Im Rahmen einer experimentellen Vergleichsstudie zweier bildwandlergestützter Navigationssysteme wurde die 3D-bildwandlergestützte Navigation mit der 2D-bildwandlergestützten Navigation zur Pedikelschraubenplatzierung am Modell getestet. Neben der Präzision der Bohrungen in einem postoperativen CT wurden Bildqualität, Genauigkeit des 3D-Scans, Planbarkeit und Umsetzung der Bohrungen bewertet und verglichen. Mit der 3D- Bildwandler- Navigation wurden 38 der 40 Bohrungen exakt platziert (95%). Eine Planung wurde durch einen Softwarefehler der Alpha-Version auf dem Monitor falsch wiedergegeben. Bei einer weiteren Bohrung wurde der Bohrer verkantet, wodurch Bildschirmdarstellung und Realität voneinander abwichen. Daher kam es in einem Fall zu einer lateralen Perforation der Kortikalis im Bereich des Pedikels, im anderen zu einer kaudalen Perforation. Mit der 2D- Bildwandler- Navigation konnten alle 40 Schrauben ohne Pedikelperforation platziert werden. Zwei dieser Schrauben wurden durch die ventrale Kortikalis gebohrt. Beide Verfahren überzeugten durch hohe Präzision und Zuverlässigkeit. 3 der 4 Fehlplatzierungen waren Anwender einer Software bedingt. Eine optimierte Software und verbesserte Instrumente werden diese Fehlerquote weiter reduzieren. Voraussetzung für die 2D-bildwandlergestützten Navigation sind eine gute Bildqualität sowie normale anatomische Gegebenheiten für standardisierte Projektionen. Die neue 3D-bildwandlergestützter Navigation kombiniert die Vorteile der 2D-bildwandlergestützter Navigation und der CT- basierten Navigation mit einer Verringerung der Strahlenbelastung durch den Wegfall des präoperativen CT`s und somit der Einsatzmöglichkeit im akuten Notfall sowie nach intraoperativen Repositionsmanövern. Da kein Matching erforderlich ist, wird insbesondere bei traumatischer Verletzung oder tumorbedingter Veränderung der dorsalen Wirbelstrukturen ein großer Vorteil zur CT- basierten Navigation erwartet. Aufgrund der universellen Einsatzmöglichkeiten eines Bildwandlers wird für diese neue Technologie ein breites Indikationsspektrum angenommen. / An experimental study to compare 2D- and 3D- Computer-Assisted Fluoroscopic Navigation for pedicle screw placement. Each system was evaluated by a post-operative CT and included the comparison of the palpation of the pedicular canal, the image quality and the accuracy of planning and performance. For this purpose 40 screws have been set to 9 models of lumbar spine. Using the 3D-flouroscopy based navigation 38 from 40 (95%) drillings were placed correctly. One mistake was caused by an error of the navigation-software. The second mistake was due to a drilling mistake, the drill was not shown correctly on the monitor because the drill has been canted. Using the 2D-flouroscopy based navigation all screws could be placed correctly at the pedicle, but two times the corpus has been perforated to ventral. Both techniques are precise and reliable. 3 out of 4 mistakes were caused by incorrect handling the instrument. The other mistake happened because of a software-error. If the software and the instruments will be optimised, the amount of mistakes will be reduced in the future. In case of the 2D-flouroscopy based navigation sufficient image quality, normal anatomical structures and defined projections are required. The new 3D-flouroscopy based navigation combines the benefit of 2D-flouroscopy based navigation and CT-based navigation by reducing the radiation exposure and the preoperative planning time. Therefore, this technique is suitable for use in an emergency or intraoperative repositions. Because no matching-procedure is necessary for CT-based navigation, we expect advantages especially in therapy of traumatic injuries or changes at the dorsal structures of spine caused by tumour. Furthermore, the use of fluoroscopic based navigation extends the range of applications/the spectrum of indication for this new technology.

A inferência do curso temporal da atividade neural a partir do efeito BOLD é um importante problema, ainda em aberto. A forma da curva BOLD não reflete diretamente as características temporais da atividade eletrofisiológica dos neurônios. Nessa tese, é introduzido o conceito de tempo de processamento neural (TPN) como um dos parâmetros do modelo biofísico da função de resposta hemodinâmica (HRF). O objetivo da introdução desse conceito é obter estimativas mais acuradas da duração da atividade neural a partir do efeito BOLD, que possui auto grau de nãolinearidade. Duas formas de estimar os parâmetros do modelo do efeito BOLD foram desenvolvidas. A validade e aplicabilidade do conceito de TPN e das rotinas de estimação foram avaliadas por simulações computacionais e análise de séries temporais experimentais. Os resultados das simulações e da aplicação foram comparados com medidas da forma da HRF. O experimento analisado consistiu em um paradigma de tomada de decisão na presença de distratores emocionais. Esperase que o TPN em áreas sensoriais primárias seja equivalente ao tempo de apresentação de estímulos. Por outro lado, o TPN em áreas relacionadas com a tomada de decisão deve ser menor que a duração dos estímulos. Além disso, o TPN deve depender da condição experimental em áreas relacionadas ao controle de distratores emocionais. Como predito, o valores estimados do TPN no giro fusiforme foram equivalentes à duração dos estímulos e o TPN no giro do cíngulo dorsal variou com a presença de distrator emocional. Observou-se ainda lateralidade do TPN no córtex pré-frontal dorsolateral. As medidas da forma da HRF obtidas por um método convencional não dectectaram as variações observadas no TPN / The extraction of information about neural activity dynamics related to the BOLD signal is a challenging task. The temporal evolution of the BOLD signal does not directly reflect the temporal characteristics of electrical activity of neurons. In this work, we introduce the concept of neural processing time (NPT) as a parameter of the biophysical model of the hemodynamic response function (HRF). Through this new concept we aim to infer more accurately the duration of neuronal response from the highly nonlinear BOLD effect. We describe two routines to estimate the parameters of the HRF model. The face validity and applicability of the concept of NPT and the estimation procedures are evaluated through simulations and analysis of experimental time series. The results of both simulation and application were compared with summary measures of HRF shape. We analysed an experiment based on a decision-making paradigm with simultaneous emotional distracters. We hypothesize that the NPT in primary sensory areas is approximately the stimulus presentation duration. On the other hand, the NPT in brain areas related to decisionmaking processes should be less than the stimulus duration. Moreover, in areas related to processing of an emotional distracter, the NPT should depend on the experimental condition. As predicted, the NPT in fusiform gyrus is close to the stimulus duration and the NPT in dorsal anterior cingulate gyrus depends on the presence of an emotional distracter. Interestingly, the estimated NPTs in the dorsolateral prefrontal cortex indicate functional laterality of this region. The analysis using standard measures of HRF did not detect the variations observed in our method (NPT)

En raison de l’utilisation d’un mode de communication totalement différent de celui des entendants, le langage des signes, et de l’absence quasi-totale d’afférences en provenance du système auditif, il y a de fortes chances que d’importantes modifications fonctionnelles et structurales s’effectuent dans le cerveau des individus sourds profonds. Les études antérieures suggèrent que cette réorganisation risque d’avoir des répercussions plus importantes sur les structures corticales situées le long de la voie visuelle dorsale qu’à l’intérieur de celles situées à l’intérieur de la voie ventrale. L’hypothèse proposée par Ungerleider et Mishkin (1982) quant à la présence de deux voies visuelles dans les régions occipitales, même si elle demeure largement acceptée dans la communauté scientifique, s’en trouve aussi relativement contestée. Une voie se projetant du cortex strié vers les régions pariétales postérieures, est impliquée dans la vision spatiale, et l’autre se projetant vers les régions du cortex temporal inférieur, est responsable de la reconnaissance de la forme. Goodale et Milner (1992) ont par la suite proposé que la voie dorsale, en plus de son implication dans le traitement de l’information visuo-spatiale, joue un rôle dans les ajustements sensori-moteurs nécessaires afin de guider les actions. Dans ce contexte, il est tout à fait plausible de considérer qu’un groupe de personne utilisant un langage sensori-moteur comme le langage des signes dans la vie de tous les jours, s’expose à une réorganisation cérébrale ciblant effectivement la voie dorsale. L’objectif de la première étude est d’explorer ces deux voies visuelles et plus particulièrement, la voie dorsale, chez des individus entendants par l’utilisation de deux stimuli de mouvement dont les caractéristiques physiques sont très similaires, mais qui évoquent un traitement relativement différent dans les régions corticales visuelles. Pour ce faire, un stimulus de forme définie par le mouvement et un stimulus de mouvement global ont été utilisés. Nos résultats indiquent que les voies dorsale et ventrale procèdent au traitement d’une forme définie par le mouvement, tandis que seule la voie dorsale est activée lors d’une tâche de mouvement global dont les caractéristiques psychophysiques sont relativement semblables. Nous avons utilisé, subséquemment, ces mêmes stimulations activant les voies dorsales et ventrales afin de vérifier quels pourraient être les différences fonctionnelles dans les régions visuelles et auditives chez des individus sourds profonds. Plusieurs études présentent la réorganisation corticale dans les régions visuelles et auditives en réponse à l’absence d’une modalité sensorielle. Cependant, l’implication spécifique des voies visuelles dorsale et ventrale demeure peu étudiée à ce jour, malgré plusieurs résultats proposant une implication plus importante de la voie dorsale dans la réorganisation visuelle chez les sourds. Suite à l’utilisation de l’imagerie cérébrale fonctionnelle pour investiguer ces questions, nos résultats ont été à l’encontre de cette hypothèse suggérant une réorganisation ciblant particulièrement la voie dorsale. Nos résultats indiquent plutôt une réorganisation non-spécifique au type de stimulation utilisé. En effet, le gyrus temporal supérieur est activé chez les sourds suite à la présentation de toutes nos stimulations visuelles, peu importe leur degré de complexité. Le groupe de participants sourds montre aussi une activation du cortex associatif postérieur, possiblement recruté pour traiter l’information visuelle en raison de l’absence de compétition en provenance des régions temporales auditives. Ces résultats ajoutent aux données déjà recueillies sur les modifications fonctionnelles qui peuvent survenir dans tout le cerveau des personnes sourdes, cependant les corrélats anatomiques de la surdité demeurent méconnus chez cette population. Une troisième étude se propose donc d’examiner les modifications structurales pouvant survenir dans le cerveau des personnes sourdes profondes congénitales ou prélinguales. Nos résultats montrent que plusieurs régions cérébrales semblent être différentes entre le groupe de participants sourds et celui des entendants. Nos analyses ont montré des augmentations de volume, allant jusqu’à 20%, dans les lobes frontaux, incluant l’aire de Broca et d’autres régions adjacentes impliqués dans le contrôle moteur et la production du langage. Les lobes temporaux semblent aussi présenter des différences morphométriques même si ces dernières ne sont pas significatives. Enfin, des différences de volume sont également recensées dans les parties du corps calleux contenant les axones permettant la communication entre les régions temporales et occipitales des deux hémisphères. / Due to the use of a mode of communication completely different from hearing people, Due to [the use of] a communication mode completely different from hearing people, the sign language and the absence of afferences from the auditory system, it is likely that significant functional and structural changes take place in the brains of profoundly deaf individuals. Previous studies suggest this reorganization may have greater impact on cortical structures located along the dorsal visual pathway than within the regions located inside the ventral pathway. The hypothesis, widely accepted by the scientific community, proposed by Ungerleider and Mishkin (1982) for the presence of two visual pathways in the occipital regions is also fairly contested. According to this hypothesis, one stream projecting from the striate cortex to the posterior parietal regions is involved in spatial vision and a second stream projecting to regions of the inferior temporal cortex underlying form recognition. Goodale and Milner (1992) subsequently proposed that the dorsal pathway, in addition to its involvement in the processing of visuospatial information, takes part in the necessary sensorymotor adjustments to guide actions. In this context, it is plausible to consider that a group of people using sensorimotor language (e.g., sign language) in their everyday life, the cerebral reorganization is more suited to target the dorsal pathway. The first objective of the study is to explore both visual pathways, especially the dorsal pathway, in hearing subjects by the use of two similar motion stimuli that evoke different types of processing. This was done with a form-from-motion stimuli and a global motion stimuli. Our results indicate that both dorsal and ventral pathways process forms defined by motion, while only the dorsal pathway is activated during a task of global motion whose psychophysical characteristics are relatively similar. Subsequently, we used these stimuli to activate the dorsal and ventral stream to investigate functional differences in the visual and auditory brain regions in profoundly deaf individuals. Several studies show cortical reorganization in the visual and auditory areas in response to the absence of a sensory modality. However, few studies have explored the specific involvement of dorsal and ventral visual streams, despite several results suggesting greater involvement of the dorsal pathway in visual reorganization with the deaf population. Following the use of functional brain imaging to investigate these issues, our results differed from the hypothesis suggesting a reorganization specifically targeting the dorsal pathway. Rather, our results indicate a non-specific reorganization to the different types of stimulations used. Indeed, the superior temporal gyrus was activated with the deaf following the presentation of our visual stimuli, regardless of their complexity. The group of deaf participants also showed activation of the posterior association cortex, possibly recruited to process visual information in the absence of competition from the temporal auditory regions. These results add to data already collected on the functional changes that may occur throughout the brains of deaf people, however, the anatomical correlates of deafness remains unknown in this population. A third study aimed to explore the structural changes occurring in the brains of prelingual and congenital profoundly deaf. Our results show that several brain regions appear to be different between the groups of participants composed of the deaf and hearing. Our analysis showed volume increases of up to 20% in the frontal lobe, including Broca's area and adjacent regions involved in motor control and language production. The temporal lobes also presented some morphometric differences even if they are not significant. Though not significant, the temporal lobes also presented some morphometric differences. Finally, differences in volume were also found in parts of the corpus callosum considered to carry fibers connecting the temporal and occipital lobes of both hemispheres.

L’acétylcholine (ACh) endogène de la corne dorsale de la moelle épinière (CDME) exerce une analgésie puissante utilisée en clinique, dont la source et les mécanismes demeurent inconnus. Elle siège probablement au niveau d’un plexus de fibres cholinergiques de la CDME d’origine non-élucidée. Dans ce contexte, nous avons pu établir que ce plexus est principalement issu d’interneurones cholinergiques spinaux caractérisés dans ces travaux, qui seraient donc le substrat probable de l’analgésie décrite. Décrits comme concourant aux effets aigus et analgésiques de la morphine, nous avons, par ailleurs, pu observer que les récepteurs de l’ACh participaient également aux effets chroniques et pro-algésique de la morphine, notamment au niveau de la CDME. Ceci place donc l’ACh comme un effecteur ou intermédiaire de la morphine.Nos travaux suggèrent ainsi que le système cholinergique spinal pourrait constituer une cible thérapeutique alternative pour de nouveaux traitements de la douleur / In the spinal cord dorsal horn (SCDH), endogenous acetylcholine (ACh) acts as a powerful analgesia, of clinical use. Though its source and mechanisms remain unravelled, this analgesia probably lies in a plexus of cholinergic fibers (PCF) located in the SCDH and of undetermined origin. In this context, we established that the PCF mainly originates from a spinal population of cholinergic interneurons, fully characterized in this work. These are, thus, the likely substrate of the spinal cholinergic analgesia.Besides, ACh receptors (AChR) partly mediate the analgesic acute effects of morphine. In this work, we also observed that a chronically-administered AChR agonist reproduces as well the pro-algesic effects of morphine in the same conditions. Thus, ACh appears as a possible intermediary or a final effecter of the morphine pain pathways.Our data suggest that the cholinergic system could become a new putative therapeutic target in pain management and treatment.

The aim of the work described in this thesis is to investigate the nature and mechanisms of action of repellent cues for growing axons. In particular I try to resolve the controversy in the literature regarding the need for protein synthesis in the growth cone in response to external guidance cues. My results resolve the conflicting data in the literature on Semaphorin-3A signalling, where differing labs had shown that inhibiting protein synthesis either blocks or has no effect upon repulsion. They demonstrate the presence of at least two independent pathways, protein synthesis-dependent mTOR activation and -independent GSK3? activation. The higher sensitivity of the synthesis-dependent pathway, and its redundancy at higher concentrations where synthesis-independent mechanisms can evoke a full collapse response alone, resolve the apparent conflict. My experiments also demonstrated that Nogo-?20, a domain of Nogo-A, requires local protein synthesis to cause collapse. Unlike Semaphorin-3A, the dependence of collapse upon protein synthesis is concentration-independent and does not involve guanylyl cyclase, but it does share a dependence upon mTOR activity and the synthesis of RhoA, sufficient to cause collapse downstream of Semaphorin-3A. The other axon-repelling domain of Nogo-A, Nogo-66, is partially dependent upon the proteasome instead. It does not share a common pathway with Nogo-?20, except that both are RhoA-dependent. I further attempted to identify the nature of a repulsive activity found in grey matter, ruling out a previously suggested candidate identity. Finally, I examined the phenomenon of nitric oxide-induced growth cone collapse. My experiments revealed that S-nitrosylated glutathione causes growth cone collapse through the activity of protein disulphide isomerase. This mechanism shows only a partial dependence upon soluble guanylyl cyclase, but I argue that it has total dependence upon an S-nitrosylated donor. Coupled with its apparent relation to S-palmitoylation, the reciprocal of S-nitrosylation, I propose that nitric oxide causes collapse by crossing the cell membrane to inhibit S-palmitoylation-determined localisation of proteins. These results reveal some of the many pathways involved in growth cone collapse, whose further characterisation may provide new targets for the treatment of injuries of the central nervous system.

<p>The question of whether second languages (L2s) are best learned implicitly or explicitly has been a topic of much empirical discourse, with the majority of studies pointing to the benefits of explicit instruction when learning L2 grammar rules. However, given the focus on grammar, it is unclear how generalizable these findings are to other linguistic domains, such as L2 speech and L2 vocabulary. The previous focus on laboratory-based settings, and the language bias in the literature, also make it unclear how ecologically valid and applicable these findings are to the real world. To address these macro research questions, two experiments were carried out on English-speaking L2 learners of German.</p> <p>Experiment I (ExI) investigated the effects of implicit and explicit learning on the acquisition of Final Obstruent Devoicing and Dorsal Fricative Assimilation. The effect of the two learning conditions on L2 perception was also measured using a perceptual discrimination task and a perceptual identification task. Experiment II (ExII) investigated the effects of explicit historical instruction on the learning of English-German cognates, which were compared to the effects of a non-explicit learning condition. To examine whether declarative knowledge of relevant historical changes can aid in vocabulary learning, an explicit condition received instruction on the Second Germanic Sound Shift, Ingvæonic Palatalization, and relevant historical semantic changes. Both experiments followed a pre-/post-/delayed-post-test design.</p> <p>Results indicate that the two explicit conditions significantly outperformed the non-explicit conditions, suggesting that explicit learning and explicit instruction can be beneficial when learning L2 speech and L2 vocabulary. In ExI, acoustic analyses of learner speech samples indicate that the explicit condition was more successful in the learning of the two phonological rules. In ExII, the explicit condition was more successful in the identification and learning of cognates, suggesting that knowledge of language history, and instruction on applied historical linguistics, can be beneficial when learning a language that is historically related to a language that learners already speak. The results from this dissertation are discussed in the context of implicit and explicit learning and instruction, the role of attention, and the role of declarative knowledge, with concluding remarks pointing to the importance of metacognitive and metalinguistic awareness in adult or university-level language courses.</p>

Acute spinal cord injury is often caused by collisions with motor vehicles, falls or violence. This injury could potentially lead to paraplegia or tetraplegia, causing great economic and personal loss. The patophysiology is biphasic, with primary and secondary mechanisms. Regarding secondary spinal cord injury, glutamate and interleukin-1 beta (IL-1<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cbeta" data-classname="equation" data-title="" />) activates N-methyl-d-aspartate (NMDA)-receptors leading to prolonged excitotoxity, causing neuronal death and subsequently glial scarring. Cross-linked-hyaluronic acid gel and interleukin-1 receptor antagonist (IL-1RA) are believed to have a neuroprotective effect. The major aim of this study was to evaluate neuroprotection in the central neural system. Briefly, spinal cord slice cultures from mice (p9-12) were chemically injured with NMDA and treated with two hyaluronic acid-based gels with integrated, or added, IL1RA. RNA was extracted and transcripted to cDNA. The gene expression of Neuronal nuclear protein, <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cbeta" data-classname="equation" data-title="" />-aktin and IL-1<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cbeta" data-classname="equation" data-title="" /> were studies with RT-qPCR. Results showed that gel integrated with IL1RA had significant therapeutic effect, resembling undamaged cultures. Furthermore, axonal outgrowth was investigated in dorsal root ganglion (DRG) in which two preparations of the method were evaluated. Results demonstrated that changing medium every other day was more preferred, compared to adding 20 µl medium every day.  In conclusion, gels integrated with IL1RA have neuroprotective properties and in DRG preparations, medium should be changed every other day for optimal results.

Indiana University-Purdue University Indianapolis (IUPUI) / Chronic inflammatory disorders are characterized by an increase in excitability of small diameter sensory neurons located in dorsal root ganglia (DRGs). This sensitization of neurons is a mechanism for chronic inflammatory pain and available therapies have poor efficacy and severe adverse effects when used chronically. Prostaglandin E₂ (PGE₂) is an inflammatory mediator that plays an important role in sensitization by activating G-protein coupled receptors (GPCRs) known as E-series prostaglandin receptors (EPs) coupled to the protein kinase A (PKA) pathway. EPs are known to downregulate upon prolonged exposure to PGE₂ or in chronic inflammation, however, sensitization persists and the mechanism for this is unknown. I hypothesized that persistence of PGE₂-induced hypersensitivity is associated with a switch in signaling caused by prolonged exposure to PGE₂ or the neurotrophin nerve growth factor (NGF), also a crucial inflammatory mediator. DRG cultures grown in the presence or absence of either PGE₂ or NGF were used to study whether re-exposure to the eicosanoid is able to cause sensitization and activate PKA. When cultures were grown in the presence of NGF, PGE₂-induced sensitization was not attenuated by inhibitors of PKA. Activation of PKA by PGE₂ was similar in DRG cultures grown in the presence or absence of NGF when phosphatase inhibitors were added to the lysis and assay buffers, but significantly less in cultures grown in the presence of NGF when phosphatase inhibitors were not added. In DRG cultures exposed to PGE₂ for 12 hours-5 days, sensitization after re-exposure to PGE₂ is maintained and resistant to PKA inhibition. Prolonged exposure to the eicosanoid caused complete loss of PKA activation after PGE₂ re-exposure. This desensitization was homologous, time dependent, reversible, and insurmountable by a higher concentration of PGE₂. Desensitization was attenuated by reduction of expression of G-protein receptor kinase 2 and was not mediated by PKA or protein kinase C. The presented work provides evidence for persistence of sensitization by PGE₂ as well as switch from the signaling pathway mediating this sensitization after long-term exposure to NFG or PGE₂.

Att utvärdera samband mellan subjektivt skattad smärta och transmittorsubstanser med magnetresonansspektroskopi Bakgrund: Smärta är en komplex upplevelse, som involverar olika delar av hjärnan. Regionen anterior cingulate cortex (ACC) är kopplad till upplevelsen av smärta och delas in i ett flertal mindre regioner, till exempel den pregenuala regionen (pgACC) och dorsala regionen (dACC). För att studera olika metaboliter och transmittorsubstanser kan magnetresonansspektroskopi (MRS) användas. MRS och sekvensen MEGA-PRESS kan mäta specifika transmittorsubstanser såsom Gamma-AminoButyric Acid (GABA) och glutamin-glutamat (Glx).  Motiv: Det finns kunskapsluckor kring hur individens subjektiva smärtupplevelse i relation till transmittorsubstanser objektivt kan mätas och utvärderas.  Syfte: Att med MRS och MEGA-PRESS undersöka GABA+ och Glx-nivåer i hjärnområdena pgACC och dACC samt undersöka samband mellan smärtkänslighet och GABA+ och Glx i pgACC och dACC.  Metod: En kvantitativ, experimentell pilotstudie genomfördes med tio friska deltagare. Initialt skannades deltagarna i MRT och smärtstimulerades, sedan skattade de den upplevda smärtan med hjälp av Numeric Rating Scale. MRS och tekniken MEGA-PRESS användes för att mäta transmittorsubstansnivåerna.   Resultat: Studien visade att det fanns en statistiskt signifikant negativ korrelation mellan skattad smärtintensitet och uppmätta nivåer av GABA+ i pgACC (Spearman´s rho = -0,67; p = 0,04). Det fanns även ett statistiskt signifikant positivt samband mellan skattad smärtintensitet och uppmätta nivåer av Glx i dACC (Spearman´s rho =0,73; p=0,02). Vidare fanns signifikant skillnad i Glx mellan pgACC och dACC och en icke signifikant skillnad i GABA+.  Konklusion: Sammanfattningsvis visar resultatet att MRS och MEGA-PRESS kan kvantifiera transmittorsubstanser vid utvärdering av smärtkänslighet och att det finns en positiv korrelation mellan Glx och skattad smärtintensitet, samt en negativ korrelation mellan GABA+ och skattad smärtintensitet. Detta kan ge fördjupad insikt i individens smärtupplevelse och kan främja den individuella behandlingen. Genom att ta hänsyn till sambandet mellan smärta och transmittorsubstanser kan det bidra till ökad förståelse kring individens smärtupplevelse. / To evaluate the relation between subjectively estimated pain and neurotransmitters using magnetic resonance spectroscopy  Background: Pain is a complex experience that involves different parts of the brain. The region anterior cingulate cortex (ACC) is connected to the experience of pain and can be divided into several smaller areas, such as the pregenual region (pgACC) and the dorsal region (dACC). To study different metabolites and neurotransmitters, magnetic resonance spectroscopy (MRS) can be used. MRS and the sequence (MEGA-PRESS) can measure specific neurotransmitters such as Gamma-AminoButyric Acid (GABA) and glutamin-glutamate (Glx).  Motive: There are knowledge gaps about how the individual's subjective pain experience in relation to neurotransmitters can be objectively measured and evaluated.  Aim: Using MRS and MEGA-PRESS to examine levels of GABA+ and Glx in the brain regions pgACC and dACC and to examine the relationship between pain sensitivity and GABA+ and Glx in pgACC and dACC.  Methods: A quantitative, experimental pilot study was conducted which included ten healthy participants. The participants were initially scanned in the MRI and subjected to pain-stimulation, thereafter the participants rated the perceived pain using Numeric Rating Scale. MRS and the sequence MEGA-PRESS were used to quantify the neurotransmitters of interest.  Result: There was a significant, negative correlation between rated pain intensity and measured GABA+ levels in pgACC (Spearman´s rho = -0,67; p = 0,04). There was also a significant, positive correlation between rated pain intensity and measured levels of Glx in dACC (Spearman´s rho =0,73; p=0,02). Furthermore, there was a significant difference in Glx between pgACC and dACC as well as a non-significant difference in GABA+ between regions.  Conclusion: In summary, the result shows that MRS and MEGA-PRESS can quantify neurotransmitters when evaluating pain sensitivity and that there is a positive correlation between Glx and estimated pain intensity, and also a negative correlation between GABA+ and estimated pain intensity. This can provide a deeper insight into the individual’s pain experience and promote individual treatment. Further research regarding the meaning of the different brain regions when measuring neurotransmitters is recommended.

No description available.