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Effects of Obesity and Weight Loss Following Bariatric Surgery on Brain Function, Structural Integrity and Metabolism
Get PDFObesity is one of the key challenges to health care system worldwide and its prevalence is estimated to rise to pandemic proportions. Numerous adverse health effects follow with increasing body weight, including increased risk of hypertension, diabetes, hypercholesterolemia, musculoskeletal pain and cancer. Current evidence suggests that obesity is associated with altered cerebral reward circuit functioning and decreased inhibitory control over appetitive food cues. Furthermore, obesity causes adverse shifts in metabolism and loss of structural integrity within the brain. Prior cross-sectional studies do not allow delineating which of these cerebral changes are recoverable after weight loss. We compared morbidly obese subjects with healthy controls to unravel brain changes associated with obesity. Bariatric surgery was used as an intervention to study which cerebral changes are recoverable after weight loss.
In Study I we employed functional magnetic resonance imaging (fMRI) to detect the brain basis of volitional appetite control and its alterations in obesity. In Studies II-III we used diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) to quantify the effects of obesity and the effects of weight loss on structural integrity of the brain. In study IV we used positron emission tomography (PET) with [18F]-FDG in fasting state and during euglycemic hyperinsulinemia to quantify effects of obesity and weight loss on brain glucose uptake.
The fMRI experiment revealed that a fronto-parietal network is involved in volitional appetite control. Obese subjects had lower medial frontal and dorsal striatal brain activity during cognitive appetite control and increased functional connectivity within the appetite control circuit. Obese subjects had initially lower grey matter and white matter densities than healthy controls in VBM analysis and loss of integrity in white matter tracts as measured by DTI. They also had initially elevated glucose metabolism under insulin stimulation but not in fasting state. After the weight loss following bariatric surgery, obese individuals’ brain volumes recovered and the insulin-induced increase in glucose metabolism was attenuated.
In conclusion, obesity is associated with altered brain function, coupled with loss of structural integrity and elevated glucose metabolism, which are likely signs of adverse health effects to the brain. These changes are reversed by weight loss after bariatric surgery, implicating that weight loss has a causal role on these adverse cerebral changes. Altogether these findings suggest that weight loss also promotes brain health.Key words: brain, obesity, bariatric surgery, appetite control, structural magnetic resonanceLihavuus yleistyy nopeasti koko maailmassa ja se on yksi suurimmista terveydenhuollon tulevaisuuden haasteista. Lihavuus lisää riskiä sairastua useisiin sairauksiin mm. verenpainetautiin, diabetekseen, tuki- ja liikuntaelinten sairauksiin ja useisiin syöpiin. Lihavilla on havaittu aivojen palkkiojärjestelmän reagoivan yliaktiivisesti ruokaan liittyviin ärsykkeisiin ja toisaalta ruokahalua hillitsevien alueiden toiminnan on havaittu olevan heikompaa kuin normaalipainoisilla. Lihavuus aiheuttaa myös haitallisia muutoksia aivosolujen rakenteessa ja aineenvaihdunnassa. Näiden muutosten palautumispotentiaalia ei voida arvioida poikkileikkaustutkimuksissa. Tässä työssä tutkimme sairaalloisen lihavia lihavuusleikkaukseen valittuja potilaita, joiden aivokuvantamistuloksia verrattiin normaalipainoisten vastaaviin kuvauksiin. Potilaat tutkittiin myös kuusi kuukautta lihavuusleikkauksen jälkeen painonlaskun aiheuttamien aivomuutosten tutkimiseksi.
Ensimmäisessä tutkimuksessa ruokahalun säätelyjärjestelmän toiminnan ja lihavuuden aiheuttamien muutosten selvittämiseksi käytettiin toiminnallista magneettikuvantamista (fMRI). Rakenteellisia muutoksia arvioitiin II ja III osatyössä diffuusiotensorikuvantamisella (DTI) sekä vokseliperustaisen morfometrian avulla (VBM). Neljännessä osatyössä aivojen sokeriaineenvaihduntaa tutkittiin positroniemissiotomografian (PET) avulla käyttämällä [18F]-FDG-merkkiainetta paastotilassa ja insuliini-stimulaation aikana. VBM -ja PET-menetelmiä käytettiin myös lihavuusl eikkauksen vaikutusten arviointiin.
fMRI-kokeessa havaittiin, että ruokahalun säätelyyn osallistuu laaja hermoverkko jonka keskeiset osat sijoittuvat otsa- ja päälaenlohkoihin. Lihavilla tutkittavilla havaittiin alentuneet vasteet häntätumakkeessa ja etupihtipoimun alueella. Lisäksi heillä havaittiin voimakkaammat toiminnalliset yhteydet ruokahalun säätelyverkostossa. Lihavuus aiheuttaa aivoissa laajaa aivokudoksen harventumaa ja hermoratojen eheyden alentumaa. PET-tutkimuksessa havaittiin lihavuuden lisäävän aivojen insuliiniherkkyyttä. Puoli vuotta lihavuusleikkauksen jälkeen rakenteelliset ja aineenvaihdunnan muutokset palautuivat osittain.Siirretty Doriastaei tietoa saavutettavuudest
Associations of Leukocyte Telomere Length with Trait Resilience, ACEs, and Psychological Distress among Expecting Parents in the FinnBrain Birth Cohort
No full textBackground: Telomere attrition has previously been associated with mental health problems and adverse
childhood experiences (ACEs). Resilience has been shown to protect against mental health problems even in
the context of ACEs. This study examined the associations between leukocyte telomere length (LTL),
symptoms of psychological distress, ACEs, and trait resilience. We examined whether LTL mediates the
negative effects of ACEs and whether trait resilience moderates the association between LTL and distress.
Methods: The study population was drawn from the ongoing FinnBrain Birth Cohort Study and included 342
mothers and 339 fathers who had provided blood samples and questionnaire data during pregnancy.
Questionnaire data included Connor-Davidson Resilience Scale 10, Edinburgh Postnatal Depression Scale,
Symptom Checklist, and Trauma Distress Scale. Data analysis included regression analysis, mixed methods
models and statistical evaluation.
Results: ACEs were associated with depressive and anxiety symptoms. However, contrary to the initial
hypothesis, LTL was not associated with ACEs or distress symptoms, and thus did not mediate their
association. Furthermore, resilience was not associated with LTL and did not moderate the possible
association between LTL and distress symptoms.
Conclusions: The study found no association between telomere length and ACEs, psychological distress, or
trait resilience. The mild distress symptoms, limited exposure to high ACEs, and the predominantly
moderate to high socioeconomic status in the sample may be relevant to interpreting these findings.
Encouragingly, not all adverse childhood experiences may necessarily lead to telomere attrition.We would like to warmly thank all FinnBrain families that participated in the study.
This research was funded by Juho Vainio Foundation (V.M; E-L.K; J.T), Finnish Brain Foundation (V.M), Turku
University Foundation (V.M.;E-L.K.; J.T.), Academy of Finland (#253270, H.K; #346790, E-L.K.), Signe and Ane
Gyllenberg Foundation (E-L.K; H.K.;L.K.), Finnish State Grants for Clinical Research (E-L.K.; H.K; L.K.; J.T.),
Research Foundation Flanders (FWO grant 12X9623N, D.M.), Strategic Research Council (SRC) established
within the Research Council of Finland (#352648, #352655, L.K.), Finnish Medical Association (L.K.; J.T.),
Sigrid Jusélius Foundation (J.T.), Emil Aaltonen Foundation (J.T.), Alfred Kordelin Foundation (J.T.), Alfred
Kordelin Foundatio (J.T.), Orion Research Foundation (J.T.)
Authorship contribution statement: V.M.: conceptualization, methodology, statistical analysis, investigation,
review & editing; H.K.: founding acquisition, conceptualization, methodology, supervision; L.P.:
methodology, statistical analysis; T.P.: telomere analysis, review & editing; E.V.: conceptualization,
methodology, review & editing; D.M.: telomere analysis, review & editing; L.K.: founding acquisition,
conceptualization, methodology, review & editing; J.T.: review & editing; E-K.K.: conceptualization,
methodology, founding acquisition, supervision, review & editing. All authors contributed to the writing of
the final manuscript.
The data that support the findings of this study are available through collaboration but not freely accessible
due to Finnish legislation
Infants' sex affects neural responses to affective touch in early infancy
Get PDFSocial touch is closely related to the establishment and maintenance of social bonds in humans, and the sensory brain circuit for gentle brushing is already active soon after birth. Brain development is known to be sexually dimorphic, but the potential effect of sex on brain activation to gentle touch remains unknown. Here, we examined brain activation to gentle skin stroking, a tactile stimulation that resembles affective or social touch, in term-born neonates. Eighteen infants aged 11–36 days, recruited from the FinnBrain Birth Cohort Study, were included in the study. During natural sleep, soft brush strokes were applied to the skin of the right leg during functional magnetic resonance imaging (fMRI) at 3 cm/s velocity. We examined potential differ- ences in brain activation between males (n = 10) and females (n = 8) and found that females had larger blood oxygenation level dependent (BOLD) responses (brushing vs. rest) in bilateral orbitofrontal cortex (OFC), right ventral striatum and bilateral inferior striatum, pons, and cerebellum compared to males. Moreover, the psychophysiologi- cal interactions (PPI) analysis, setting the left and right OFC as seed regions, revealed significant differences between males and females. Females exhibited stronger PPI connectivity between the left OFC and posterior cingulate or cuneus. Our work sug- gests that social touch neural responses are different in male and female neonates, which may have major ramifications for later brain, cognitive, and social development. Finally, many of the sexually dimorphic brain responses were subcortical, not captured by surface-based neuroimaging, indicating that fMRI will be a relevant technique for future studies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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