Thesis (M. S.)--Psychology, Georgia Institute of Technology, 2007. / Schumacher, Eric, Committee Chair ; Corballis, Paul, Committee Member ; Jacko, Julie, Committee Member.

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No description available.

Thesis (M.S.)--Ohio University, August, 2009. / Title from PDF t.p. Includes bibliographical references.

This thesis provides a history of the sense of touch in modern Britain. Seeking out fugitive intimacies and incidental brushes of lover and stranger alike, it argues that far from being a natural constant, what, how, and why people touched, and what they felt when they did, has a history. Through five case studies of different domains - the mind sciences, visual impairment, public transport, law, and commercialized leisure - it explores how these uses changed, and how they transformed Britons' understandings and experiences of their bodies. Both as a practice and a metaphor, from making space on the bus to keeping 'in touch', touch established the distinctions that Britons made between their bodies and the world and themselves and others. In doing so, touch crucially shaped histories of law, labour relations, scientific experiment, education, and love in the early twentieth century. But it also reformulated the very distinctions of selfhood - distinctions of inner self and outer body, person and thing - on which our accounts of modernity are based. By tracing a history of touch, then, this thesis turns touch into a means of critique. It challenges histories of modernity for which selfhood is a substance rather than produced only through particular social relationships. But it also proposes a new way of thinking about selfhood as an immanent relationship the self has with itself through use of the body. Through historically specific ways of touching, early twentieth-century Britons shaped not only their experience of themselves as bodies, but also the boundaries defining them as selves. Their selfhood was, in short, what they did with the body through touch. By exploring the history of touch between 1870 and 1960, this thesis therefore offers an alternative account of British modernity and a way of re-examining histories of selfhood within and beyond modern Britain.

M.A. (Psychology) / Please refer to full text to view abstract

Physical and intellectual differences in the home environment of Xhosa and White children suggested that the interaction of touch and vision in situations of sensory conflict and the development of dominance may be different in children from these homes. Children aged 5-13 years were tested on apparatus which created a conflict of tactual and visual judgement about the perceived size of the stimulus. Xhosa and White subjects performed similarly except when only tactual judgement was allowed and the Xhosa group were less influenced by touch. The study concludes that for children touch and vision contribute equally to the resolution of sensory conflict when both senses are active in size-judgements and when only one mode is allowed for judging then the resolution is biased towards this mode. This outcome is different from that of experiments with adults and has implications for theories derived from them.

Previous research has shown a large genetic influence over personality traits, especially sensation seeking. One gene thought to influence this behavioural trait is the dopamine-4-receptor gene (DRD4), in which variants have been associated with sensation seeking and novelty seeking in some, but not all studies. The inconsistencies between studies may be due to heterogeneity in both the behaviours and the populations being assessed. Some studies included only males and few studies have a priori analyzed males and females separately. SS has been associated with high-risk sports, including skiing; however, this is the first study to address the possibility that genetics may play a role in individuals’ inclination towards SS in sport. Using the Contextual Sensation Seeking Questionnaire for Skiing (CSSQ-S), developed and validated for this study, and the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ), levels of SS in males and females were analyzed in association with the alleles of a polymorphism in the dopamine-4-receptor, -521 C/T (a C or a T at position -521). Behavioural analysis of skiers (N = 200) revealed a significant correlation (r²= .506, p < .001) between skier behaviour (CSSQ-S) and skier personality score (ZKPQ) for sensation seeking. Genotype analysis (N = 74) revealed allele frequencies of .58 C and .42 T and an over-representation of the C allele was found in the population of skiers compared with a general Caucasian population (p < .01). In females, a significant association was found between the homozygous C/C genotype and high levels of contextual skiing SS behaviour (N = 36, p = .006, η² = .2), along with a non-significant trend between ZKPQ impulsive SS scores and the alleles of -521 C/T (p = .086). No association, however, was found in males (N=38, p ZKPQ = .473, p CSSQ-S = .345). This study supports the hypothesis that alleles of the DRD4 -521 C/T polymorphism are associated with context-specific SS behaviours, however only in females. Social pressures may differentially influence male and female sensation-seeking behaviour which may explain the lack of association in males, though this hypothesis requires further investigation. / Education, Faculty of / Kinesiology, School of / Graduate

The encoding of olfactory information starts from the interaction between odorant molecules and olfactory sensory neurons (OSNs). In mouse, one mature olfactory sensory neuron (OSN) almost exclusively expresses one out of ~1,000 odorant receptors (ORs). The relationship between odorants and ORs is promiscuous: one odorant can activate multiple ORs and one OR can be activated by many odorants. This combinatorial olfactory coding scheme is fundamental, but not sufficient to fully understand the peripheral encoding of odor mixtures. Almost all naturally-occurring smells consist of many different odorous compounds; for example, the perception of rose is composed of (-)-cis-rose oxide, beta-damascenone, bata-ionone and many other odorants. It is well appreciated in psychology and perfumery that different components in an odor blend can affect each other, producing modulation effects. However, these effects are often considered to be the results of higher center processing, while odor interactions at the peripheral level have not been comprehensively measured. To evaluate peripheral neuronal responses to odor blends, it is necessary to profile the response patterns of a large population of OSNs while the responses of each individual OSN can be resolved. Conventionally, this has been achieved by imaging OSNs acutely dissociated from the olfactory epithelium with a regular epi-fluorescent microscope. In Chapter 2 of this thesis, such method was utilized to characterize the response patterns of three groups of bio-isosteres. This study reveals that OSNs discriminate odors primarily based on their topological properties rather than chemical properties. Chapter 3 investigates the modulation effects of Hedione, a chemical that has been widely used in perfumery for 60 years. Hedione is psychophysically known as an enhancer that brings up the volume of floral and citrus odors, but the underlying mechanism remains largely unknown. Our study showed that Hedione could both enhance and inhibit odor responses in peripheral neurons, with inhibition being the dominant effect. Moreover, dose-dependent analyses have shown that odorant receptors with lower binding affinity are more prone to inhibition, leading to the hypothesis that Hedione may act as a weak antagonist, which highlights the scent of the leading compound through contrast enhancement. However, the cell imaging method in Chapter 2 and 3 was limited by the low throughput (200 cells per field of view) and cell damage during digestion. Utilizing a new advance in microscopy, Swept Confocally Aligned Planar Excitation (SCAPE), I was able to perform 3D volumetric imaging on the intact olfactory epithelium of OMP-CRE+/-GCaMP6f-/- mice with a perfused half-head preparation. This method is capable of recording over 10,000 OSNs simultaneously with high spatial and temporal resolution. The process of establishing the imaging protocol and data analysis pipeline has been detailed in Chapter 4. Chapter 5 characterizes OSN responses to odor blends using the SCAPE microscopy. A large number of responding cells showed inhibited or enhanced responses to odor mixtures compared with responses to each individual component. Eight structurally and perceptually distinct chemicals were tested, all shown to act as antagonists or enhancers to some extent. Compared with a monotonically additive coding scheme, the presence of widespread modulation effects could diversify the output, thereby increasing the capacity of the olfactory system to distinguish complex odor mixtures. Taken together, these results show that olfactory information is subject to widespread modulation in the olfactory epithelium. This unusual complexity at the primary receptor level implies an information coding strategy different from those utilized by visual and acoustic systems, where complex interactions among stimuli only occur at higher levels of processing. Further experiments are needed to explain the mechanisms at the molecular level and to link peripheral neuronal responses to psychophysics and behavior.

A neuron’s function depends critically on the shape, size, and territory of its dendritic field. We have only recently begun to understand how diverse dendritic arbors are built and how the morphology and territory of these arbors support diverse neural functions. In this thesis, I use the Drosophila larval peripheral nervous system (PNS) as a model for studying these questions, as these neurons are very amenable to genetic manipulation and in vivo imaging. First, I examined the relationship between dendritic fields and sensory activity in the proprioceptive neurons of the body wall. In collaboration with Elizabeth Hillman’s lab, we used a high-speed volumetric microscopy technique, Swept Confocally Aligned Planar Excitation (SCAPE) microscopy, to simultaneously image the dendrite deformation dynamics and sensory activity of body wall neurons in crawling Drosophila larvae. We imaged a set of proprioceptive neurons with diverse dendrite morphologies and territories, revealing that each neuron subtype responds in sequence during crawling. These activities could conceivably provide a continuum of position encoding during locomotion. Activity timing is related to the dynamics of each neuron’s dendritic arbors, suggesting arbor shape and targeting endow each proprioceptor with a specific role in monitoring body wall deformation. Furthermore, our results provide new insights into the body-wide activity dynamics of the proprioceptive system, which will inform models of sensory feedback during locomotion. To investigate how dendritic arbors are built to support sensory function, I focused on proprioceptive (class I) and touch-sensing (class II-III) dendritic arborization (da) neurons. Proprioceptive and touch-sensing dendrite territories tend to target non-overlapping, neighboring, areas of the body wall. How is territory coverage specified during development, and how does this coverage support a specific sensory function? Ablation studies indicate that repulsive interactions between heterotypic dendrites are not required for territory patterning. Instead, dendrite boundaries correlate with Anterior (A)-Posterior (P) compartment boundaries in the underlying epidermal substrate: proprioceptive class I dendrites target the P compartment, while touch-sensing dendrites tend to avoid that region. I found that genetic expansion of the P compartment leads to expansion of class I proprioceptive dendrites, suggesting compartmentalized epidermal cues instruct dendrite targeting. Furthermore, SCAPE imaging revealed that the P compartment coincides with a major body wall fold that occurs during crawling. These results support a model in which dendrite targeting by compartment cues reliably tunes neurons for predictable stimuli on the body wall: proprioceptive dendrites target areas that bend predictably during crawling, while touch-sensing dendrites could be avoiding those areas to be tuned for external mechanosensory stimuli. To investigate the molecular identity of the substrate cues guiding the compartmental organization of dendrites, I tested candidate cues and sought new potential cues. I first tested cues that are known to be expressed in a compartmental fashion (Hedgehog and EGFR pathways). Interestingly, the overall dendrite territory footprint of class I proprioceptive cells is unaffected by known compartment cues. To reveal new candidates, I performed cell sorting and RNA sequencing. I identified 290 cell surface and secreted molecules with differential expression in the A and P compartments. I provide initial findings from a knockdown and misexpression screen testing the role of these candidates for class I and class III territory patterning. Taken together, these results provide new insights into how dendritic fields are patterned to support proper neural function.