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This systematic review aims to investigate the effects of aerobic exercise on the neuroal basis of memory functions in healthy elderly individuals. The search was conducted in accordance with PRISMA and covered three electronic databases, namely PubMed, Scopus, and Web of Science, for peer-reviewed published, and original research. Six studies met the inclusion criteria and were included in the review. The studies utilized various behavioral or cognitive tasks related to memory, including the Sternberg Working Memory Task, Spatial Memory tests, and neuroimaging techniques such as magnetic resonance imaging (MRI). This systematic review suggests that aerobic exercise can improve memory in healthy elderly individuals, including spatial, working, and short- and long-term memory. As revealed by neuroimaging techniques, memory function improvement was accompanied by changes in brain structure and function in memory-processing regions. These findings provide evidence that aerobic exercise can improve the neurological basis of memory function in healthy elderly individuals. The beneficial effects of aerobic exercise on memory have significant implications for the aged population. Memory loss is a common and often debilitating issue in older adults, and the ability to recall and learn new information is crucial for maintaining independence and quality of life. Therefore, aerobic exercise is a promising intervention to improve memory function in healthy elderly individuals.

The human cerebral cortex, the outermost layer of the brain, is typically considered in imaging studies to consist of grey matter (GM), with white matter (WM) lying below it. With better imaging techniques, a third tissue type, found between GM and WM, can be identified. This layer contains myelinated axons and is found in the cortex, thus we call it intracortical myelin (ICM), or myelinated grey matter (GMm). We examined the cortical thickness measurements in female patients with bipolar I or II disorders (BD) versus healthy controls. Previous studies have only examined the thickness of the entire cortex, the GM. We developed a processing pipeline and a statistical tool for examining the ICM thickness between two groups. Results show that there are potential differences in GMm between BD and control groups. Further regional and statistical analysis is required to identify the regions of greatest difference, and to confirm significant differences between BD and control groups. / Thesis / Master of Science (MSc)

Background: Ayahuasca is a South American psychoactive brew that contains Dimethyltryptamine (DMT) and monoamine oxidase inhibitors (MAOIs). Research has experienced a resurgence of interest in exploring the potential of these substances in the last decade. Thus, the aim of this review was to systematically review studies that used a placebo-controlled design to explore the neural correlates and psychedelic experience induced by DMT and ayahuasca. Method: The search was conducted using the Web of Science and Scopus databases to select studies published between January 2000 and February 2022 that used neuroimaging techniques and recruited healthy participants. Thus, 7 papers were selected. Results: Ayahuasca alters electrical activity in the brain by decreasing spectralpower in all EEG frequency bands, predominantly in the alpha band. DMT caused a spatially widespread decrease in alpha bands and a more modest decrease in beta bands. Ayahuasca caused an increase in the flow of information in the brain from posterior regions to more frontal regions and an increase in scores in all the Hallucinogen Rating Scale (HRS) subscales. Ayahuasca decreased connectivity in the Default Mode Network (DMN) and increases connectivity between DMN and the salience network. Conclusion: Ayahuasca and DMT can reliably produce profound changes in perception, emotions, and sense of self. Moreover, the decrease in the alpha band, the alteration of information flow between posterior and frontal regions, and the decrease in connectivity in the DMN could be the keystone understanding the neural correlates and the psychedelic experience induced by DMT andayahuasca.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13554号 / 論医博第2283号 / 新制||医||1067(附属図書館) / (主査)教授 村井 俊哉, 教授 永井 洋士, 教授 井上 治久 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Schizophrenia (SCZ) is characterized by a disconnect from reality that manifests as various clinical and cognitive symptoms, as well as consistent neurobiological abnormalities. However, unique sex-related differences have been observed regarding clinical presentation that imply separate brain substrates. The present study characterized deep-brain morphology using shape features to understand whether the neurobiology of schizophrenia varies as a function of sex. This study analyzed multi-site archival data from 1,579 male (M) and 836 female (F) participants with SCZ, as well as 1,934 male and 1,828 female healthy controls (CON) from twenty-four cross-sectional study samples from the ENIGMA Schizophrenia Workgroup. Harmonized shape analysis protocols were applied to each site's data independently for bilateral caudate, putamen, globus pallidus, accumbens, amygdala, hippocampus, and thalamus obtained from T1-weighted structural MRI scans. Four separate contrasts were conducted: 1) Schizophrenia-Male/Control-Male; 2) Schizophrenia-Female/Control-Female; 3) Schizophrenia-Male/Schizophrenia-Female; 4) Control-Male/Control-Female. For contrasts 1 & 2, mass univariate meta-analyses revealed more-concave-than-convex shape differences for the hippocampus, amygdala, accumbens, and thalamus, with more-convex-than-concave differences in the putamen and pallidum (d = -0.30 to 0.30, SE = 0.03 to 0.10, p<0.05) in SCZ for both male and female group comparisons. More extensive patterns of deformation were noted in right hippocampus and right thalamus for SCZ women. Contrasts 3 & 4 revealed more-concave-than-convex shape differences in the thalamus, pallidum, putamen, and amygdala among females compared to males, with mixed findings in the hippocampus and caudate in both SCZ and CON contrasts (d = -0.30 to 0.20, SE = 0.03 to 0.09, p<0.05). Pattern and extent of deformation was greater in dorsal, ventral, and lateral aspects of putamen, thalamus, amygdala, and pallidum in SCZ. Findings are consistent with prior volume-based analyses in SCZ, as well as earlier studies on sex differences in the brain. Shape patterns reveal more extensive abnormalities in SCZ women relative to SCZ men that could aid in our understanding of clinical expression and treatment response differences between men and women.

Purpose: Arterial stiffening poses an increased risk of cerebrovascular diseases, cognitive impairments, and even dementia as cardiac pulsations reach further into the brain causing white matter hyperintensities and microbleeds. Therefore it is of interest to obtain methods to estimate and map cardiac related pulsatility in the brain. Improvements of functional magnetic resonance imaging (fMRI) sequences is potentially allowing detection of rapid physiological processes in the echo-planar imaging (EPI) signal in the brainthrough a higher sampling rate. Specifically in this thesis, estimation and localization of cardiac pulsation and respiration is conducted through analysis of resting state data obtained with a multiband EPI sequence that permits whole brain imaging at a shorter repetition time (TR) than conventional EPI. The origin of these physiological signals are likely a mixture of inflow and compartment volume shifts during the cardiac- and respiratory cycles. As the amount of physiologically related signal in the multiband sequence used at the Biomedical Engineering Dept. R&amp;D, Umeå University Hospital is unknown, the aim of this project is to find and map cardiac pulsatility and respiration for future research. Methods: Multiband fMRI data from 8 subjects was used, collected in a 3 Tesla scanner using a 32-channel head coil. The physiological signals were estimated through an algorithm that was developed to down-sample and temporally shift copies of simultaneous recordings of pulse and respiration. These signals were obtained using the scanner’s built-in pulse oximeter and a respiration belt. The shifted copies were voxel-wise, and slice by slice, correlated to the fMRI data using Pearson correlation. The time shift yielding maximum mean correlation within the brain was, for each slice, used to create statistical maps for significant voxels to show the localization and magnitude of correlation for cardiac pulsation andrespiration. Results: Many voxels around and nearby larger vessels and ventricles were highly correlated with the down-sampled, time shifted signals of the cardiac pulsation for all subjects. The cardiac pulsation maps resembled cerebral vasculature and were mostly localized around the Circle of Willis, brainstem, and the ventricles. Respiration signal was also highly correlated, and spatially located at the sides of the brain although mostly concentrated at the parietal- and occipital lobes. Conclusion: The results demonstrated that many voxels in the brain were highly correlated with cardiac pulsation and respiration using multiband EPI, and the statistical maps revealed distinct patterns for both of the physiological signals. This method and results for mapping cardiac related pulsatility, and respiration could be used for future research in order to better understand cerebral diseases and impairments, and alsoto improve fMRI filtering. Keywords: Arterial stiffness, Functional magnetic resonance imaging, Resting state, Multiband, CardiacPulsation, Respiration, Correlation analysis / Syfte: Arteriell förstyvning medför en ökad risk för cerebrovaskulära sjukdomar, kognitiva störningar och till och med demens då hjärtpulsationer når längre in i hjärnan orsakar vit materia hyperintensiteter och mikroblödningar. Av detta skäl är det därför av intresse att ta fram metoder för att estimera och kartlägga hjärtrelaterad pulsationer i hjärnan. Förbättringar av funktionella magnetresonanstomografi (fMRI) sekvenser kan möjliggöra detektering av snabba fysiologiska processer i den eko-planära (EPI) signalen i hjärnan genom en högre samplingsfrekvens. Specifikt i denna uppsats, utförs en skattning och lokalisering av hjärtpulsation och respiration genom analys av ’resting state’ data erhållet av en multiband-EPI sekvens som tillåter bildgivning av hela hjärnan med en kortare repetitionstid (TR) än konventionell EPI. Ursprunget avdessa fysiologiska signaler är sannolikt från en blandning av flöde- och volymsförändringar under hjärt- och respirationscyklerna. Då mängden av fysiologiskt relaterad signaler i multiband sekvensen, som används på Biomedicinska avdelningen, FoU Umeå Universitetssjukhust, är okänd så är målet med projektet att hitta och kartlägga hjärtpulsation och respiration för framtida forskning. Metod: Multiband fMRI data från 8 personer användes, insamlade från en 3 Tesla scanner med en 32-kanals huvudspole. De fysiologiska signalerna uppskattades genom en algoritm som utveckades för att sampla ned och tidsförskjuta kopior av simultant tagna signaler av puls och respiration. Dessa signaler samlades in med skannerns inbyggda pulsoximeter och andningsband. De förskjutna kopiorna var voxelvis, snitt för snitt, korrelerade med fMRI datat med användning av Pearson-korrelation. Det tidsskift somför varje snitt resulterade i maximal medelkorrelation i hjärnan användes för att skapa statistiska kartor, med endast signifikanta voxlar, för att visa var och hur mycket korrelation av hjärtpulsation och respiration som finns. Resultat: Många voxlar runt och nära större kärl och ventriklar var för alla personer starkt korrelerade medde samtidigt tagna, och tidsförskjutna signalerna av hjärtpulsation. Pulsationskartorna liknade cerebral vaskulatur och var mestadels lokaliserade kring Willis ring, hjärnstammen och ventriklar. Respirationssignalen var även starkt korrelerad och lokaliserad på sidorna av hjärnan, mestadels koncentrerat vid parietal- och occipital loberna. Slutsats: Resultaten visade att många voxlar i hjärnan var starkt korrelerade med hjärtpulsation och respiration vid användning av multiband EPI, och de statistiska kartorna avslöjade distinkta mönster för de båda fysiologiska signalerna. Den framtagna metoden och dess resultat för kartläggning av hjärtrelaterade pulsationer och respiration kan användas i framtida forskning i syfte att bättre förstå cerebrala sjukdomar och nedsättning, även för att förbättre fMRI filtrering. Nyckelord: Arteriell förstyvning, Funktionell magnetresonanstomografi, Resting state, Multiband, Hjärtpulsation, Andning, Korrelationsanalys

Background: The prevalence of adolescent obesity has increased drastically in the last few decades, spurring research examining causes and consequences of this chronic health condition. Neuroimaging techniques are being used to determine possible neural correlates of obesity that could help inform research in this field. However, the research among adolescents is not as abundant and findings so far are contradictory. This study sought to examine the association of the shape and volume of subcortical brain structures involved in reward processing with weight status in adolescent females. Additionally, this study sought to determine if the shape and volume of these structures were correlated with the Power of Food Scale (PFS), a self-report measure of food reward sensitivity. Method: The shape and volume of the nucleus accumbens (NAc) and amygdala were examined in 89 adolescent females ranging from normal weight to obese. MR scans were acquired using a high-resolution T1-weighted (MPRAGE) sequence. Shape was estimated using Large Deformation Diffeomorphic Metric Mapping. Seemingly unrelated regression models (SUM) were used for both brain structures with shape and volume as outcome variables and zBMI as the predictor variable. Pairwise correlation coefficients were determined for PFS score and both regions of interest (ROI). Results: SUM results revealed that zBMI was significantly associated with the shape of the left amygdala (β = -1.1, p<.021, 95% confidence interval [CI] = -2.02, -.16). When we controlled for age on the relationship between zBMI and left amygdala shape, we found the following partial correlation: r = -.24, p = .03. The PFS was found to have weak correlations with the volume and shape of the right NAc that approached significance (r = .20, p = .06; r = .19, p = .08, respectively). Conclusions: Our study suggests that there is an association between higher zBMI and aberrations in the shape of the left amygdala. We did not find associations between zBMI and the shape of our other reward-related ROIs, nor did we find any associations with zBMI and ROI volume. These findings suggest that variation in the shape of certain ROIs implicated in reward processing is associated with weight status in adolescents. Our findings also suggest that the shape and volume of the NAc could be a neural correlate of the PFS warranting further investigation. These findings may elucidate an important neural link between weight status and reward processing that could help to inform obesity research in adolescents.

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Shame is a self-conscious emotion that characterizes the life of all individuals. It arises when a moral violation occurs and the person is judged negatively by others for a way of being that does not correspond to the standards of society. Although over the years it has been widely treated from a theoretical point of view, there are few attempts in the literature to approach it scientifically by psychologists and neuroscientists. Using an integrated approach, based on neuroimaging, behavioral and neuropsychological investigations, in this thesis we aimed to investigate what are the cognitive mechanisms through which shame operates and what are its neural bases. After an initial theoretical introduction in which a novel model of shame functioning is proposed, two behavioral studies are presented in which an innovative experimental paradigm of shame elicitation has been validated and tested. Subsequently, the single-case of a patient with rare bilateral amygdala damage has been described. Since this region is notoriously crucial for emotional aspects, we tested the possibility that an amygdala injury could also lead to deficits in perception and recognition of shame. Afterward, to investigate if shame had its own specific neural activation map, a meta-analysis on functional studies in the literature that investigated the neural bases of shame and guilt (another self-conscious emotion) has been carried out. Finally, given the heterogeneity of the paradigms included in the meta-analysis, we run an fMRI study using our novel paradigm in order to detect shame neural signal. In general, by combining different methodologies, this work allowed us to approach shame from different perspectives, from simple elicitation and behavioral measurement to its neural basis. This has added a piece of knowledge in the field of affective neuroscience regarding a moral emotion (i.e. shame) that is fundamental to individual well-being within our society.