Sound processing in the cricket brain: evidence for a pulse duration filter.

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.

Tonotopic Ca dynamics and sound processing in auditory interneurons of the bush-cricket Mecopoda elongata.

Two auditory neurons, TN-1 and ON-1, in the bush-cricket, Mecopoda elongata, have large dendritic arborisations which receive excitatory synaptic inputs from tonotopically organised axonal terminals of auditory afferents in the prothoracic ganglion. By combining intracellular microelectrode recording with calcium imaging we demonstrate that the dendrites of both neurons show a clear Ca signal in response to broad-frequency species-specific chirps. Due to the organisation of the afferents frequency specific auditory activation should lead to local Ca increases in their dendrites.

Response properties of spiking and non-spiking brain neurons mirror pulse interval selectivity.

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.

An auditory-responsive interneuron descending from the cricket brain: a new element in the auditory pathway.

Crickets receive auditory information from their environment via ears located on the front legs. Ascending interneurons forward auditory activity to the brain, which houses a pattern recognition network for phonotaxis to conspecific calling songs and which controls negative phonotaxis to high-frequency sound pulses. Descending brain neurons, however, which are clearly involved in controlling these behaviors, have not yet been identified.

The central organisation of courtship and rivalry behaviour in Gryllus bimaculatus (deGeer) as revealed by lesions of abdominal connectives.

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.