Biology Ph.D. Dissertations

Title

Neural and Behavioral Responses to Complex Odor Stimuli Using Crayfish as a Model System

Date of Award

2005

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Biological Sciences

First Advisor

Paul Moore

Abstract

The physical environment in which animals live has a profound impact on the sensory information they receive and how they respond behaviorally to that information. This is particularly true for chemical cues that are transported through moving fluids. Natural habitats provide a complex environment that structures and alters chemical cues such as food and predator, as well as mating pheromones as they are transported through changing habitats. For example, a natural river bed consists of a mixture of different substrates over which water flows. These different substrates exhibit different levels of roughness elements that alter the turbulence structure of the flow over these areas. Because the distribution of chemical cues or odor plumes is highly influenced by turbulence structure of a moving fluid, you would expect changes in the available chemical information as an odor plume is transported over different substrates (i.e. habitats) within a river. Changes in the structure and availability of relevant chemical information can overwhelmingly affect behavioral strategies used to orient toward or avoid a particular odor cue. These behavioral strategies in turn are mediated by the underlying neural processing of external environmental stimuli. In crayfish, orientation behavior has been thought to be particularly influenced by the spatial and temporal fluctuations of turbulent odor plumes, especially by changes in the intermittency, duration and concentration of individual odor filaments. The focus of this compendium of work is to provide a comprehensive investigation into the influence that physical odor plume dynamics in natural habitats have on neural processing and orientation behavior. The overall objective of this collection of investigations is to understand how the physical environment structures complex information and how the nervous system has evolved to process this information to ultimately mediate behaviors.

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