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Indiana University-Purdue University Indianapolis (IUPUI) / The primary objectives of this thesis are (1) to discuss the current understanding of phenomena associated with, proposed mechanisms of, and suggested treatments for amputation related pain, (2) to describe the software developed for analyzing results of a clinical study for the treatment of phantom limb pain (PLP), (3) to discuss the methods for a multi-center trial by the EPIONE consortium along with presenting preliminary results, and (4) to discuss the methods and results of a case study involving a new therapy modality for alleviating PLP. Each objective has been expanded into a chapter as described below. Chapter 1 serves as a literature review introducing the topic of amputation, associ- ated phenomena, and proposed mechanisms. The chapter also discusses the currently available treatments and the instruments used to measure PLP. Key topics include the definition of PLP, the prevalence of PLP, current treatment options for PLP, and experimental measurement of PLP. The final objective of this chapter is to introduce topics related to the investigation paradigm utilized for the studies following in Chapter 4 and Chapter 5. Therefore, a minor emphasis has been put on surface electrical stimulation (SES) and operant conditioning. As with any multi-center clinical study, coordination is key. Chapter 2 introduces the common clinical protocol (CCP) and methods of analysis for the clinical trials conducted by the EPIONE consortium. In order to analyze results in an automated fashion, a software tool was developed. This tool, the EPIONE Extraction Program (EEP) along with its extension the Group Analysis Module (GAM), is the focus of Chapter 3. A high-level overview of the requirements, process flow, and software testing are described. This chapter also discusses the methods of analysis for several self-report instruments used to determine effect size in Chapter 4 and Chapter 5. The outputs of the software tools make up the results presented and described in these chapters. In addition to the details included in Chapter 3, supplemental information is available in Appendix A and Appendix B, which are the detailed User Guides for the EEP and GAM. Chapter 4 reviews the pilot study data conducted by the EPIONE consortium. The primary and two secondary instruments used for analysis are discussed. This chapter provides a brief overview of results from the group. Each clinical site used slightly different variations of a common clinical protocol to better understand what effectively drives alleviation of PLP and to allow comparison of results. The work done at Indiana University - Purdue University Indianapolis (IUPUI) represents a small part of several other universities involved in the EPIONE consortium. Chapter 5 focuses on a case study at IUPUI with a more in-depth review of data collected throughout the study period. Using SES, we seek to reverse cortical reorganization by giving meaningful stimuli through existing circuitry. In this chapter the present work is discussed by introducing a case study in detail with an analysis of psychophysical data.

This thesis provides an overview of work conducted to investigate human spatial hearing in situations involving multiple concurrent sound sources. Much is known about spatial hearing with single sound sources, including the acoustic cues to source location and the accuracy of localisation under different conditions. However, more recently interest has grown in the behaviour of listeners in more complex environments. Concurrent sound sources pose a particularly difficult problem for the auditory system, as their identities and locations must be extracted from a common set of sensory receptors and shared computational machinery. It is clear that humans have a rich perception of their auditory world, but just how concurrent sounds are processed, and how accurately, are issues that are poorly understood. This work attempts to fill a gap in our understanding by systematically examining spatial resolution with multiple sound sources. A series of psychophysical experiments was conducted on listeners with normal hearing to measure performance in spatial localisation and discrimination tasks involving more than one source. The general approach was to present sources that overlapped in both frequency and time in order to observe performance in the most challenging of situations. Furthermore, the role of two primary sets of location cues in concurrent source listening was probed by examining performance in different spatial dimensions. The binaural cues arise due to the separation of the two ears, and provide information about the lateral position of sound sources. The spectral cues result from location-dependent filtering by the head and pinnae, and allow vertical and front-rear auditory discrimination. Two sets of experiments are described that employed relatively simple broadband noise stimuli. In the first of these, two-point discrimination thresholds were measured using simultaneous noise bursts. It was found that the pair could be resolved only if a binaural difference was present; spectral cues did not appear to be sufficient. In the second set of experiments, the two stimuli were made distinguishable on the basis of their temporal envelopes, and the localisation of a designated target source was directly examined. Remarkably robust localisation was observed, despite the simultaneous masker, and both binaural and spectral cues appeared to be of use in this case. Small but persistent errors were observed, which in the lateral dimension represented a systematic shift away from the location of the masker. The errors can be explained by interference in the processing of the different location cues. Overall these experiments demonstrated that the spatial perception of concurrent sound sources is highly dependent on stimulus characteristics and configurations. This suggests that the underlying spatial representations are limited by the accuracy with which acoustic spatial cues can be extracted from a mixed signal. Three sets of experiments are then described that examined spatial performance with speech, a complex natural sound. The first measured how well speech is localised in isolation. This work demonstrated that speech contains high-frequency energy that is essential for accurate three-dimensional localisation. In the second set of experiments, spatial resolution for concurrent monosyllabic words was examined using similar approaches to those used for the concurrent noise experiments. It was found that resolution for concurrent speech stimuli was similar to resolution for concurrent noise stimuli. Importantly, listeners were limited in their ability to concurrently process the location-dependent spectral cues associated with two brief speech sources. In the final set of experiments, the role of spatial hearing was examined in a more relevant setting containing concurrent streams of sentence speech. It has long been known that binaural differences can aid segregation and enhance selective attention in such situations. The results presented here confirmed this finding and extended it to show that the spectral cues associated with different locations can also contribute. As a whole, this work provides an in-depth examination of spatial performance in concurrent source situations and delineates some of the limitations of this process. In general, spatial accuracy with concurrent sources is poorer than with single sound sources, as both binaural and spectral cues are subject to interference. Nonetheless, binaural cues are quite robust for representing concurrent source locations, and spectral cues can enhance spatial listening in many situations. The findings also highlight the intricate relationship that exists between spatial hearing, auditory object processing, and the allocation of attention in complex environments.

This thesis provides an overview of work conducted to investigate human spatial hearing in situations involving multiple concurrent sound sources. Much is known about spatial hearing with single sound sources, including the acoustic cues to source location and the accuracy of localisation under different conditions. However, more recently interest has grown in the behaviour of listeners in more complex environments. Concurrent sound sources pose a particularly difficult problem for the auditory system, as their identities and locations must be extracted from a common set of sensory receptors and shared computational machinery. It is clear that humans have a rich perception of their auditory world, but just how concurrent sounds are processed, and how accurately, are issues that are poorly understood. This work attempts to fill a gap in our understanding by systematically examining spatial resolution with multiple sound sources. A series of psychophysical experiments was conducted on listeners with normal hearing to measure performance in spatial localisation and discrimination tasks involving more than one source. The general approach was to present sources that overlapped in both frequency and time in order to observe performance in the most challenging of situations. Furthermore, the role of two primary sets of location cues in concurrent source listening was probed by examining performance in different spatial dimensions. The binaural cues arise due to the separation of the two ears, and provide information about the lateral position of sound sources. The spectral cues result from location-dependent filtering by the head and pinnae, and allow vertical and front-rear auditory discrimination. Two sets of experiments are described that employed relatively simple broadband noise stimuli. In the first of these, two-point discrimination thresholds were measured using simultaneous noise bursts. It was found that the pair could be resolved only if a binaural difference was present; spectral cues did not appear to be sufficient. In the second set of experiments, the two stimuli were made distinguishable on the basis of their temporal envelopes, and the localisation of a designated target source was directly examined. Remarkably robust localisation was observed, despite the simultaneous masker, and both binaural and spectral cues appeared to be of use in this case. Small but persistent errors were observed, which in the lateral dimension represented a systematic shift away from the location of the masker. The errors can be explained by interference in the processing of the different location cues. Overall these experiments demonstrated that the spatial perception of concurrent sound sources is highly dependent on stimulus characteristics and configurations. This suggests that the underlying spatial representations are limited by the accuracy with which acoustic spatial cues can be extracted from a mixed signal. Three sets of experiments are then described that examined spatial performance with speech, a complex natural sound. The first measured how well speech is localised in isolation. This work demonstrated that speech contains high-frequency energy that is essential for accurate three-dimensional localisation. In the second set of experiments, spatial resolution for concurrent monosyllabic words was examined using similar approaches to those used for the concurrent noise experiments. It was found that resolution for concurrent speech stimuli was similar to resolution for concurrent noise stimuli. Importantly, listeners were limited in their ability to concurrently process the location-dependent spectral cues associated with two brief speech sources. In the final set of experiments, the role of spatial hearing was examined in a more relevant setting containing concurrent streams of sentence speech. It has long been known that binaural differences can aid segregation and enhance selective attention in such situations. The results presented here confirmed this finding and extended it to show that the spectral cues associated with different locations can also contribute. As a whole, this work provides an in-depth examination of spatial performance in concurrent source situations and delineates some of the limitations of this process. In general, spatial accuracy with concurrent sources is poorer than with single sound sources, as both binaural and spectral cues are subject to interference. Nonetheless, binaural cues are quite robust for representing concurrent source locations, and spectral cues can enhance spatial listening in many situations. The findings also highlight the intricate relationship that exists between spatial hearing, auditory object processing, and the allocation of attention in complex environments.

Perception is strongly influenced by our expectations, especially under situations of uncertainty. A growing body of work suggests that perception is akin to Bayesian Inference in which expectations can be viewed as ‘prior’ beliefs that are combined via Bayes’ rule with sensory evidence to form the ‘posterior’ beliefs. In this thesis, I aim to answer open questions regarding the nature of expectations in perception, and, in particular, what the limits of complexity and specificity in developing expectations are, and how expectations of different temporal properties develop and interact. First, I conducted a psychophysical experiment to investigate whether human observers are able to implicitly develop distinct expectations using colour as a distinguishing factor. I interleaved moving dot displays of two different colours, either red or green, with different motion direction distributions. Results showed that statistical information can transfer from one group of stimuli to another but observers are also able to learn two distinct priors under specific conditions. In a collaborative work, I implemented an online learning computational model, which showed that subjects’ behaviour was not in disagreement with a near-optimal Bayesian observer, and suggested that observers might prefer simple models which are consistent with the data over complex models. Next, I investigated experimentally whether selective manipulation of rewards can affect an observer’s perceptual performance in a similar manner to manipulating the statistical properties of stimuli. Results showed that manipulation of the reward scheme had similar effects on perception as statistical manipulations in trials where a stimulus was presented but not in the absence of stimulus. Finally, I used a novel visual search task to investigate how expectations of different timescales (from the last few trials to hours to long-term statistics of natural scenes) interact to alter perception. Results suggested that recent exposure to a stimulus resulted in significantly improved detection performance and significantly more visual ‘hallucinations’ but only at positions at which it was more probable that a stimulus would be presented. These studies provide new insights into the approximations that neural systems must make to implement Bayesian inference. Complexity does not seem to necessarily be a prohibitive factor in learning but the system also factors the provided evidence and potential gain in regards to learning complex priors and applying them in distinct contexts. Further, what aspects of the statistics of the stimuli are learned and used, and how selective attention modulates learning can crucially depend on specific task properties such as the timeframe of exposure, complexity, or the observer’s current goals and beliefs about the task.

<p> Experiments have shown that manipulations of vocal fundamental frequency, a physical correlate of voice pitch, alter perceptions of vocal attractiveness. Individual experiments, however, have found different effects of pitch manipulations on attractiveness. One possible explanation for the disparate findings may be differences in the strength of pitch manipulations used between studies. The focus of this thesis is to determine psychophysical properties of vocal attractiveness based on pitch manipulations. Within the thesis, two experiments are described that were designed to find just-noticeable differences in vocal attractiveness based on pitch manipulations. The experiments were also designed to determine if there are limits for voice pitch preferences. Relevant background concepts to the thesis are described in Chapters 2-5, and a manuscript is presented in Chapter 6 that describes the methods and results of the experiment, and gives a discussion of the findings.</p> <p> In Chapter 2, the basic anatomy underlying vocal production is explained, including the anatomical structures involved in the source-filter model of vocal production.</p> <p> In Chapter 3, relevant acoustic properties of the voice are described, including fundamental frequency, harmonics, and formant frequencies.</p> <p> In Chapter 4, the basic anatomy involved in audition is explained, including how sound is propagated through the ear.</p> <p> In Chapter 5, a brief review of previous psychophysical research on pitch discrimination and perceived vocal traits is given.</p> <p> In Chapter 6, two experiments are described. Experiment 1 was designed to determine just-noticeable differences in voice pitch discrimination. Experiment 2 was designed to determine just-noticeable differences in voice attractiveness based on manipulations of voice pitch. Experiment 2 was also designed to assess potential limits to voice pitch preferences for supernormal stimuli. Just-noticeable differences in vocal attractiveness were larger than just-noticeable differences in pitch discrimination. Just-noticeable differences in attractiveness were larger in women's voices than men's. There was no limit in men's preferences for highpitched voices, however there was a limit for women's preferences for low-pitched voices below the natural male pitch range.</p> / Thesis / Master of Science (MSc)

<p> The study contains two discriminatory tasks which are attempted separately and simultaneoulsly. The subject is asked to judge the relative positions of successively presented points of light and/or to decide whether a test tone is added to continuous white noise during the interval between the two lights. It is noted that this design is similar to a retroactive interference paradigm. Analysis of the data shows that there is little interaction between decisions to each of the psychophysical tasks when they are attempted simultaneously. There also appears to be no significant change in sensitivity whether the tasks are attempted alone or together. It is suggested that-further experiments, involving different forms of visual memory, are needed.</p> / Thesis / Master of Arts (MA)

This thesis explores the ways in which an actor training scheme can be constructed to allow the participants to directly apply the principles of training to their work in the moment of performing. Subsequently, my aim is to employ this actor training approach alongside or as an alternative to the current acting courses in undergraduate drama programmes in Thai universities. Three practical projects were carried out as part of the research. In the first project, I attempted to identify essential areas of enquiry in a psychophysical actor training approach, and the tasks that needed to be tackled by an actor in rehearsal and performance that allow what may be considered the quality of an actor’s presence to emerge. In the second practical project, I examined the function of meditation in motion as an actor training tool that enables the participants to tackle their performance tasks. In the third practical project, I explored the ways in which meditation in motion can be employed in a university actor training course in Thailand to enhance the students’ mindfulness in performance. This thesis argues that Buddhist concepts of meditation and mindfulness are beneficial to the course facilitator in terms of the structuring of an actor training course, and to the students when approaching performance tasks. The main result of this research is a psychophysical approach to actor training, focusing on the practice of meditation in motion and the Buddhist concept of mindfulness of the present, designed specifically for Thai undergraduate drama programmes. Moreover, this thesis demonstrates a move away from the East-West binary towards a more localised and customised approach to actor training in Thailand and the utilisation of resources within the Thai or the broader Asian culture. It also opens up other possibilities of applying Thai or Asian philosophies to performance training, without relying on the Western perspectives on theatre and performance.

A proposta deste estudo foi determinar se as escalas visual analógica (VAS) e CR10 (Category-Ratio) de Borg são eficientes para avaliar o esforço geral percebido em um teste de exercício físico dinâmico contínuo. A amostra foi composta por 20 participantes do sexo masculino, com idade entre 18 e 29 anos, universitários, saudáveis, sedentários e que apresentavam valores ergoespirométricos compatíveis com a normalidade (Consenso Brasileiro de Ergometria). Os participantes realizaram o protocolo do teste de exercício físico dinâmico contínuo do tipo rampa (TEFDC-R) em um cicloergômetro eletromagnético à 60 rpm, juntamente com a aplicação das escalas psicofísicas escolhidas. A freqüência do esforço na presença do exercício foi induzida através do aumento da complexidade e da resistência, com a utilização do teste já mencionado. Para a análise dos dados foi utilizada análise psicofísica e estatística paramétrica por meio da correlação de Pearson, regressão linear e teste t de Student. Foram encontradas correlações estatisticamente significativas (p<0,05) entre as escalas (r=0,97), as escalas em função do consumo de oxigênio (CR10: r=0,90; VAS: r=0,90) e em função da freqüência cardíaca (CR10: r=0,89; VAS: r=0,91). Foram encontrados também julgamentos precisos independente da escala utilizada (n=0,99; r2=0,998). Estes resultados sugerem que as magnitudes físicas das escalas VAS e CR10 de Borg são altamente correlacionadas. Além disso, em ambas as escalas, o aumento da potência, da freqüência cardíaca e do consumo de oxigênio corresponderam ao aumento das estimativas subjetivas dos participantes em relação ao esforço físico. Isto pode indicar uma boa interação entre as diferentes variáveis atuantes durante o exercício físico dinâmico contínuo. / The purpose of this study was to determine if the visual analogue and Borg´s CR10 (Category-Ratio) scales are efficient for assessment of the perceived general exertion in a continuous dynamic physical exercise test. The sample was composed of 20 healthy male university students, with ages ranging from 18 to 29, sedentary and presenting compatible spirometric values with normality (Brazilian Consensus on Ergometry). The subjects filled out the protocol of the ramp continuous dynamic physical exercise test (RCDPET) using an electrically braked cycle ergometer at a pace of 60 rpm, with the application of the psychophysical scales. The frequency of the effort during the exercise was induced through the increase of the complexity and the resistance, using the test already mentioned. For the data analysis psychophysics analysis and parametric statistics were used, through the Pearson correlation, linear regression and Student-t test. A clear linear correlation was found between the scales (r=0,97, p<0,05), the scales and oxygen uptake (CR10: r=0,90; VAS: r=0,90) and heart rate values (CR10: r=0,89; VAS: r=0,91). Precise assessment were also found irrespective from the scale used (n=0,99; r2=0,99). These results suggest that the physical magnitudes of VAS and Borg´s CR10 scales are highly correlated. Moreover, in both scales, the increase of the power, the heart rate and the oxygen uptaken corresponds to the increase of the subjective estimations of the participants in relation to the physical effort. These may indicate a clear interaction between the different variable present during the continuous dynamic physical exercise test.