9 research outputs found
Renal Sinus Fat Is Expanded in Patients with Obesity and/or Hypertension and Reduced by Bariatric Surgery Associated with Hypertension Remission
Renal sinus fat is a fat depot at the renal hilum. Because of its location around the renal artery, vein, and lymphatic vessels, an expanded renal sinus fat mass may have hemodynamic and renal implications. We studied whether renal sinus fat area (RSF) associates with hypertension and whether following bariatric surgery a decrease in RSF associates with improvement of hypertension. A total of 74 severely obese and 46 lean controls were studied with whole-body magnetic resonance imaging (MRI). A total of 42 obese subjects were re-studied six months after bariatric surgery. RSF was assessed by two independent researchers using sliceOmatic. Glomerular filtration rate (eGFR) was estimated according to the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration). Patients with obesity accumulated more RSF compared to lean controls (2.3 [1.7-3.1] vs. 1.8 [1.4-2.5] cm(2), p = 0.03). Patients with hypertension (N = 36) had a larger RSF depot compared to normotensive subjects (2.6 [2.0-3.3] vs. 2.0 [1.4-2.5] cm(2), p = 0.0007) also after accounting for body mass index (BMI). In the pooled data, RSF was negatively associated with eGFR (r = -0.20, p = 0.03), whereas there was no association with systolic or diastolic blood pressure. Following bariatric surgery, RSF was reduced (1.6 [1.3-2.3] vs. 2.3 [1.7-3.1] cm(2), p = 0.03) along with other markers of adiposity. A total of 9/27 of patients achieved remission from hypertension. The remission was associated with a larger decrease in RSF, compared to patients who remained hypertensive (-0.68 [ -0.74 to -0.44] vs. -0.28 [ -0.59 to 0] cm(2), p = 0.009). The accumulation of RSF seems to be involved in the pathogenesis of hypertension in obesity. Following bariatric surgery, loss of RSF was associated with remission from hypertension
Comparison of: (2S,4R)-4-[F-18]Fluoroglutamine, [C-11]Methionine, and 2-Deoxy-2-[F-18]Fluoro-D-Glucose and Two Small-Animal PET/CT Systems Imaging Rat Gliomas
Purpose: The three positron emission tomography (PET) imaging compounds: (2S,4R)-4-[F-18]Fluoroglutamine ([F-18]FGln), L-[methyl-C-11]Methionine ([C-11]Met), and 2-deoxy-2-[F-18]fluoro-D-glucose ([F-18]FDG) were investigated to contrast their ability to image orthotopic BT4C gliomas in BDIX rats. Two separate small animal imaging systems were compared for their tumor detection potential. Dynamic acquisition of [F-18]FGln was evaluated with multiple pharmacokinetic models for future quantitative comparison.Procedures: Up to four imaging studies were performed on each orthotopically grafted BT4C glioma-bearing BDIX rat subject (n = 16) on four consecutive days. First, a DOTAREM(R) contrast enhanced MRI followed by attenuation correction CT and dynamic PET imaging with each radiopharmaceutical (20 min [C-11]Met, 60 min [F-18]FDG, and 60 min [F-18]FGln with either the Molecubes PET/CT (n = 5) or Inveon PET/CT cameras (n = 11). Ex vivo brain autoradiography was completed for each radiopharmaceutical and [F-18]FGln pharmacokinetics were studied by injecting 40 MBq into healthy BDIX rats (n = 10) and collecting blood samples between 5 and 60 min. Erythrocyte uptake, plasma protein binding and plasma parent-fraction were combined to estimate the total blood bioavailability of [F-18]FGln over time. The corrected PET-image blood data was then applied to multiple pharmacokinetic models.Results: Average BT4C tumor-to-healthy brain tissue uptake ratios (TBR) for PET images reached maxima of: [F-18]FGln TBR: 1.99 +/- 0.19 (n = 13), [F-18]FDG TBR: 1.41 +/- 0.11 (n = 6), and [C-11]Met TBR: 1.08 +/- 0.08, (n = 12) for the dynamic PET images. Pharmacokinetic modeling in dynamic [F-18]FGln studies suggested both reversible and irreversible uptake play a similar role. Imaging with Inveon and Molecubes yielded similar end-result ratios with insignificant differences (p > 0.25).Conclusions: In orthotopic BT4C gliomas, [F-18]FGln may offer improved imaging versus [C-11]Met and [F-18]FDG. No significant difference in normalized end-result data was found between the Inveon and Molecubes camera systems. Kinetic modelling of [F-18]FGln uptake suggests that both reversible and irreversible uptake play an important role in BDIX rat pharmacokinetics.</p
Aberrant motor contagion of emotions in psychopathy and high-functioning autism
Psychopathy and autism are both associated with aberrant social skills and empathy, yet only psychopaths are markedly antisocial and violent. Here, we compared the functional neural alterations underlying these two groups that both have aberrant empathetic abilities but distinct behavioral phenotypes. We studied 19 incarcerated male offenders with high psychopathic traits, 20 males with high-functioning autism, and 19 age-matched healthy controls. All groups underwent functional magnetic resonance imaging while they viewed dynamic happy, angry, and disgusted faces or listened to laughter and crying sounds. Psychopathy was associated with reduced somatomotor responses to almost all expressions, while participants with autism demonstrated less marked and emotion-specific alterations in the somatomotor area. These data suggest that psychopathy and autism involve both common and distinct functional alterations in the brain networks involved in the socioemotional processing. The alterations are more profound in psychopathy, possibly reflecting the more severely disturbed socioemotional brain networks in this population
Improving fMRI data coherence analysis method for researching semantic priming
Toiminnallinen magneettikuvaus (fMRI) kartoittaa ihmisaivojen eri kognitiivisiin toi-mintoihin käyttäviä alueita. Analysoidun datan perusteella päätellään aivoista tehtävään osallistuva alue, jota verrataan jo aiemmin tunnistettuihin alueisiin, Broadmanin alueet lienevät tunnetuimmat. Aivoalueita tunnetaan jo kattavasti.
Tehtäviin osallistuvien aivoalueiden välistä vuorovaikutusta ei kuitenkaan tunneta yhtä hyvin. Kaksi tehtävän aktivoimaa aluetta saattaa olla yhteydessä toisiinsa joko suoraan tai kolmannen, ehkä useammankin aivoalueen välityksellä. Tutkimusmenetelmäkään yhteyksien analysoimiseksi ei ole vakiintunut. Otaniemen Aivotutkimusyksikössä O.V. Lounasmaa -laboratoriossa kehitetään erästä koherenssiin perustuvaa yhteysanalyysi-menetelmää, jonka käyttämisen tietotaito katosi kehittäjän lähdettyä laboratoriosta.
Tämän työn tarkoituksena on tuoda koherenssiin perustuvan yhteysanalyysimenetelmän tietotaito laboratorion käyttöön uudelleen. Matlabilla koodatut yhteysanalyysimenetel-män koodit etsitään ja niiden käyttö opetellaan uudelleen. Koodit järjestetään loogiseksi kokonaisuudeksi, kommentoidaan yksityiskohtaisesti ja sisältö muokataan helppokäyt-töiseksi. Jatkokehityksenä koherenssianalyysimenetelmää kehitetään neljällä lisäyksellä ja optimoinnilla, jotka vähentävät mitatun datan häiriötä merkittävästi, helpottavat pa-rametrien arvojen määrittämistä ja vähentävät noin 80 %:a ketjun läpilaskuaikaa. Lisäksi tämä työ kirjoitetaan hyvin yksityiskohtaisesti ketjun dokumentoinniksi.
Kehitystyötä ja kehitetyllä menetelmällä analysointia varten laboratoriosta annetaan analysoimatta jäänyt semanttista virittämistä tutkiva fMRI-data. Semanttinen virittämi-nen on ilmiö, joka syntyy aivojen käsitellessä merkityksellisesti eli semanttisesti toisiinsa liittyviä sanoja: semanttisesti toisiinsa liittyvien sanojen prosessointi on liittymättömiä sanoja nopeampaa. Klassisesti semanttista virittymistä tutkitaan sana- tai kuvaparien avulla, mutta tässä kokeessa koehenkilöt lukevat neljän sanan semanttisesti toisiinsa liittyviä ja liittymättömiä substantiivisanalistoja.
Data esikäsitellään ja aktivaatioanalyysillä osoitetaan soveltuvuus yhteysanalyysiä var-ten. Yhteydet lasketaan sekä koko pään kattavasti noin 1800 solmupisteen välillä että 77 AAL-parsellaatiota (Automated Anatomical Labeling) vastaavien alueiden välillä. Tu-lokset osoittavat koko aivojen, myös oikean aivopuoliskon, osallistuvan kielellisen in-formaation käsittelemiseen
Dissociable neural systems for unconditioned acute and sustained fear
Fear protects organisms by increasing vigilance and preparedness, and by coordinating survival responses during life-threatening encounters. The fear circuit must thus operate on multiple timescales ranging from preparatory sustained alertness to acute fight-or-flight responses. Here we studied the brain basis of sustained and acute fear using naturalistic functional magnetic resonance imaging (fMRI) enabling analysis of different time-scales of fear responses. Subjects (N = 37) watched feature-length horror movies while their hemodynamic brain activity was measured with fMRI. Time-variable intersubject correlation (ISC) was used to quantify the reliability of brain activity across participants, and seed-based phase synchronization was used for characterizing dynamic connectivity. Subjective ratings of fear were used to assess how synchronization and functional connectivity varied with emotional intensity. These data suggest that acute and sustained fear are supported by distinct neural pathways, with sustained fear amplifying mainly sensory responses, and acute fear increasing activity in brainstem, thalamus, amygdala and cingulate cortices. Sustained fear increased ISC in regions associated with acute fear, and also amplified functional connectivity within this network. The results were replicated in an independent experiment with a different subject sample and stimulus movie. The functional interplay between cortical networks involved in sustained anticipation of, and acute response to, threat involves a complex and dynamic interaction that depends on the proximity of threat, and the need to employ threat appraisals and vigilance for decision making and response selection.Peer reviewe
Opioidergic regulation of emotional arousal: A combined PET–fMRI study
Emotions can be characterized by dimensions of arousal and valence (pleasantness). While the functional brain bases of emotional arousal and valence have been actively investigated, the neuromolecular underpinnings remain poorly understood. We tested whether the opioid and dopamine systems involved in reward and motivational processes would be associated with emotional arousal and valence. We used in vivo positron emission tomography to quantify μ-opioid receptor and type 2 dopamine receptor (MOR and D2R, respectively) availability in brains of 35 healthy adult females. During subsequent functional magnetic resonance imaging carried out to monitor hemodynamic activity, the subjects viewed movie scenes of varying emotional content. Arousal and valence were associated with hemodynamic activity in brain regions involved in emotional processing, including amygdala, thalamus, and superior temporal sulcus. Cerebral MOR availability correlated negatively with the hemodynamic responses to arousing scenes in amygdala,hippocampus,thalamus, and hypothalamus, whereas no positive correlations were observed in any brain region. D2R availability—here reliably quantified only in striatum—was not associated with either arousal or valence. These results suggest that emotional arousal is regulated by the MOR system, and that cerebral MOR availability influences brain activity elicited by arousing stimuli.Peer reviewe
Decoding music-evoked emotions in the auditory and motor cortex
Music can induce strong subjective experience of emotions, but it is debated whether these responses engage the same neural circuits as emotions elicited by biologically significant events. We examined the functional neural basis of music-induced emotions in a large sample (n = 102) of subjects who listened to emotionally engaging (happy, sad, fearful, and tender) pieces of instrumental music while their haemodynamic brain activity was measured with functional magnetic resonance imaging (fMRI). Ratings of the four categorical emotions and liking were used to predict haemodynamic responses in general linear model (GLM) analysis of the fMRI data. Multivariate pattern analysis (MVPA) was used to reveal discrete neural signatures of the four categories of music-induced emotions. To map neural circuits governing non-musical emotions, the subjects were scanned while viewing short emotionally evocative film clips. The GLM revealed that most emotions were associated with activity in the auditory, somatosensory and motor cortices, cingulate gyrus, insula, and precuneus. Fear and liking also engaged the amygdala. In contrast, the film clips strongly activated limbic and cortical regions implicated in emotional processing. MVPA revealed that activity in the auditory cortex in particular as well as in the primary motor cortices reliably discriminated the emotion categories. Our results indicate that different music-induced emotions have distinct representations in regions supporting auditory processing, motor control, somatosensation and interoception but do not strongly rely on limbic and medial prefrontal regions critical for emotions with survival value
Functional organization of social perception networks in the human brain
Humans rapidly extract diverse and complex information from ongoing social interactions, but the perceptual and neural organization of the different aspects of social perception remains unresolved. We showed short movie clips with rich social content to 97 healthy participants while their haemodynamic brain activity was measured with fMRI. The clips were annotated moment-to-moment for a large set of social features and 45 of the features were evaluated reliably between annotators. Cluster analysis of the social features revealed that 13 dimensions were sufficient for describing the social perceptual space. Three different analysis methods were used to map the social perceptual processes in the human brain. Regression analysis mapped regional neural response profiles for different social dimensions. Multivariate pattern analysis then established the spatial specificity of the responses and intersubject correlation analysis connected social perceptual processing with neural synchronization. The results revealed a gradient in the processing of social information in the brain. Posterior temporal and occipital regions were broadly tuned to most social dimensions and the classifier revealed that these responses showed spatial specificity for social dimensions; in contrast Heschl gyri and parietal areas were also broadly associated with different social signals, yet the spatial patterns of responses did not differentiate social dimensions. Frontal and subcortical regions responded only to a limited number of social dimensions and the spatial response patterns did not differentiate social dimension. Altogether these results highlight the distributed nature of social processing in the brain