• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 38
  • 5
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 48
  • 48
  • 24
  • 23
  • 12
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • 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.
11

Psychobiological correlates of distress in pregnancy

Roos, Annerine 03 1900 (has links)
Thesis (PhD (Psychiatry))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Pregnancy is often accompanied by distressing psychological symptoms such as anxiety. These symptoms may result from changes in cognitive-affective processing, which in turn reflect hormonal changes during this time. However, findings on associations between psychological distress, cognitive-affective changes and hormones have been inconsistent. Furthermore, few studies have investigated the neural circuitry underlying distress and cognitive-affective processing in pregnancy. The prefrontal cortex (PFC) plays a specific role in regulating emotion. Determining the relationship between these changes in cognitive-affective processing and in prefrontal circuitry is important, given the high prevalence of depressive and anxiety disorders in pregnancy. The overall objective of this study was to investigate distressing psychological symptoms and their association with cognitive-affective processes and neurobiological changes over the course of pregnancy. Pregnant women with low risk singleton pregnancies were recruited from Midwife Obstetric Units in the Western Cape. Non-pregnant healthy controls were also recruited from the same demographic area. Distress levels were assessed using the K-10, Spielberger State -Trait Inventory, and Perceived Stress Scale. Subjectively experienced cognitive ability was asked about. Objective cognitive ability was assessed using standardized neuropsychological tests. Selective attention to threat such as fear and anger was assessed using a Facial Stroop Task. Neural circuitry was assessed using Near-Infrared Spectroscopy while viewing dynamic emotional facial expressions of threat (Emotion Recognition Task). Glucocorticoid (cortisol) and gonadal hormonal levels (estrogen, progesterone, and testosterone) were also determined at each trimester of pregnancy. Associations between distressing psychological symptoms, cognitive-affective processes and neurobiology were assessed using standard statistical methods. The main findings to emerge from this research were that, 1. pregnant women had significantly higher trait anxiety at trimester 2, compared to trimester 1 of pregnancy; 2. compared to non-pregnant women, pregnant women paid significantly more attention to fearful faces across trimesters, suggesting altered cognitive-affective processing in pregnancy compared to non-pregnancy; 3. pregnant women demonstrated significantly increased PFC activation in response to fearful and angry faces (all trimesters) that was particularly evident at trimester 2; 4. the PFC activation was, across trimesters, significantly correlated with distress and selective attention to threat; and 5. the PFC activation was, across trimesters, also significantly associated with increased glucocorticoid and gonadal hormone levels. The main findings of this study are consistent with previous literature insofar as distress has previously been associated with altered cognitive-affective processing and prefrontal cortex activation, but extend it by showing that emotional regulation is altered in pregnancy compared to the non-pregnant state. These data provide an important insight into distressing psychological symptoms and their associations with cognitive-affective processes, and changes in neural circuitry and in hormone levels in pregnancy. These findings are also the first to show that structures involved in emotional processing (e.g. the PFC) also play a role in the regulation of affect in pregnancy. Future research should explore the causal mechanisms underlying altered emotional regulation in pregnancy, and include pregnant women that are clinically depressed or anxious as comparison subjects. / AFRIKAANSE OPSOMMING: Swangerskap word dikwels geassosieër met stres-veroorsakende sielkundige simptome soos angstigheid. Hierdie simptome mag die gevolg wees van veranderinge in kognitief-affektiewe prosessering, wat op sy beurt mag dui op hormonale veranderinge. Bevindinge oor assosiasies tussen sielkundige stres, kognitief-affektiewe prosessering en hormone is tot dusver onbeslis. Voorts was min studies gerig op die neurologiese meganika onderliggend aan stres en kognitief-affektiewe prosessering tydens swangerskap. Die prefrontale korteks (PFK) het 'n spesifieke rol in die regulering van emosie. Die bepaling van spesifieke assosiasies tussen veranderinge in kognitief-affektiewe prosessering en in prefrontale regulering is belangrik, gegewe die hoë voorkoms van toestande soos depressie en angssteurings tydens swangerskap. Die doel met hierdie studie was 'n ondersoek na assosiasies tussen stres-veroorsakende sielkundige simptome, kognitief-affektiewe prosesse en neurobiologie tydens swangerskap. Swanger vroue met lae risiko enkel-swangerskappe is gewerf by klinieke in Wes-Kaapland. Gesonde nie-swanger vroue is uit dieselfde omgewing gewerf as kontroles. Angs-vlakke is geevalueer met behulp van die K-10; die Spielberger State-Trait Inventory en die Perceived Stress Scale. Vrae is tydens ondersoeke gevra oor subjektief-ervaarde kognitiewe vermoë. Voorts is kognitiewe vermoë geëvalueer met behulp van gestandardiseerde neurosielkundige toetse. Hierbenewens is selektiewe aandag aan bedreigende gesigte wat vrees en woede toon, geëvalueer met behulp van 'n Facial Stroop Task. Neurologiese funksie is geëvalueer met gebruik van Na-Infrarooi Spektroskopie terwyl dinamiese bedreigende emosionele gesigsuitdrukkings vertoon is (Emotion Recognition Task). Gluko-kortikoïed (kortisol) en geslagshormoonvlakke (estrogeen, progesteroon, en testosteroon) is gemeet tydens elke trimester. Verwantskappe tussen stresvolle simptome, kognitief-affektiewe prosessering en neurobiologie is geëvalueer met standaard statistiese metodes. Die hoofbevindinge het op die volgende gedui: 1. swanger vroue het betekenisvolle hoër trait angs-vlakke getoon in trimester 2, vergeleke met trimester 1; 2. vergeleke met nie-swanger vroue, het swanger vroue beduidend meer aandag geskenk aan angstige gesigsuitdrukkings tydens elke trimester wat mag dui op veranderde kognitief-affektiewe prosessering tydens swangerskap vergeleke met nie-swangerskap; 3. swanger vroue het beduidend hoër PFK aktivering getoon teenoor angstige en kwaai gesigte in alle trimesters, maar veral in trimester 2; 4. swanger vroue se PFK aktivering het, in alle trimesters, beduidend gekorreleer het met stres-vlakke en selektiewe aandag teenoor bedreigende stimuli; en 5. swanger vroue se PFK aktivering het, in alle trimesters, ook 'n beduidende verwantskap getoon met verhoogde gluko-kortikoïed en geslagshormoonvlakke. Die hoofbevindinge in hierdie studie stem ooreen met vorige literatuur wat aangedui het dat daar 'n verband is tussen stres en veranderinge in kognitief-affektiewe prosessering en in prefrontale korteks aktivering, maar dui verder op veranderinge in emosionele regulering tydens swangerskap vergeleke met nie-swangerskap. Die data bied 'n belangrike insig in stres-veroorsakende sielkundige simptome; hul verwantskap met kognitief-affektiewe prosesse; veranderinge in neurologiese netwerke; en veranderinge in hormoonvlakke tydens swangerskap. Sover bekend is dit ook die eerste keer bevind dat strukture wat betrokke is by emosionele prosessering (bv. die PFK), ook betrokke is in die regulering van emosie tydens swangerskap. Dit is belangrik dat toekomstige navorsing die onderliggende meganismes wat veranderinge in emosionele regulering teweeg bring, ondersoek. Verdere ondersoek om hierdie veranderinge in swanger depressie-lyers of diegene met angssteurings te vergelyk is ook van belang.
12

The Effect of Mindfulness Meditation on Affect and Attention : An Empirical Study

Bryde, Jonathan January 2019 (has links)
In daily life there are numerous experiences and events that divert people's attention and cause stress, which may be linked with aspects of ill-being and lowered well-being. Mindfulness meditation may alleviate such issues. Mindfulness can be summarized as a form of awareness and attention in the present that is characterized by an open-minded and non-judgemental perspective, and meditation as a group of practices that engage many of the same processes and may involve mindfulness. There is evidence that both mindfulness and mindfulness meditation are associated with activity in brain regions relating to, for example, attention, emotion-regulation, and bodily awareness. Consequently, mindfulness meditation was hypothesized in the present study to improve attention as measured by the Attention Network Test, and decrease negative affect as measured by the Positive and Negative Affect Schedule when compared to a control condition. The mindfulness meditation instructions employed were largely based on the work of Kabat-Zinn (1982). 14 participants were recruited to the study, and 7 of them completed the experiment. 3 participants were randomized to the experimental group, and 4 to the control group. Results were largely contrary to the hypotheses, with only executive attention having statistical significance (p < .05) and supporting one hypothesis. Although effect sizes were on average large for the variables of the study, the small sample size may have limited the power and increased the risk for type-II errors.
13

Merging the Philosophical and Scientific Studies of Consciousness

Kozuch, Benjamin January 2013 (has links)
The philosophical and scientific studies of consciousness are two disciplines having much to learn from one another. On the one hand, a science of consciousness involves taking an objective approach to what is essentially a subjective phenomenon, giving rise to tricky conceptual and methodological issues, ones an analytic philosopher is perhaps best equipped to handle. On the other hand, a wealth of data now exists concerning the neural basis of consciousness. Such data, interpreted properly, can confirm or disconfirm philosophical views on consciousness, helping adjudicate debates thus far intractable. This dissertation explores some ways in which the philosophy and science of consciousness can be of mutual benefit to one another.
14

Neural Correlates of Heart Rate Variability : Threat and Safety Perception

Frändén, Philip January 2018 (has links)
The connection between the heart and the brain was coined 150 years ago by Claude Bernard and has since then been an interesting topic of research. Scientists have for many years searched for biomarkers of stress and health to map the current status of the organism. Heart rate variability (HRV) has been presented as an emerging objective and promising marker to achieve just this. HRV refers to the beat-to-beat variations in heart rate (HR) and is thought to be a useful signal in understanding and providing valuable information of the autonomic nervous system (ANS). HRV has also been proposed as a marker of stress and health by sharing neural correlates and functions with several executive functions. This thesis identified several regions, including the ventromedial prefrontal cortex and the amygdala, in which significant associations across several studies were found between threat and safety perception, emotional regulation and HRV. This suggest that HRV may function as an index of the brain mechanism and structures that guide and govern adaptive functions and thus, provide researchers with valuable information regarding the stress and health of an organism. Two major theoretical frameworks, which articulate and explain the role of HRV as an indicator of individuals ability to adapt to environmental changes and cope under stress is presented. HRV can also be used in practice in several ways and a growing and promising field of application is HRV biofeedback.
15

Neural correlates of lucid dreaming and comparisons with phenomenological aspects

Lindberg, Markus January 2014 (has links)
Research on the neural correlates of lucid dreaming has recently gained more underlying data. By exploring seven studies that investigated the neural basis of lucid dreaming, this essay sought to examine which neural correlates are associated with lucid dreaming and how proposed neural correlates relate to phenomenological aspects. Dorsolateral prefrontal cortex (DLPFC) was judged as the region most associated with lucid dreaming, in support of a DLPFC hypothesis. Support for reactivation of DLPFC in lucid dreaming consisted of data from electroencephalography, functional magnetic resonance imaging, and transcranial direct current stimulation. Phenomenological aspects associated with this region involved meta-awareness, working-memory, decision-making, and conscious perception. Other regions of interest were parietal areas, frontal areas, and precuneus. Data was not always compatible, implying need for further research. The possibility of further research was judged as promising, based on a recent study inducing lucid dreaming in a significant percent of its test subjects.
16

A cognitive neuroscience perspective of emotions

Lymperopoulou, Ioana Anca January 2015 (has links)
Emotions have a remarkable capacity to mobilize an individual and shape a person’s behavior in order to ultimately lead to a higher wellbeing. The importance of emotions is further emphasized by pathological cases of people who suffer from an inability to normally regulate their emotional life, such as people who suffer from major depression disorder (MDD), eating disorders, or borderline personality disorder. Given the central role emotions play in our lives, it is very easy to understand the great interest cognitive neuroscientists have in this research field. Emotions have been approached in the last decades from different angles and as such, distinct theories arose. The goal of this study is to give a comprehensive overview of the emotion theories that exist, with a focus on three of the fastest developing cognitive theories of emotions: Frijda’s action-readiness, Russell’s core affect and the communicative theory. Additionally, the neural correlates of emotions will be discussed, focusing on the role of amygdala in the negative emotion of fear. Neuroimaging studies that reveal a correlation between the amygdala and emotions, fear in particular, will be described. Given that the ability of self-regulation is crucial for the achievements of our aims and goals, fMRI studies designed to investigate neural the underpinnings of emotion regulation will be presented. The process of cognitive reappraisal will be used to point towards the brain regions that act as down-regulators for the activity of amygdala while processing negatively valenced stimuli.
17

Well-being and Dispositional Optimism in Uganda and Sweden : An empirical and neurobiological investigation

Lönn, Josefina January 2015 (has links)
Uganda´s well-being ranks among the worst in the world, while Sweden´s well-being ranks among the best. This thesis investigates if there is a difference in well-being and dispositional optimism in Uganda and Sweden. The neurobiology underlying well-being and optimism is also examined. The neural correlations of well-being and optimism are connected to areas in the limbic system and cerebral cortex. Prefrontal cortex and anterior cingulate cortex are two curial regions involved in both well-being and optimism. Amygdala, parahippocampal gyrus, and thalamus are central areas for hedonic well-being, dispositional optimism, and optimism bias. In this thesis 284 Ugandans and 256 Swedes completed a questionnaire based survey. Greater hedonic well-being was found among Swedes, whereas greater eudiamonic well-being was found among Ugandans. Swedes reported greater global life satisfaction than Ugandans, but Ugandans expressed higher satisfaction with their current lives compared with Swedes. In relation to dispositional optimism, Ugandans were found to be both more optimistic and more pessimistic than Swedes. This unexpected dispositional optimism pattern is discussed and future research directions are proposed.
18

Moral machines : The neural correlates of moral judgment and its importance for the implementation of artificial moral agency

Winnerheim, Kristin January 2020 (has links)
Society and technology are advancing, in which morality is being artificially implemented into machines, often known as artificial moral agency. Along with this implementation, knowledge about the underpinnings of morality, such as the neurocognitive and ethical basis are an important matter. Human moral judgment has been speculated to be a function for survival, as it favors altruism and prosocial behavior. The neural correlates of moral judgment stem from several structures of the human brain that control cognitive and affective functions such as decision making, cognitive control, theory of mind (ToM) and empathy. In relation to these, the ventromedial prefrontal cortex (vmPFC) has been widely linked to moral behavior such as ToM and moral judgment. The anterior cingulate cortex (ACC) has been linked to regulation of conflict and the dorsolateral prefrontal cortex (dlPFC) to remain cognitive control, which both have strong correlations to moral behavior. Damage to areas such as the vmPFC and ACC have demonstrated abnormal response to guilt, ToM, empathy, risky behavior as well as sociopathic tendencies, which emphasizes the importance of these structures for human morality. By investigating research in the fields of cognitive neuroscience, moral psychology and machine ethics, this thesis aims at seeking out the importance of cognitive neuroscience for the development of artificial moral agency and to furthermore discuss the necessity of emotions in artificial moral agents, which naturally lack the affective part of moral judgment. Lastly, this thesis will cover some of the main dilemmas with this integration and some future implications.
19

EMPATHIC DISTRESS : The Dark Side of Caring?

Engelbrektsson, Hilda January 2020 (has links)
The current review aims to unravel what is known regarding the neural substrates of empathicdistress and compassion fatigue. Empathic distress is a self-oriented feeling of anxietyexperienced in response to the suffering of another. It has been related to, and theorized to bea precursor of, compassion fatigue. This is a form of caregiver burnout received by secondaryexposure to trauma. In the current thesis, Scopus, Web of Science and PsycINFO weresearched identifying 301 articles that were subsequently screened. In the end, five studieswere included that measured either empathic distress or compassion fatigue in relation tobrain structure or function. Findings are largely inconsistent but areas involved in theory ofmind and that are important for the self-other distinction are discussed. A need for moreresearch is identified, together with a desire for conceptual clarification between compassionfatigue and burnout.
20

Parietal thalamocortical circuitry in global dream cessation

Hattingh, Coenraad J 25 February 2020 (has links)
Until relatively recently, the overarching agreement in the clinical literature was that total cessation of dreaming is related to posterior parietal lesions. Two recent case reports (Bischof and Bassetti, 2004; Poza and Martí-Massó, 2006), in which patients with medial occipital lesions demonstrated total cessation of dreaming, cast doubt on this clinic-anatomical correlation, and the neuropsychological theory of dreaming associated with it (Solms, 1997). In the current study, seven patients with medial occipital lesions (with posterior cerebral artery ischemic lesions) were recruited. Three patients had total dream cessation and four had intact dreaming (confirmed on REM awakening). Acute phase clinical neuroimaging was reviewed and the extent of the lesions in both groups was meticulously analysed by a neuroanatomist, who was blind to the dreaming status of each patient. The three patients with total cessation of dreaming all demonstrated posterior thalamic infarctions involving the pulvinar nucleus. All four of the patients with intact dreaming demonstrated medial temporo-occipital lesions, and none had thalamic lesions. Upon review of the source images of one of the two case studies with medial occipital damage and total dream cessation (Bischof and Bassetti, 2004), it was noted that the patient also demonstrated infarction of the pulvinar of the thalamus. The pulvinar of the thalamus has discrete thalamo-cortical connections to the parietal lobe, which it innervates. Disruption in the pulvinar of the thalamus can, therefore, reasonably be expected to result in parietal dysfunction. This study represents the largest case-report comparison in patients with REM-confirmed dream cessation with suitably circumscribed pathology. These findings cast doubt on claims of medial occipital mechanisms of dream cessation and suggest that posterior parietal circuitry remains involved.

Page generated in 0.0732 seconds