The coding of airborne-sound and vibration signals in bimodal ventral-cord neurons of the grasshopperTettigonia cantans

Summary In grasshoppers, the auditory and vibrational senses converge on the same ventral-cord neurons. All neurons in the ventral cord that discharge impulses in response to either airborne-sound or vibration stimuli also receive synaptic inputs from the other sensory system. The latter elicit either subthreshold excitation or inhibition.The coding of the conspecific song in the responses of most ventral-cord neurons ofTettigonia cantans is considerably improved when the stimulus consists not of simulated natural sounds alone, but of such sounds together with either maintained vibration or vibration matched to the temporal structure of the song.Stridulating tettigoniids produce both airborne and substrate-conducted sound. Thus the perception of airborne sound and vibration, and their simultaneous processing in individual ventral-cord neurons, may be of fundamental importance — not only in localizing a nearby sound source, but also in facilitating the recognition of conspecific signals.Abbreviations SNS simulated natural songThe work was supported by the Deutsche Forschungsgemeinschaft, as part of the program Neurale Mechanismen des Verhaltens (Ka 498/1)We are grateful to Dr. M.A. Biederman-Thorson for the translation of the text and to Mrs. A. Scheiding for technical help.