flagellum, strain of the antennal base, and visual stimulation. Using calcium imaging, we demonstrate that each modality drives a Ca increase in a different dendritic region.

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The evolutionary loss of sexual traits is widely predicted. Because sexual signals can arise from the coupling of specialized motor activity with morphological structures, disruption to a single component could lead to overall loss of function. Opportunities to observe this process and characterize any remaining signal components are rare, but could provide insight into the mechanisms, indirect costs and evolutionary consequences of signal loss.

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We used suction electrodes to reliably record the activity of identified ascending auditory interneurons from the anterior surface of the brain in crickets. Electrodes were gently attached to the sheath covering the projection area of the ascending interneurons and the ringlike auditory neuropil in the protocerebrum. The specificity and selectivity of the recordings were determined by the precise electrode location, which could easily be changed without causing damage to the tissue.

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Acoustic communication requires filter mechanisms to process and recognize key features of the perceived signals. We analysed such a filter mechanism in field crickets (), which communicate with species-specific repetitive patterns of sound pulses and chirps. A delay-line and coincidence-detection mechanism, in which each sound pulse has an impact on the processing of the following pulse, is implicated to underlie the recognition of the species-specific pulse pattern.

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The delivery of tracers into populations of neurons is essential to visualize their anatomy and analyze their function. In some model systems genetically-targeted expression of fluorescent proteins is the method of choice; however, these genetic tools are not available for most organisms and alternative labeling methods are very limited. Here we describe a new method for neuronal labelling by electrophoretic dye delivery from a suction electrode directly through the neuronal sheath of nerves and ganglia in insects.

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Animals need to flexibly respond to stimuli from their environment without compromising behavioural consistency. For example, female crickets orienting toward a conspecific male's calling song in search of a mating partner need to stay responsive to other signals that provide information about obstacles and predators. Here, we investigate how spontaneously walking crickets and crickets engaging in acoustically guided goal-directed navigation, i.

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Decoding the neural basis of behaviour requires analysing how the nervous system is organised and how the temporal structure of motor patterns emerges from its activity. The stereotypical patterns of the calling song behaviour of male crickets, which consists of chirps and pulses, is an ideal model to study this question. We applied selective lesions to the abdominal nervous system of field crickets and performed long-term acoustic recordings of the songs.

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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.

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Mechanoelectrical transduction of acoustic signals is the fundamental process for hearing in all ears across the animal kingdom. Here, we performed in vivo laser-vibrometric and electrophysiological measurements at the transduction site in an insect ear (Mecopoda elongata) to relate the biomechanical tonotopy along the hearing organ to the frequency tuning of the corresponding sensory cells. Our mechanical and electrophysiological map revealed a biomechanical filter process that considerably sharpens the neuronal response.

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