Dendritic mechanisms of auditory stream segregation in an insect

• Published in: The Journal of the Acoustical Society of America 2009-10, Vol.126 (4_Supplement), p.2292-2292
• Main Author: Schul, Johannes
• Format: Article
• Language: English
• Subjects: Tettigoniidae
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.3249393

Auditory stream segregation (AudSS) is the process of grouping the auditory scene into coherent perceptual objects. We recently described AudSS in an insect: In Neoconocephalus katydids, a first-order auditory interneuron (TN-1) segregates bat cries with slow pulse rates from conspecific communication signals with fast pulse rates. This insect system provides a powerful opportunity to study neuronal mechanisms of AudSS in an identified neuron with testable behavioral function. TN-1 adapts rapidly to fast pulse rates and responses are completely suppressed. However, if a slow pulse rate of sufficiently different carrier frequency is presented simultaneously, TN-1 responds reliably to the slow rate pulses. The suppression of the fast pulse rate on TN-1, i.e., the critical component of AudSS, is caused by two dendritic processes intrinsic to TN-1. The first mechanism is transient and likely calcium mediated, while the second mechanism is sustained throughout the stimulation and likely sodium mediated. TN-1 responses to slow pulse rates, occurred when the slow and fast pulse rate were transmitted by different groups of receptor cells, which project onto different regions of the TN-1 dendrite. Based on these results, we propose a mechanism of dynamic dendritic compartmentalization to underlie AudSS in the katydid TN-1.