There remains a high degree of scepticism about acupuncture since its theoretical basis has no clear reference in Western medical and scientific terms, making any associations between neurophysiology and specific acupuncture concepts difficult to determine. Using neuroimaging and engineering approaches to understand its physiological basis may engender greater acceptance of and improvement in the clinical application of acupuncture. Research into the efficacy of acupuncture has raised a number of difficult methodological issues, particularly in relation to the selection of appropriate controls. Separating specific effects from non-specific effects is complex because acupuncture is a physical, invasive, manual procedure involving time and ritual. Sham acupuncture results show only the difference between sham and real acupuncture not the real affect of acupuncture, and other controls may produce distinct subjective and objective effects. Point injection (the injection of a small amount of a substance at an acupoint), a recent innovation of traditional acupuncture, aims to enhance and prolong the stimulation effect in a standardised, reproducible manner. By providing precise, measurable acupoint stimulation applied incrementally in a specifically designed paradigm, an acupoint could act as its own control. This firstly requires injection to be validated against traditional needling. Aims 1. To develop an instrument for reproducible saline delivery at an acupoint. 2. To cross-validate saline acupoint injection (PI) with traditional needle acupuncture (TA). 3. To demonstrate central nervous system (CNS) effects of acupuncture both in health and chronic pain. Hypothesis The primary hypothesis is that stimulation of specific acupoints with linearly incremental saline injection produces differential effects within the CNS observable with functional magnetic resonance imaging (fMRI) allowing investigation of acupuncture in health and chronic pain. Novelty As neuroimaging has not yet clearly defined the brain structures that may be modulated by acupuncture, this project is exploratory in nature. It is expected that acupuncture effects can be robustly imaged with fMRI in healthy subjects and those suffering chronic pain. The demonstrated effects will result from the acupuncture process of progressive point stimulation by tissue distension rather than needle insertion or biological noise. It is proposed to examine the putative modulation of pain by acupuncture within the extensively mapped neuromatrix of cortical and subcortical regions, including the somatic, insula, and limbic cortices, and thalamus. Detailed information regarding differences in brain response between acupuncture in normal and diseased states will expand understanding of acupuncture as a clinical tool. The dilemma of sham stimulation or arbitrary controls will be addressed by confirming PI as a valid, reproducible stimulation method. Methods and Results A series of empirical experiments was designed and conducted to determine the effects of stimulation of different acupoints. 1. Chapters 1 and 3 outline the current understanding of acupuncture in the Western milieu and a review of the neuroimaging literature respectively. 2. In Chapter 2, the report of PI tested against TA in healthy volunteers to determine equivalence of physiological effect demonstrates no statistically significant differences between the methodologies. 3. Chapter 4 reports the design and validation of a task specific microprocessor controlled syringe driver. 4. Four differing acupoints were tested during an fMRI experiment described in Chapter 5; different activation areas were demonstrated across the acupoints providing early support for the hypothesis that different acupoints may have different effects. A subset of brain areas recognised within the pain neuromatrix was delineated, congruent spatially and directionally with those reported in pharmacological analgesia studies. 5. As outlined in Chapter 6, heart rate variability can be measured rapidly in a stressful environment to provide meaningful data on the response of the autonomic nervous system to acupuncture stimulation. 6. The hypothesis of different acupoints having different effects was tested in subjects suffering chronic pain by contrasting an accepted and a neutral acupoint, the results being reported in Chapter 7. Conclusion Despite a long history of clinical usage, appropriate scientific studies have not yet addressed the basic effectiveness and efficacy of acupuncture. This thesis presents a series of empirical studies designed to address a number of the questions arising in the literature and provides converging evidence of the manner in which different acupoints modulate the CNS, specifically within the pain neuromatrix.

There remains a high degree of scepticism about acupuncture since its theoretical basis has no clear reference in Western medical and scientific terms, making any associations between neurophysiology and specific acupuncture concepts difficult to determine. Using neuroimaging and engineering approaches to understand its physiological basis may engender greater acceptance of and improvement in the clinical application of acupuncture. Research into the efficacy of acupuncture has raised a number of difficult methodological issues, particularly in relation to the selection of appropriate controls. Separating specific effects from non-specific effects is complex because acupuncture is a physical, invasive, manual procedure involving time and ritual. Sham acupuncture results show only the difference between sham and real acupuncture not the real affect of acupuncture, and other controls may produce distinct subjective and objective effects. Point injection (the injection of a small amount of a substance at an acupoint), a recent innovation of traditional acupuncture, aims to enhance and prolong the stimulation effect in a standardised, reproducible manner. By providing precise, measurable acupoint stimulation applied incrementally in a specifically designed paradigm, an acupoint could act as its own control. This firstly requires injection to be validated against traditional needling. Aims 1. To develop an instrument for reproducible saline delivery at an acupoint. 2. To cross-validate saline acupoint injection (PI) with traditional needle acupuncture (TA). 3. To demonstrate central nervous system (CNS) effects of acupuncture both in health and chronic pain. Hypothesis The primary hypothesis is that stimulation of specific acupoints with linearly incremental saline injection produces differential effects within the CNS observable with functional magnetic resonance imaging (fMRI) allowing investigation of acupuncture in health and chronic pain. Novelty As neuroimaging has not yet clearly defined the brain structures that may be modulated by acupuncture, this project is exploratory in nature. It is expected that acupuncture effects can be robustly imaged with fMRI in healthy subjects and those suffering chronic pain. The demonstrated effects will result from the acupuncture process of progressive point stimulation by tissue distension rather than needle insertion or biological noise. It is proposed to examine the putative modulation of pain by acupuncture within the extensively mapped neuromatrix of cortical and subcortical regions, including the somatic, insula, and limbic cortices, and thalamus. Detailed information regarding differences in brain response between acupuncture in normal and diseased states will expand understanding of acupuncture as a clinical tool. The dilemma of sham stimulation or arbitrary controls will be addressed by confirming PI as a valid, reproducible stimulation method. Methods and Results A series of empirical experiments was designed and conducted to determine the effects of stimulation of different acupoints. 1. Chapters 1 and 3 outline the current understanding of acupuncture in the Western milieu and a review of the neuroimaging literature respectively. 2. In Chapter 2, the report of PI tested against TA in healthy volunteers to determine equivalence of physiological effect demonstrates no statistically significant differences between the methodologies. 3. Chapter 4 reports the design and validation of a task specific microprocessor controlled syringe driver. 4. Four differing acupoints were tested during an fMRI experiment described in Chapter 5; different activation areas were demonstrated across the acupoints providing early support for the hypothesis that different acupoints may have different effects. A subset of brain areas recognised within the pain neuromatrix was delineated, congruent spatially and directionally with those reported in pharmacological analgesia studies. 5. As outlined in Chapter 6, heart rate variability can be measured rapidly in a stressful environment to provide meaningful data on the response of the autonomic nervous system to acupuncture stimulation. 6. The hypothesis of different acupoints having different effects was tested in subjects suffering chronic pain by contrasting an accepted and a neutral acupoint, the results being reported in Chapter 7. Conclusion Despite a long history of clinical usage, appropriate scientific studies have not yet addressed the basic effectiveness and efficacy of acupuncture. This thesis presents a series of empirical studies designed to address a number of the questions arising in the literature and provides converging evidence of the manner in which different acupoints modulate the CNS, specifically within the pain neuromatrix.

Functional Magnetic Resonance Imaging (fMRI) based studies are rapidly expanding in the field of preclinical research. The majority of these studies use Echo Planar Imaging (EPI) to measure Blood Oxygenation Level Dependent (BOLD) signal contrasts in the brain. In such studies the magnitude and statistical significances of these contrasts are then related to brain function and cognition. It is assumed that any observed signal contrast is ultimately due to differences in biological state and that scanner performance is stable and repeatable between subjects and studies. However, due to confounding issues introduced by in vivo subjects, little work has been undertaken to test this basic assumption. As the BOLD signal contrasts generated in such experiments are often very low, even small changes in scanner performance may dominate the BOLD contrast, distorting any biological conclusions drawn. A series of fMRI phantoms were produced to measure scanner performance independent of biological subjects. These phantoms produce specified signal contrast levels on demand during an fMRI scan by means of current-induced magnetic field gradients. These were used to generate data sets that emulated the BOLD signal contrast of in vivo imaging. Two studies examining scanner performance were then conducted on high-field preclinical MRI scanners. Firstly, in a longitudinal study on a single scanner, measurements were taken over a number of days across a week long period and then every two months over a year long period. Secondly, the behaviour of four preclinical scanners (three at 7T, one at 9.4T) was comparatively assessed. Measurements of several imaging parameters including contrast generated and functional contrast to noise ratio (fCNR) were obtained in both studies. If the scanners involved are truly comparable then they should generate similar measurement values. Across both studies parameter measurements showed significant differences for identical contrast settings on the phantom. Although signal contrast itself proved very comparable across the studies fCNR proved to be highly variable. As well as these measurements of longer tem behaviour proving variable, short and mid-term signal stability displayed a wide range of variability. Variations in the level and quality of both signal and noise were observed. Modelling of signal changes based on fundamental physical principles was also performed for comparison. The impact of these behaviours and variations on in vivo studies could result in skewed biological conclusions at any single site, with some sites exhibiting greater problems than others. The multisite results suggest potential difficulties when comparing biological conclusions between sites, even when using identical imaging parameters. In summary, these results suggest that a cautious approach should be taken with the conclusions of both fMRI and associated resting state connectivity studies that use EPI as their acquisition sequence. Improvements to both the experimental design of studies and regular quality monitoring of scanners should be undertaken to minimise these effects. Clinical MRI scanners should also be assessed for similar aberrations in behaviour.

This thesis is concerned with the age-related changes in working memory (WM), and the inter-individual differences in cognitive and neural mechanisms that correspond to healthy versus poor ageing of WM function. The first half of this thesis focusses on the age-related decline in WM and whether preserved top-down attentional control could mitigate such deficits. In Chapter 2, I present a functional MRI study showing that older adults reliably recruit brain networks that subserve cognitive control, which work in concert with the task relevant sensory areas during effective selective WM. In Chapter 3, I show that older adults retain flexible control over WM representations, and this ability corresponded to the reliable recruitment of neural signals of orienting attention qualitatively similar to those observed in younger adults. Magnetoencephalographic recordings showed that the neural dynamics during orienting attention within WM was predictive of good performance, demonstrating that the more efficient the process of orienting within WM to select the target item, the better the memory representation can be preserved for upcoming behaviour. In the second half of this thesis, I explored whether WM for affective content has a special status in healthy ageing. In Chapter 4, I developed an emotional WM precision task to measure WM abilities for emotional content appropriate for elderly adults. In Chapter 5, I tested a group of young and older adults on WM and perceptual-matching abilities for emotional faces. The results suggest that older adults show a general impairment in task performance, but possibly with some preservation in the ability to maintain emotional content in WM. There were marked differences in how the emotional information was processed between age groups, in which older adults have a tendency to represent negative stimuli as less negative than younger adults in perception and WM, and tended to show a positive interpretation of the valence of more ambiguous emotional stimuli. In Chapter 6, I summarise the findings presented in this thesis, discuss the implications of the key findings, and consider some suggestions for future studies that aim to elucidate the mechanisms of WM in healthy ageing.

Our senses, while limited, shape our perception of the world and contribute to the functional architecture of the brain. This dissertation investigates the role of sensory modality and task demands in the cortical organization of healthy human adults using functional magnetic resonance imaging (fMRI). This research provides evidence for sensory modality bias in frontal cortical regions by directly contrasting auditory and visual sustained attention. This contrast revealed two distinct visual-biased regions in lateral frontal cortex - superior and inferior precentral sulcus (sPCS, iPCS) - anatomically interleaved with two auditory-biased regions - transverse gyrus intersecting precentral sulcus (tgPCS) and caudal inferior frontal sulcus (cIFS). Intrinsic (resting-state) functional connectivity analysis demonstrated that sPCS and iPCS fall within a broad visual-attention network, while tgPCS and cIFS fall within a broad auditory-attention network. Unisensory (auditory or visual) short-term memory (STM) tasks assessed the flexible recruitment of these sensory-biased cortical regions by varying information domain demands (e.g., spatial, temporal). While both modalities provide spatial and temporal information, vision has greater spatial resolution than audition, and audition has excellent temporal precision relative to vision. A visual temporal, but not a spatial, STM task flexibly recruited frontal auditory-biased regions; conversely, an auditory spatial task more strongly recruited frontal visual-biased regions compared to an auditory temporal task. This flexible recruitment extended to an auditory-biased superior temporal lobe region and to a subset of visual-biased parietal regions. A demanding auditory spatial STM task recruited anterior/superior visuotopic maps (IPS2-4, SPL1) along the intraparietal sulcus, but neither spatial nor temporal auditory tasks recruited posterior/interior maps. Finally, a comparison of visual spatial attention and STM under varied cognitive load demands attempted to further elucidate the organization of posterior parietal cortex. Parietal visuotopic maps were recruited for both visual spatial attention and working memory but demonstrated a graded response to task demands. Posterior/inferior maps (IPS0-1) demonstrated a linear relationship with the number of items attended to or remembered in the visual spatial tasks. Anterior/superior maps (IPS2-4, SPL1) demonstrated a general recruitment in visual spatial cognitive tasks, with a stronger response for visual spatial attention compared to STM.

A percepção de esforço (PSE) e a fadiga tem grande participação do cérebro durante o exercício físico, no entanto, pouco se sabe quanto às áreas associadas a essas respostas. Dessa forma, o presente estudo teve como objetivo identificar e comparar as áreas cerebrais associadas à percepção de esforço durante exercício de ciclismo em diferentes intensidades e níveis de treinamento. Participaram do estudo 24 sujeitos adultos; 12 ciclistas (75,6 ± 8,4 kg; 175 ± 5,3 cm; 24,4 ± 7,1 anos; atividade física 5,4 ± 1,5 vezes por semana) e 12 não ciclistas (treinados) (79,7 ± 10,5 kg; 177 ± 9,1 cm; 27,4 ± 4,8 anos; atividade física 2,3 ± 1,3 vezes por semana). Os sujeitos foram posicionados ao ergômetro de ciclismo acoplado a ressonância magnética e realizaram um teste intervalado de carga incremental constituído por blocos de 30 s intervalados por 30 s de repouso. Ao término de cada bloco a percepção de esforço foi reportada. As análises comparativas das imagens foram todas geradas no Matlab através dos softwares SPM e NCA. Foi considerado para análise das imagens o período de 4 s imediatamente ao final de cada bloco de exercício com o objetivo de verificar as áreas relacionadas com o processamento da PSE. As seguintes áreas relacionadas à percepção de esforço foram ativadas: giro cingulado, giro pré-central, giro pós-central, giro frontal superior, giro frontal superior, lóbulo superior parietal, giro lingual, giro temporal médio, giro frontal médio, precuneus, cuneus e cerebelo. De forma complementar, as áreas inibidas foram: giro angular, giro temporal superior, giro temporal médio, giro pré-central, giro temporal superior, giro frontal médio, giro occipital médio, giro lingual, lóbulo paracentral, precuneus e tálamo. Essas áreas ativadas e inibidas estão associadas a uma resposta cognitiva, ou seja, o momento que o indivíduo reportava a percepção de esforço diante de um protocolo de exercício incremental, considerando todas as intensidades. Em intensidades baixas houve ativação do cerebelo e giro pós-central, e inibição do giro frontal médio e giro temporal superior. Em intensidades altas, houve uma ativação do giro cingulado e inibição do giro angular e precuneus. Na comparação entre as intensidades podemos destacar que em intensidades baixas houve maior ativação do lóbulo parietal superior. Por outro lado, em intensidades altas houve maior inibição do giro angular, cingulado posterior, lóbulo parietal inferior e precuneus. Quando comparados indivíduos ciclistas e saudáveis houve uma maior ativação do giro pré-central e maior inibição do giro pré-central, giro temporal inferior e cerebelo nos ciclistas considerando todas as intensidades. Por fim, na comparação entre ciclistas e treinados, nas intensidades altas houve maior inibição do giro temporal médio (giro fusiforme) nos ciclistas. As áreas cerebrais, ativadas e inibidas, associadas à percepção de esforço estão relacionadas à área motora, pré-motora, motor suplementar somatossensoriais, controle emocional, processamento de atenção, linguagem, auditivas, integração de informação, gerenciamento de memória, planejamento e resolução de problemas e cognitiva. Em intensidades baixas, áreas motoras e somatossensorias foram ativadas e houve inibição de área pré-frontal e auditiva. Por outro lado, em intensidades altas, foram ativadas áreas relacionadas com o controle de emoções e foram inibidas áreas relacionadas ao processamento de linguagem e memória episódica. Entre ciclistas e não ciclistas, houve maior ativação de área motora e maior inibição de área somatossensorial, processamento de atenção e motora / Perception of effort and fatigue are widely represented in the brain during exercise, however, the information is not clear about the areas associated with these responses. Thus, this study aimed to identify and compare the brain areas associated with perception of effort during cycling exercise at different intensities and levels of training. This study included 24 adult subjects; 12 cyclists (75.6 ± 8.4 kg, height 175 cm ± 5.3, 24.4 ± 7.1 years; physical activity 5.4 ± 1.5 times per week) and 12 non-cyclists (trained) (79.7 ± 10.5 kg; 177 cm ± 9.1, 27.4 ± 4.8 years; physical activity 2.3 ± 1.3 times per week). Subjects were positioned to cycling ergometer coupled to magnetic resonance equipment and performed an incremental load interval test comprising blocks 30 s intervals for 30 s rest. At the end of each block, the perception of effort was reported. Comparative analysis of the images was all generated in Matlab using the SPM and NCA software. The following areas related to perceived exertion were activated: cingulate gyrus, precentral gyrus, post-central gyrus, superior frontal gyrus, superior frontal gyrus, parietal upper lobe, gyrus lingual, middle temporal gyrus, middle frontal gyrus, precuneus, cuneus and cerebellum. Complementarily, these were inhibited areas: angular gyrus, superior temporal gyrus, middle temporal gyrus, precentral gyrus, superior temporal gyrus, middle frontal gyrus, middle occipital gyrus, gyrus lingual, paracentral lobule, precuneus and thalamus. These activated and inhibited areas are related to cognitive response, when the individual reported the perceived exertion on an incremental exercise protocol, considering all intensities. At low intensities, there was activation of the cerebellum and post-central gyrus, and inhibition of the middle frontal gyrus and superior temporal gyrus. At high intensities, there was an activation of the cingulate gyrus and inhibition of angular and precuneus spin. Comparing the intensities, there was greater activation in the superior parietal lobe at low intensities. On the other hand, high intensity demonstrated greater inhibition of the angular gyrus, posterior cingulate, inferior parietal lobule and precuneus. Compared trained and healthy individuals there was a greater activation of the precentral gyrus and greater inhibition of pre-central gyrus, inferior temporal gyrus and cerebellum in trained subjects considering all intensities. Finally, comparing trained healthy subjects at high intensities there was greater inhibition of medial temporal gyrus (fusiform gyrus) in trained individuals. The brain areas, activated and inhibited, associated with the perception of effort are related to motor, pre-motor, somatosensory supplemental motor, emotional control, attention processing, language, auditory, information integration, memory management, planning and resolution problems and cognitive. At low intensities, motor and somatosensory areas were activated and there was inhibition of the prefrontal and auditory area. On the other hand, at high intensities, areas related to the control of emotions were activated and areas related to language processing and episodic memory were inhibited. Between cyclists and non-cyclists, there was greater activation of motor area and greater inhibition of somatosensory area, attention and motor processing

Orientador: Gabriela Castellano / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-15T20:04:30Z (GMT). No. of bitstreams: 1 Dias_CarlosSatoBaraldi_M.pdf: 2085782 bytes, checksum: 169421816d56753ab8dbb39c00e0a51f (MD5) Previous issue date: 2010 / Resumo: A técnica de espectroscopia por ressonância magnética (MRS, do inglês Magnetic Resonance Spectroscopy)baseada no núcleo do hidrogênio (1 H -MRS)tem sido muito usada em estudos neurológicos na determinação de padrões metabólicos para várias patologias. A informação fornecida por esta técnica é única, pois permite monitorar níveis de metabólitos específicos, envolvidos em vários aspectos da função cerebral. Até o momento, a grande maioria dos estudos de 1 H -MRS in vivo têm sido "estáticos ", no sentido de que uma única medida é feita, sem se preocupar com informação temporal. Isso se deve à baixa razão sinal-ruído inerente a esta técnica, que obriga à realização de aquisições longas e médias temporais, sacrificando a resolução temporal. No entanto,o advento da técnica de ressonância magnética funcional e de outras técnicas de neuroimagem dinâmicas, que medem parâmetros dinâmicos como fluxo sanguíneo, taxa de oxigenação do sangue, atividades elétrica e magnética do cérebro, naturalmente fez surgir o interesse em se ter uma técnica que pudesse fornecer informação dinâmica sobre as vias metabólicas associadas à função cerebral - uma MRS funcional. O objetivo deste trabalho foi, portanto, verificar a viabilidade da utilização da técnica de MRS in vivo em experimentos funcionais, tendo sido o primeiro realizado nesta área, no Brasil. Para isso foi primeiramente realizado um estudo extensivo sobre os poucos trabalhos existentes na área e as bases bioquímicas da ativação neuronal. Em seguida, foram realizados experimentos e desenvolvidos vários métodos de análise para tentar detectar a variação temporal dos principais metabólitos presentes num espectro cerebral (N-acetil-aspartato total: NAA, Creatina total: Cre, grupo Colina: Cho, grupo Glutamato/Glutamina: Glx, e Lactato: Lac)em indivíduos saudáveis, durante um experimento com estímulo visual. Os experimentos apresentaram uma série de dificuldades, e não foi possível alcançar a alta resolução temporal desejada, sendo que a resolução média ficou na ordem de minutos -o que concorda, no entanto, com a maioria dos trabalhos encontrados na literatura. Não detectamos variações significativas nos níveis de NAA, Cre e Cho, o que também está de acordo com a maioria dos estudos encontrados na literatura. Por outro lado, foram encontradas variações nos níveis de Lac (que aumentaram com o estímulo, o que concorda com a literatura, porém não voltaram ao nível basal após o estímulo, o que não concorda), e variações nos níveis do grupo Glx (que aumentaram com o estímulo, voltando em seguida ao nível basal, o que concorda com a literatura). Embora os resultados encontrados não tenham sido totalmente concordantes com a literatura e não tenha sido possível melhorar a resolução temporal (em relação aos trabalhos da literatura), acreditamos que este trabalho deixa uma significativa contribuição através dos diversos protocolos experimentais e métodos de análise testados, e abre o caminho para pesquisas futuras na área / Abstract: The technique of Magnetic Resonance Spectroscopy using the hydrogen nucleus (1 H -MRS) has been widely used for neurologic research for determining metabolic patterns for many pathologies. The type of information provided by this technique is unique, since it allows monitoring specific metabolic concentrations involved in cerebral function.Until now, the majority of the in vivo 1 H -MRS studies have been "static ", meaning that data acquisition is done with no concern for temporal information. The reason for this is the low signal-to-noise ratio (SNR)inherent to this technique, which imposes long acquisitions and time averaging that sacrifices temporal resolution. However, the development of function Magnetic Resonance Imaging (fMRI)and other time resolved neuroimaging techniques, that measure dynamic parameters such as blood flow, blood oxygenation rate, electric and magnetic cerebral activity, naturally brought up the interest on a technique that would allow a time resolved measure of the specific metabolic concentrations involved on cerebral metabolism - something like a functional MRS. Therefore the goal of this work was to study the feasibility of using the in vivo MRS technique for functional experiments, being the .rst of its kind performed in Brazil.To do so,initially an extensive bibliographic research was done, to comprehend not only the details of these experiments but also the neurochemistry behind the MRS signal.Next, experiments were performed and many analysis methods were developed, in order to attempt to detect temporal variations of the main metabolites present on a typical cerebral spectrum (total N-acetyl-aspartic acid: NAA, total Creatine: Cre, total Choline: Cho, Glutamine/Glutamate group: Glx and Lactate: Lac) in healthy subjects, during a visual stimulation experiment. Those experiments presented a series of difficulties and the desired high temporal resolution was not attained, achieving an average resolution of minutes - the same resolution found on the majority of the works published. We did not detect any significant variation of the NAA, Cre or Cho levels, which supports the conclusions of other works published. On the other hand, we detected variations in the Lactate levels (which increased with the stimulus, as reported in other works, but did not return to base-line levels, which disagrees with the published works), and in the Glx levels (which increased with the stimulus, returning to baseline levels after it, which agrees with the published literature). Although the results found are not totally in agreement with the published literature and it was not possible to improve the temporal resolution (compared to published works), we believe that this work leaves a significant contribution to the field, through the experimental protocols and analysis methods tested, and opens paths for future research in this area / Mestrado / Física / Mestre em Física

The default mode network (DMN) consists of a set of interconnected brain regions supporting autobiographical memory, our concept of the self, and the internal monologue. These processes must be maintained at all times and consume the highest amount of the brain’s energy during its baseline state. However, when faced with an active, externally-directed cognitive task, the DMN shows a small, but significant, decrease in activity. The reduction in DMN activity during the performance of an active, externally-directed task compared to a baseline state is termed task-induced deactivation (TID), which is thought to ‘free-up’ resources required to respond to external demands. However, older adults show a reduced level of TID in the DMN. Recently, it has begun to be appreciated that this decrease in TID may be associated with poorer cognitive performance, especially during tasks placing high demands on executive function (EF). Diminished DMN TID has not only been associated with increasing age but also with multiple age-related neurobiological correlates such as accumulating Alzheimer’s disease (AD) pathology and reductions in white matter (WM) connectivity. However, these biological factors—age, WM connectivity reductions and increasing AD pathology—are themselves related. Based on the literature, we hypothesized that declining WM connectivity may represent a common pathway by which both age and AD pathology contribute to diminished DMN TID. Further, we hypothesized that declines in DMN function and WM connectivity would predict poorer in EF. Three experiments were carried out to test these hypotheses. Experiment 1 tested whether WM connectivity predicted the level of DMN TID during a task requiring a high level of EF. Results from 117 adults (ages 25-83) showed that WM connectivity declined with increasing age, and that this decline in WM connectivity was directly associated with reduced DMN TID during the task. Experiment 2 tested whether declines in WM connectivity explained both age-related and AD pathology-related declines in DMN TID. Results from 29 younger adults and 35 older adults showed that declining WM connectivity was associated with increasing age and AD pathology, and that this decline in WM connectivity was a common pathway for diminished DMN TID associated with either aging or AD pathology. Experiment 3 investigated whether measures of WM connectivity and DMN TID at baseline could predict EF measured using clinically-used tests. Results from 29 older adults from Experiment 2 showed that less DMN TID predicted poorer EF at baseline and diminished WM connectivity at baseline predicted a greater decline in EF after 3 years. Further, WM connectivity explained reductions in EF predicted by baseline AD pathology, as well as further reductions in EF not predicted by baseline AD pathology. Together the results of these studies suggest that WM connectivity is a key pathway for age-related and AD pathology-related patterns of diminished DMN TID associated with poorer EF. Further, WM connectivity may represent a potential therapeutic target for interventions attempting to prevent future declines in EF occurring in aging and AD.

Orientador: Paula Teixeira Fernandes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-24T10:11:07Z (GMT). No. of bitstreams: 1 Castanho_GabrielaKaiserFullin_M.pdf: 2680275 bytes, checksum: d8146be4deb23a380916dab5e59d52c2 (MD5) Previous issue date: 2014 / Resumo: O consumo de carboidrato (CHO) está relacionado com melhor desempenho esportivo. Por vias diretas ou indiretas o substrato mantém a glicemia, poupa glicogênio, repõe glicogênio muscular e, ainda, exerce papel importante no cérebro como fonte de energia, podendo melhorar a função neural durante exercício físico. Com o consumo de CHO é possível que haja diferenciação na ativação de áreas cerebrais relacionadas ao desempenho no exercício. Com isso, esse estudo objetivou avaliar o efeito do consumo de CHO na ativação cerebral durante exercício físico realizado durante aquisição de ressonância magnética funcional (RMf). Foram voluntários 10 ciclistas do sexo masculino que realizaram um protocolo de pedalada em cicloergômetro acoplado à RMf, consumindo de 50g de carboidrato ou solução placebo no intervalo de duas séries de exercício. Os resultados mostraram que o CHO apresentou um importante papel nas áreas cerebrais durante o exercício, ativando áreas relacionadas à tomada de decisões (insula) e motivação (sistema límbico) e desativando principalmente áreas dos lobos frontal e parietal. Com o consumo de placebo também houve ativação de áreas importantes no psicológico do individuo (cíngulo posterior). Independente da substância consumida, a ativação após o consumo de bebida mostrou importante relação com áreas relacionadas à continuidade do exercício como giro do cíngulo quando comparado ao controle. Durante todo o estudo as áreas responsáveis pela iniciação e manutenção dos movimentos, localizadas principalmente no lobo frontal e cerebelo, apresentaram-se ativas. Os resultados entre o consumo do placebo e o momento controle mostraram que a substância placebo não trouxe diferença de ativação neural, sendo que o inverso ocorreu na comparação entre CHO e controle. O CHO ativou áreas de extrema importância na continuidade do exercício como o giro do cíngulo e cíngulo anterior, mostrando que a suplementação pode ter influências no cérebro durante o exercício que melhore o rendimento. Portanto, o CHO mostrou efetividade como suplemento esportivo também na atividade cerebral, mostrando importância para a prática de exercício e a melhora do rendimento. Assim conseguimos aprofundar o conhecimento da atuação de nutrientes no cérebro durante o exercício / Abstract: The consumption of carbohydrate (CH) is related to better sports performance. By direct or indirect way the substrate maintains blood glucose, glycogen saves, restores muscle glycogen, and also plays an important role in the brain as an energy source, thus improving neural function during exercise. With the consumption of CH is possible that there is differentiation in the activation of brain areas related to exercise performance. The study aimed to evaluate the effect of CH consumption in brain activation during exercise performed during acquisition of functional magnetic resonance imaging (fMRI). Volunteers were six male cyclists who performed a protocol cycleergometer coupled to fMRI, consuming 50g of carbohydrate or placebo solution in the range of two series of exercise. The results showed that the CHO had an important role in brain areas during exercise, activating related decision making (insula) and motivation (limbic system) areas and mostly disabling areas of the frontal and parietal lobes. With the use of placebo was also significant activation in areas of individual psychological (posterior cingulate). Independent of substance, activation after beverage consumption showed a significant relationship with the continuity of exercise as the cingulate gyrus area, when compared to the control. Throughout the study the areas responsible for the initiation and maintenance of motion, located mainly in the cerebellum and frontal lobe had become active. The results between the placebo and the control group showed that the difference did not had neural activation, and the opposite occurred when comparing CHO and control. The CHO activated areas of extreme importance in the continuity of the company as the cingulate gyrus and anterior cingulate cortex, showing that supplementation may have influences in the brain during exercise to improve performance. Therefore, the CHO has shown effectiveness as a sports supplement also in brain activity important for exercise training results and greater efficiency. Thus we could deepen the understanding of the action of nutrients in the brain during exercise / Mestrado / Atividade Fisica, Adaptação e Saude / Mestra em Educação Física

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13387号 / 論医博第2219号 / 新制||医||1048(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 溝脇 尚志, 教授 髙橋 良輔, 教授 渡邉 大 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM