Thèse - Faculté de médicine de Paris. / "Index bibliographique": p. [89]-90.

Thesis (Ph.D.) -- University of Western Sydney, 1999. / Thesis submitted for the degree of Doctor of Philosophy. Includes bibliographical references (leaves 279-318).

Thesis (Ph. D.)--University of Sydney, 2009. / Includes graphs and tables. Includes list of publications and three published articles co-authored with others. Title from title screen (viewed June 9, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Psychology. Degree awarded 2009; thesis submitted 2008. Includes bibliographical references. Also available in print form.

Thesis (Ph. D.)--Cornell University. / "Reprint from the American Journal of Psychology, vol. X, no. 1."

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Insects rely heavily on olfaction to locate food, find mates and sense danger. Odorant stimuli in their natural environment often consist of mixtures of several chemical compounds, and stimulus concentration in air fluctuates rapidly and unpredictably. Despite the complex nature of natural odorant stimuli, odor identity can be encoded by insects' olfactory systems very quickly. How this can be achieved is still an open area of study. Here, I ask two specific questions: 1. Are the olfactory responses to mixture stimuli qualitatively different from those to pure chemical compounds and are such differences relevant to olfactory coding? and 2. Which types of temporal spike information can potentially be useful for olfactory coding? To address the first question, I extended a standard receptor model to mixtures. Through mathematical analysis of the extended model, I found that first-spike latencies are shorter and activity patterns are more stable across concentrations in olfactory receptor neurons for mixtures than for pure odorants. I then built a computational model of the early olfactory system of honey bees and showed that the above-mentioned mixture effects can also be observed deeper in insects' brain. These results suggest that mixtures can be more efficiently identified by insects than pure odorants. To address the second question, I developed mathematical methods to approximate the probability distribution of the first-spike latency of a leaky integrate-and-fire neuron upon receiving an external input signal with auto-correlated background noise. The approximation is excellent for a wide range of sizes and shapes of the signal, even when the dynamical time scale of the signal is comparable to that of membrane integration. The methods allow efficient evaluation of how reliable certain correlation patterns of spikes from multiple neurons would be formed after a sensory stimulus is applied, which indicates whether these patterns could carry information about the stimulus.

The sense of smell is a primal sense for humans as well as animals.In everyday life the smells encountered are composed of dozens, even hundreds of odors; few arise from a single odorant. Enormous numbers of odors occur due to the vast variation in the concentration, size and structure of odorant molecules that makes olfaction differ from simpler visual or auditory dimensions. Accordingly, little is known about the ways in which changes in molecular structure and concentration of individual odorants change odor quality. Also, currently not much is understood about synergism/antagonism, how one odorant masks or suppresses another in mixtures and there is no method for predicting which odor will be suppressed. The two main objectives of this thesis were to determine whether a part of a molecular structure rather than the whole structure plays a key role in odor quality and whether a key part of a molecule can be used to choose antagonists for that odorant. For this study three classes of musks and two potential antagonists were used. The results of the study are discussed in some detail. It is concluded that future studies of the importance of molecular structure in mixture interactions require substantially more information on the relation between structure and odor quality to allow systematic studies to be developed. In summary the two hypotheses investigated were not supported by the results. Importantly, however, they do support the view that it is likely that odor quality is dependent on the whole structure of an odorant not a single feature. / Master of Science (Hons)

The purpose of the research conducted in this thesis was two-fold. First, it was to examine the impact of temporal processing on the capability of participants to determine the order of perception and the identity of components in mixtures of three tastants. Secondly, it was to determine if interaction occurs between the two modalities of taste and olfaction, and to determine the capacity of humans to identify the components of taste-odour mixtures. Overall, the results of the studies provide new information about the capacity of humans to analyse chemosensory mixtures, which can be applied in studies of the impact of real food components. / Master of Science (Hons)

Thesis (Ph. D.)--University of Chicago, The Divinity School, Aug. 2003. / Includes bibliographical references. Also available on the Internet.

Odour recognition memory was studied in 49 patients with unilateral temporal lobe excision, and 20 control subjects. Odours were presented monorhinally to explore any asymmetry in performance between nostrils, and to test for hemispheric differences between patients with excision from the right versus the left temporal lobe. Testing was by a 2-alternative, forced-choice procedure, immediately after presentation and 24 hours later. A discrimination test was carried out at the conclusion of the memory test, and nondiscriminated odours were excluded from the final memory scores. The contribution of the hippocampus to odour memory was investigated by dividing patient groups according to the size of hippocampal excision. The memory test showed that only patients with excision from the left temporal lobe that included a large hippocampal removal were impaired after 24 hours. The discrimination test revealed deficits only for patients with right temporal lobectomy, and only in the right nostril.