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The hippocampal dependence of long-term declarative memoryAlvarez Svahn, Rodrigo January 2015 (has links)
Investigations into the neural correlates of memory have found the hippocampus to be a crucial structure for long-term declarative memories, but the exact nature of this contribution remains under debate. This paper covers three theories concerned with how the hippocampus is involved in long-term memory, namely the Standard Consolidation Model, the Multiple-Trace Theory, and the Distributed Reinstatement Theory. According to the Standard Consolidation Model, long-term declarative memories (both episodic and semantic) are dependent on the hippocampus for a limited time during which the memories undergo a process of consolidation, after which they become dependent on the neocortex. In contrast, the Multiple-Trace Theory argues that detailed and context-specific episodic (but not semantic) memories remain dependent on the hippocampus indefinitely. While both the aforementioned theories posit that memories are initially dependent on the hippocampus, the Distributed Reinstatement Theory does not. Advocates of this theory propose that several memory systems compete for the encoding of a memory, and that the hippocampus usually is the dominant system. However, it is also suggested that the other (unspecified) memory systems can overcome the hippocampal dominance through extensive and distributed learning sessions. In this paper, findings from both human and rodent studies focusing on the hippocampus are reviewed and used to evaluate the claims made by each theory on a systems level.
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An evaluation of the Integrated Information Theory against some central problems of consciousnessOlsson, H. A. Joakim January 2015 (has links)
This thesis evaluates the integrated information theory (IIT) by looking at how it may answer some central problems of consciousness that the author thinks any theory of consciousness should be able to explain. The problems concerned are the mind-body problem, the hard problem, the explanatory gap, the binding problem, and the problem of objectively detecting consciousness. The IIT is a computational theory of consciousness thought to explain the rise of consciousness. First the mongrel term consciousness is defined to give a clear idea of what is meant by consciousness in this thesis; followed by a presentation of the IIT, its origin, main ideas, and some implications of the theory. Thereafter the problems of consciousness will be presented, and the explanation the IIT gives will be investigated. In the discussion, some not perviously—in the thesis—discussed issues regarding the theory will be lifted. The author finds the IIT to hold explanations to each of the problems discussed. Whether the explanations are satisfying is questionable.
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The Virtual Self : Sensory-Motor Plasticity of Virtual Body-OwnershipFasthén, Patrick January 2014 (has links)
The distinction between the sense of body-ownership and the sense of agency has attracted considerable empirical and theoretical interest lately. However, the respective contributions of multisensory and sensorimotor integration to these two varieties of body experience are still the subject of ongoing research. In this study, I examine the various methodological problems encountered in the empirical study of body-ownership and agency with the use of novel immersive virtual environment technology to investigate the interplay between sensory and motor information. More specifically, the focus is on testing the relative contributions and possible interactions of visual-tactile and visual-motor contingencies implemented under the same experimental protocol. The effect of this is supported by physiological measurements obtained from skin conductance responses and heart rate. The findings outline a relatively simple method for identifying the necessary and sufficient conditions for the experience of body-ownership and agency, as studied with immersive virtual environment technology.
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Neural correlates of lucid dreaming and comparisons with phenomenological aspectsLindberg, 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.
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Using the Brain to Help Rehabilitate the Body : Factors which can Affect Injury Rehabilitation OutcomeRydh, Mathias January 2014 (has links)
Physical activity can be beneficial to both physical and mental health, but can also lead to injuries. While injury rehabilitation through physical therapy is mostly focused on physical exercise, there are also other factors, which may influence rehabilitation outcome. The factorsreviewed are: rehabilitation adherence, mindfulness meditation, mental imagery, action observation, self-talk, goal-setting and social support. This essay investigates the neural correlates of these factors, as well as how they can affect rehabilitation outcome and wellbeing, to a lesser degree, during rehabilitation. Among the effects found are performance enhancement, increased self-efficacy, increased pain tolerance, increased motivation and reduced strength loss. Suggestions for future research is also provided.
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Neural Mechanisms Underlying Self-Localization in RodentsThelander, Jenny January 2015 (has links)
The ability to self-localize and navigate in both stable and changing environments is crucial for the survival of many species. Research conducted on the non-human mammalian hippocampus and surrounding brain structures has uncovered several classes of spatial related cells. These cells provide the rest of the brain with knowledge of the animal’s location and direction—knowledge that is subsequently used in spatial navigation. This thesis provides an overview of three types of cells underlying this ability in rodents. First, place cells located in the hippocampus encode the animal’s specific location in the environment. Second, head direction cells found throughout the Papez circuit convey the angular direction of the animal’s head. Last, grid cells in the medial entorhinal cortex generate a regular triangular grid spanning the entire explored setting. The focus of this review lies on the most salient features of these types of cells. It is also considered how the cells respond to manipulations of external and internal information, as well as how different lesions affect their activity.
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A cognitive neuroscience perspective of emotionsLymperopoulou, 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.
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Cultural Differences in Optimism, Pessimism and Eudaimonic Well-Being from a Neurobiological PerspectivePlan, Alexsandra January 2015 (has links)
The present thesis provides a theoretical overview, including a neurobiological perspective, of well-being (WB), eudaimonic well-being (EWB), optimism, pessimism and cultural differences between Western and Eastern societies. In addition, an empirical study investigated these concepts in Japanese and Swedish participants. Definitional problems and scarce neurobiological findings are two current problems to date within research on WB, EWB and cultural differences especially when looking at comparisons between Europe and East Asia. Interpretations and conclusions are therefore hard and tentative to make as more research is yet needed. This thesis empirical part therefore investigated the association between these concepts. In the best of the authors knowledge have this type of explorative study never been done before. 142 Swedish participants and 68 Japanese participants between the ages of 20 to 40 answered the self-reporting questionnaires; revised life orientation test (LOT-R), psychological well-being scale (SPWB) and the minimalist well-being scale (MWBS). The findings demonstrate that Swedish people report higher levels of optimism compared with Japanese people whom in turn report higher levels of pessimism when measured with LOT-R. Findings further demonstrate that Swedish people report higher levels of EWB when measured with SPWB. In comparison do Japanese people report higher levels of EWB when measured with MWBS. A difference was found in response pattern between MWBS and SPWB. And last did the findings suggest correlations in total scores of MWBS, SPWB and LOT-R but not within all sub-dimensions. Discussion of the results, limitations of the thesis and suggestions for future research concludes the thesis.
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Measuring Emotions in Dreams: Methodological ChallengesFeilhauer, Diana January 2015 (has links)
Although emotions are a natural component of dream experiences, a lack of consensus prevails in research literature concerning the specific characteristics of emotional dream experiences. The aim of this study was to investigate if and to what extent this lack of convergence among studies stems from whether dream emotions are self- or externally rated - forty-four healthy participants (16 males and 28 females; mean age = 26.93, range = 19 - 40) kept a home dream diary for three consecutive weeks, and daily rated their emotional experiences in dreams with the Swedish modified Differential Emotions Scale (smDES; Fredrickson, 2013). Two external judges rated emotions in the same 552 home dream reports using the same scale. Results obtained with the two methods differed in that the self-ratings, compared to external ratings, revealed: (a) more emotional dreams; (b) more positive than negative emotions per dream (with the ratio being relatively balanced); (c) a relatively more balanced proportion of positive and negative emotions, while the external ratings revealed more negative than positive emotions per dream. The results suggest that this is mostly due to the underrepresentation of positive emotions with external ratings. Thus, the results continue to question the extent of convergence between self- and external ratings when investigating emotional dream contents, and bring to attention the importance of methodological aspects when investigating dream emotions.
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Idrottsprestationers påverkan av anspänning, oro och stress och förslag till prestationshöjande teknikerAsplund Fromholz, Marcus January 2014 (has links)
Anspänning, oro och stress är tre begrepp som har studerats länge, vilket har gett upphov till flertalet modeller, teorier och domäner där dessa begrepp har studerats och fortfarande studeras. I denna uppsats så kommer dessa tre begrepp bland annat att redogöras för var för sig med koppling till mätmetoder, idrott och kognitiv neurovetenskap. Syftet med uppsatsen är att beskriva hur idrottsprestationer kan påverkas av anspänning, oro och stress för att utifrån det kunna redogöra för evidensbaserade metoder som kan appliceras för att främja en idrottsprestation. Först kommer anspänning att redogöras för, anspänning följs sedan av oro som i sin tur följs av stress som sista begrepp. Avslutningsvis så behandlas även problematik och möjligheter för dessa begrepp inom forskningsfältet och dess tillämpningsområden.
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