Binaural comparison of intensity is the basis of sound localisation in crickets. Two features of the neural response, response strength and response latency, can encode intensity. Therefore, binaural difference in spike-count and in latency can be used as sound localisation cues. In this work, I investigate the effects of ultrasound intensity and pulse-rate on sound localisation cues as well as the directionality of the response in an ultrasound-sensitive interneuron, AN2. I found that habituation, a decline in neural response, decreases binaural cues encoded in spike-count but increases the cues encoded in first-spike latency. In addition, binaural spike-count and latency difference encode the exact location of ultrasound pulses with similar reliability. As crickets are submitted to habituating stimuli in their natural environment, latency difference is a more useful cue than spike-count difference to locate an ultrasound, although comparison of these results with a previous study suggests that crickets use predominantly binaural difference in spike-count to localise ultrasound.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33835 |
| Date | January 2002 |
| Creators | Samson, Annie-Helene. |
| Contributors | Pollack, Gerald S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001871503, proquestno: MQ78953, Theses scanned by UMI/ProQuest. |
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