Thesis (M.S.)--Western Washington University, 2010. / Includes bibliographical references (leaves 27-34). Also issued online.

Thesis (Ph.D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 95-100)

Thesis (Honors)--College of William and Mary, 2009. / Includes bibliographical references (leaves 34-37). Also available via the World Wide Web.

Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02

In this thesis, I investigated computational and neural mechanisms underlying foraging-related behavior in humans. A consideration of the ecological constraints under which mammalian behavior first evolved guided my investigation of learning and decision-making in frontal cortex. When engaged in foraging, animals have to figure out how profitable their actions are and whether it is better to continue foraging in their current environment or to switch to an alternative. They have to track the reward income of their actions over time and also take into account that the actions of other foraging animals have a direct influence on their reward income (Chapter 1). Based on these observations, I looked at similar types of behavior in humans using computational modeling and functional magnetic resonance imaging. I studied how people evaluate the profitability of their actions over time (Chapter 2). Dorsal anterior cingulate cortex carried a detailed representation of the value of the current foraging action, which was influenced by reward memories with different time constants (Chapter 3). Tracking the reward income of one's actions is not only important in order to learn about the profitability of the environment, it can also inform estimates of one's own and other people's abilities. Ability estimates can be used in a direct way to predict the reward outcome that the actions of one's own self and others will have. I found that people learn about their own and others' abilities in a rational manner but also that ability estimates of self and other were partly confused with each other, depending on whether subjects cooperated or competed with each other (Chapter 4). The confusion effect is reflected in Brodmann area 9 activity indicating that area 9 integrates self and other related information. Perigenual anterior cingulate tracked the ability estimates for oneself, suggesting that it might compute the success expectation of an action independent of particular features of the environment (Chapter 5). In sum, different subregions of medial frontal cortex carried different types of action-related value representations that can guide decision-making.

<p>In recent years, many studies have reported that the tactile spatial acuity of blind participants is enhanced relative to that of sighted participants, but it is unclear what factors drive this enhancement. In the series of three psychophysics studies (of tactile spatial acuity) presented in this thesis, we attempted to tease apart two hypotheses explaining tactile spatial acuity enhancement in the blind: visual deprivation and tactile experience. To measure tactile spatial acuity in these studies, we used a grating orientation task. In the first study (Chapter 2), we found that blind participants outperformed sighted participants, but only on body parts where tactile experience is presumably greater in blind than in sighted participants (i.e., fingertips, not lips); we found additionally that blind participants’ tactile acuity correlated with their Braille reading behaviour (e.g., style, frequency of reading). In the second study (Chapter 3), we found that visual deprivation of sighted participants for periods up to 110 minutes did not enhance their sense of touch. In the third study (Chapter 4), we found that extensive training on a tactile task can substantially improve sighted participants’ sense of touch. The findings from our three studies thus provide consistent support for the hypothesis that tactile experience, but not visual deprivation, drives tactile spatial acuity enhancement in the blind.</p> / Doctor of Philosophy (PhD)

Wong, Muk Yan. / Thesis submitted in: October 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 88-93). / Abstracts in English and Chinese. / Introduction --- p.1 / Chapter Chapter One: --- What is a Cognitive Theory of Emotion? / Chapter Section One: --- How are emotion and cognitive elements related? --- p.5 / Chapter Section Two: --- What kind of cognitive element is involved? --- p.13 / Chapter Chapter Two: --- Challenges from Neuroscience / Chapter Section One: --- The Quick-and-Dirty Route Argument --- p.31 / Chapter Section Two: --- The Backward Masking Argument --- p.35 / Chapter Section Three: --- The Brain Development Argument --- p.38 / Chapter Chapter Three: --- Possible Responses from the Cognitive Theory of Emotion / Chapter Section One: --- Response to the Quick-and-Dirty Route Argument --- p.44 / Chapter Section Two: --- Response to the Backward Masking Argument --- p.56 / Chapter Section Three: --- Response to the Brain Development Argument --- p.64 / Chapter Chapter Four: --- Reflection on the Conversation between Neuroscience and Philosophy / Chapter Section One: --- Conceptual Questions Versus Empirical Questions --- p.71 / Chapter Section Two: --- Competition for the Authoritative Interpretation of Common Understanding --- p.74 / Chapter Section Three: --- Explanatory Power as the Final Aim of Both Philosophy and Neuroscience --- p.77 / Conclusion --- p.82 / Bibliography --- p.85

Risky alcohol use is a major health concern among college students, with 40.1% reporting binge drinking (5 or more drinks in one occasion) and 14.4% reporting heavy drinking (binge drinking on 5 or more occasions) in the past month. Risky alcohol use is thought to be the result of a complex interplay between genes, biological processes, and other phenotypic characteristics. Understanding this complex relationship is further complicated by known phenotypic heterogeneity in the development of alcohol use. Developmental studies have suggested two pathways to risky alcohol use, characterized by externalizing and internalizing characteristics, respectively. However, the underlying biological processes that differentiate these pathways are not fully understood. Neuroimaging studies have assessed reward sensitivity, emotion reactivity, and behavioral inhibition using fMRI and separately demonstrate associations in externalizing and internalizing disorders more broadly. In addition, previous genetic studies have found associations between specific polymorphisms and these externalizing and internalizing subtypes. Therefore, we sought further characterize the biological influences on binge drinking subtypes through the following specific aims: 1) determine the genetic relationship between externalizing and internalizing characteristics in binge drinkers, 2) test whether externalizing and internalizing binge drinkers show differences in brain activation in response to tasks measuring emotion reactivity, reward sensitivity, and behavioral inhibition. In order to achieve these aims, we conducted a series of genetic analyses assessing differences in overall SNP-based heritability and specific associated variants between the externalizing and internalizing subtypes. There were a few variants that reached genome-wide significance, the most notable being a cluster of SNPs associated with internalizing characteristics that were located in the RP3AL gene. In a subset of these binge drinking young adults, brain activation was measured on tasks assessing behavioral inhibition, reward sensitivity, and emotion reactivity. We found some preliminary differences with regard to emotion reactivity, that suggest internalizing binge drinkers are more reactive to faces overall but have blunted reaction to sad faces compared to externalizers. These findings provide an initial step to better understanding the underlying biology between the classic externalizing and internalizing alcohol use subtypes, which has the potential to elucidate new subtype specific targets for prevention and intervention.

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Applied Mathematics. / Typescript. Includes bibliographical references (leaves 225-239). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR46003

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