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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studying the brain mechanisms of dyspnoea with functional magnetic resonance imaging

Hayen, Anja January 2014 (has links)
Dyspnoea (breathlessness) is a debilitating, often poorly controlled, symptom of cardiopulmonary, neurovascular and psychological disorders. This thesis develops the necessary methodology to dissociate aspects of the acute dyspnoea experience using functional magnetic resonance imaging (FMRI) in healthy volunteers. The neuronal mechanisms underlying dyspnoea anticipation, its perceived intensity and unpleasantness and the modulation of these mechanisms by the opioid remifentanil were explored. We investigated the subjective perception of respiratory loading, a commonly used dyspnoea stimulus, and its potential systematic confounds on FMRI due to cerebral blood flow changes. Investigation of the perception of respiratory loading at different levels of hypercapnia (increased end-tidal CO<sub>2</sub>) showed that hypercapnia should be kept to a minimum to avoid increased baseline respiratory unpleasantness whilst maintaining the stable arterial CO<sub>2</sub> (isocapnia) beneficial for FMRI analysis. Investigation of the effects of respiratory loading (± 9 cmH<sub>2</sub>O) on cerebral blood flow showed that systematic confounds of respiratory loading on perfusion-based neuroimaging data were small (~5%) and did not significantly alter neural activation in response to visual stimulation. Isocapnic respiratory loading during a classical fear-conditioning paradigm during FMRI was used to investigate dyspnoea anticipation, and dissociate the intensity and unpleasantness of acute dyspnoea by modulating unpleasantness with remifentanil. Differential neural networks were found to be involved in perceived intensity (thalamus, insula, somatosensory cortex) and unpleasantness (hippocampus, medial prefrontal cortex). Remifentanil reduced respiratory unpleasantness without affecting the perceived intensity and differentially reduced brain activity during both dyspnoea anticipation and perception. This thesis showed the potential of isocapnic respiratory loading for the study of dyspnoea with FMRI. This stimulus revealed, for the first time, brain activation for dyspnoea anticipation, perceived intensity and unpleasantness. The opioid-sensitive nature of the anticipation and unpleasantness of dyspnoea provides brain targets for future research and might facilitate more effective dyspnoea palliation.
2

Broad spatial pooling with local detectors for grating detection revealed with classification image analysis /

Morgenstern, Yaniv. January 2006 (has links)
Thesis (M.A.)--York University, 2006. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 89-93). 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:MR19699
3

Confidence based calibration and the detection of early cognitive loss in probable and possible Alzheimer's disease sufferers /

Minns, Joanne E. January 1900 (has links)
Thesis (M.A.) - Carleton University, 2002. / Includes bibliographical references (p. 56-64). Also available in electronic format on the Internet.
4

Human S-cone electroretinograms obtained by silent substitution stimulation

Maguire, John, Parry, Neil R.A., Kremers, Jan, Murray, I.J., McKeefry, Declan J. 27 December 2017 (has links)
Yes / We used triple silent substitution stimuli to characterize human S-cone electroretinograms (ERGs) in normal trichromats. Short-wavelength-cone (S-cone) ERGs were found to have different morphological features and temporal frequency response characteristics compared to ERGs derived from L-cones, M-cones, and rod photoreceptors in normal participants. Furthermore, in two cases of retinal pathology, blue cone monochromatism (BCM) and enhanced S-cone syndrome (ESCS), S-cone ERGs elicited by our stimuli were preserved and enhanced, respectively. The results from both normal and pathological retinae demonstrate that triple silent substitution stimuli can be used to generate ERGs that provide an assay of human S-cone function. / Deutsche Forschungsgemeinschaft (DFG) (KR1317/13-1); Bundesministerium für Bildung und Forschung (BMBF) (01DN14009)
5

Synaesthesia : an essay in philosophical psychology /

Gray, Richard Unknown Date (has links)
Thesis (Ph.D.)--University of Edinburgh, 2001.
6

A quantitative examination of ostensibly extrasensory experiences occurring spontaneously and in laboratory conditions

Roberts, B. L. H. January 2013 (has links)
Parapsychological research, including the examination of the anomalous process termed ‘psi’, is highly controversial, with the existence of psi not accepted by mainstream science. The aim of this thesis was to study one aspect of psi, extrasensory perception (ESP), to examine whether evidence for ESP could be obtained or whether ostensibly extrasensory experiences can be attributed to purely psychological processes. Three studies are reported. The first obtained reports of spontaneous cases of ostensible ESP from 94 participants, using an online survey. Participants described their experience and responded to a series of questions regarding the aftermath of their experience and their reasoning for a paranormal interpretation. Results demonstrated several patterns that replicated earlier findings, including the predominance of female percipients, serious events, and close relationships between the percipient and target person. Negative emotions were common, including shock and confusion, particularly at the point of ostensible confirmation of the experience; the most common long-term response was an increase in paranormal belief, although some participants were relatively unaffected. Approximately two-thirds of participants had considered viable normal explanations for their experience, including coincidence and expectation of likely outcomes. Paranormal explanations were commonly attributed to the lack of a viable normal explanation, the striking coincidence between the experience and event, or the unusual nature of the experience. Many cases were weak evidentially; findings overall suggest that many ostensibly extrasensory experiences may have non-psi explanations. Two subsequent studies examined ESP in laboratory conditions, using the ganzfeld paradigm. Based on findings from spontaneous case research and previous laboratory studies, it was examined whether success was related to the emotional bond between pairs of participants, or to their sexes. The first study employed 30 pairs of participants, each taking part once as sender and once as receiver. Picture postcards were used as targets, and an emotional connectedness scale was used to assess pairing closeness. Direct hits and binary hits were above mean chance expectation (MCE); both were non-significant, although binary hitting was only marginally so. Results were suggestive of improved performance for closer pairings and mixed-sex pairings, but were non-significant. The second study was a partial replication, with 40 pairs of participants and using video clips as targets. EEG recordings were taken from the frontal midline (Fz) site of both participants. Approximately half of senders experienced stroboscopic stimulation at 6Hz throughout the trial in an attempt to drive theta rhythms associated with a hypnagogic state, mirroring the state expected in receivers due to ganzfeld stimulation. Direct hits were at MCE, while binary hits were non-significantly above MCE; binary hitting across the two studies was significant. There was no effect of pairing closeness or sexes on success, and hitting was not associated with any EEG features or with strobe usage. Overall, laboratory findings appeared promising in terms of significant binary hitting but continued a trend of inconsistency within and between ganzfeld ESP studies. This inconsistency, together with the many weakly evidential spontaneous cases collected, point more strongly to a psychological interpretation of ostensibly extrasensory experiences, rather than the elusive psi.
7

Investigating the subcomponents of working memory in multi-digit arithmetic problems /

Coleman, Benjamin, January 1900 (has links)
Thesis (Ph. D.)--Carleton University, 2004. / Includes bibliographical references (p. 119-130). Also available in electronic format on the Internet.
8

Effects of phonological, visual and spatial information processing on a simulated driving task /

Trbovich, Patricia L., January 1900 (has links)
Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 138-153). Also available in electronic format on the Internet.
9

Zrakové vnímání řidiče v dopravním provozu / Eye Perception of Drivers in Traffic

Vorálková, Kateřina January 2012 (has links)
The aim of thesis is a summary and assessment of perception of drivers in traffic from the view of psychology and its influence on various aspects and the resulting effects on driving. Furthermore, it is mainly a description of the visual system and the description of light as factor of visual perception. The thesis also presents two experiments refer to the reaction time and mental reactions of driver, depending on drank out alcohol. Results of the first test of reaction time starting at the traffic lights were just a confirmation of the mentioned values from different publications and the Internet. The results of the second test, which was focused on the emotional reaction depending on the amount of ingested alcohol would be surprising to many.
10

Struktura hudby a časová percepce / Music Structure and Time Perception

Becková, Adéla January 2021 (has links)
The diploma thesis follows the bachelor's thesis Music and Time Perception (Becková, 2017). It focuses on time perception in music. It reviews current influential theories and models in the research of time perception, and also time perception models in relation to music, ie models based on the existence of internal time clocks and models based on attentional, memory and other dynamic processes. It also focuses on the psychological aspects of the metrum, rhythm and other musical characteristics in relation to time perception. Possible use of research findings in the field of time perception in music is also mentioned. In the experimental part I applied specific findings from the current research of time perception to short acoustic stimuli in the range of suprasecond intervals using reproduction as experimental paradigma. The filled- duration illusion, the divided time illusion and an effect of tone pitch were demonstrated. The findings from the experiment could be used in future research in the field of music and time perception. Klíčová slova: time perception, music perception, psychology of time

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