| 1. |
- Ahs, Fredrik, et al.
(författare)
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High-frequency heart rate variability and cortico-striatal activity in men and women with social phobia
- 2009
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 47:3, s. 815-820
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Tidskriftsartikel (refereegranskat)abstract
- Identifying brain systems that regulate or modulate autonomic nervous system functions may identify pathways through which psychosocial factors can influence health and disease. Reduced high-frequency heart rate variability (HF-HRV) characterizes anxiety disordered patients and is predictive of adverse myocardial events. Sex differences in the prevalence of anxiety disorders and cardiac diseases implicate the possibility of sex specific neural regulation of HF-HRV. We investigated the correlation between HF-HRV and regional cerebral blood flow (rCBF) in 28 subjects (15 women) with social phobia undergoing a stressful public speaking task. Regional CBF was measured with [(15)O] water positron emission tomography. Stress induced rCBF correlated positively with HF-HRV in the right supra genual anterior cingulate cortex Brodmann's area (BA) 32, the right head of the caudate nucleus and bilaterally in the medial prefrontal cortex (BA10), extending into the dorsolateral prefrontal cortex (BA46) in the left hemisphere. Men showed larger positive co-variation in the caudate than women. These findings underscore the importance of the emotional division of the anterior cingulate cortex, the prefrontal cortex and the striatum in cardiovagal activity. The study replicates and extends results from published functional neuroimaging studies on cardioregulatory or modulatory areas in healthy subjects to men and women with social phobia. Moreover, caudate functions, possibly related to dopaminergic neurotransmission, have sexually dimorphic effects on vagal modulation of the heart.
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| 2. |
- Brooks, Samantha J., et al.
(författare)
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Exposure to subliminal arousing stimuli induces robust activation in the amygdala, hippocampus, anterior cingulate, insular cortex and primary visual cortex : A systematic meta-analysis of fMRI studies
- 2012
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 59:3, s. 2962-2973
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Forskningsöversikt (refereegranskat)abstract
- Functional Magnetic Resonance Imaging (fMRI) demonstrates that the subliminal presentation of arousing stimuli can activate subcortical brain regions independently of consciousness-generating top-down cortical modulation loops. Delineating these processes may elucidate mechanisms for arousal, aberration in which may underlie some psychiatric conditions. Here we are the first to review and discuss four Activation Likelihood Estimation (ALE) meta-analyses of fMRI studies using subliminal paradigms. We find a maximum of 9 out of 12 studies using subliminal presentation of faces contributing to activation of the amygdala, and also a significantly high number of studies reporting activation in the bilateral anterior cingulate, bilateral insular cortex, hippocampus and primary visual cortex. Subliminal faces are the strongest modality, whereas lexical stimuli are the weakest. Meta-analyses independent of studies using Regions of Interest (ROI) revealed no biasing effect Core neuronal arousal in the brain, which may be at first independent of conscious processing, potentially involves a network incorporating primary visual areas, somatosensory, implicit memory and conflict monitoring regions. These data could provide candidate brain regions for the study of psychiatric disorders associated with aberrant automatic emotional processing.
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| 3. |
- Cervenka, Simon, et al.
(författare)
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Association between striatal and extrastriatal dopamine D2-receptor binding and social desirability
- 2010
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Ingår i: NeuroImage. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1053-8119 .- 1095-9572. ; 50:1, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- Research on the biological underpinnings of personality can provide leads to the pathophysiology of psychiatric disorders. In particular, interpersonal aspects of behavior are a common problem during the course of psychiatric illness. Animal research has demonstrated a role for the dopamine system in social behaviour, and recent molecular imaging studies have shown a negative correlation between dopamine D2-receptor binding in the striatum and social desirability. The emotional and cognitive aspects of social behavior suggest involvement of brain regions outside of the striatum, such as limbic structures. The aim of the present study was to explore associations between the personality trait social desirability and dopamine D2-receptor binding in both striatal and extrastriatal brain regions. We examined 16 control subjects with Positron Emission Tomography and the radioligands [C-11]raclopride and [C-11]FLB 457, in relation to social desirability in the inventory Swedish universities Scales of Personality. [C-11]raclopride D2-receptor binding in the striatum showed negative correlations to social desirability scores, corroborating previous findings. Furthermore, a correlation of a higher statistical significance was demonstrated for [C-11]FLB 457 binding in the hippocampal-amygdala complex. A separate analysis of social desirability items in relation to a model of interpersonal behaviour revealed that the associations were driven by items reflecting high submissiveness and high affiliation. Taken together with previous evidence on D2-receptor binding and social behaviour, a role for dopaminergic neurotransmission in regulating displays of dominance vs. submissive behaviour is proposed. (C) 2009 Elsevier B.V. All rights reserved.
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| 4. |
- Cervenka, Simon, et al.
(författare)
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Associations between dopamine D2-receptor binding and cognitive performance indicate functional compartmentalization of the human striatum
- 2008
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Ingår i: NeuroImage. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1053-8119 .- 1095-9572. ; 40:3, s. 1287-1295
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Tidskriftsartikel (refereegranskat)abstract
- Based on pharmacological, neuroanatomical, and lesion studies in animals, a functional compartmentalization of the striatal complex has been proposed. However, this has not been convincingly demonstrated in human subjects. Most functions ascribed to the striatum have been linked to its dense dopaminergic innervation, from motor control to higher-order brain functions ( e. g., cognition), making the dopamine system a suitable probe for striatal function. Limbic striatum, a region involved in reward processing, has recently been implicated also in episodic memory function. Here we examined striatal dopamine D2-receptor binding in 16 healthy subjects using PET and the radioligand [C-11] raclopride, in relation to cognitive performance. Receptor availability in limbic striatum was related to performance in tests of episodic memory, but not to tests of verbal fluency and general knowledge. By contrast, D2 binding in associative and sensorimotor striatum was less strongly related to episodic memory, but showed associations to the non-episodic tasks. These findings provide biochemical evidence for a functional compartmentalization of human striatum, and serve as a starting point for a more detailed investigation of striatal biomarkers in the normal brain as well as in neurodegenerative disorders. (c) 2008 Elsevier Inc. All rights reserved.
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| 5. |
- de Manzano, Orjan, et al.
(författare)
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Individual differences in the proneness to have flow experiences are linked to dopamine D2-receptor availability in the dorsal striatum
- 2013
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Ingår i: NeuroImage. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1053-8119 .- 1095-9572. ; 67, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Flow is a subjective experience of high but effortless attention, enjoyment, and low self-awareness that can occur during the active performance of challenging tasks. The dispositional proneness to experience flow is associated with personality traits that are known to be influenced by dopaminergic neural systems. Here, for the first time, we investigated relations between flow proneness and dopaminergic function. Specifically, we tested the hypothesis that the availability of dopamine D2-receptors in the striatum is positively associated with flow proneness. Striatal D2-receptor availability was measured in a sample of 25 healthy adults using positron emission tomography and [C-11]raclopride. Flow proneness was measured using the Swedish Flow Proneness Questionnaire. As hypothesized, there was a significant correlation (r = .41) between striatal D2-receptor availability and flow proneness. An exploratory analysis of striatal subregions showed that the relation was mainly driven by the dorsal striatum, with a significantly higher correlation in the putamen than in the ventral striatum. The findings constitute the first demonstration of an association between flow proneness and dopaminergic function. We suggest that the proneness to experience flow is related to personality dimensions that are under dopaminergic control and characterized by low impulsiveness, stable emotion, and positive affect. (C) 2012 Elsevier Inc. All rights reserved.
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| 6. |
- Emmert, Kirsten, et al.
(författare)
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Meta-analysis of real-time fMRI neurofeedback studies using individual participant data : How is brain regulation mediated?
- 2016
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 124:Part A, s. 806-812
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Tidskriftsartikel (refereegranskat)abstract
- An increasing number of studies using real-time fMRI neurofeedback have demonstrated that successful regulation of neural activity is possible in various brain regions. Since these studies focused on the regulated region(s), little is known about the target-independent mechanisms associated with neurofeedback-guided control of brain activation, i.e. the regulating network. While the specificity of the activation during self-regulation is an important factor, no study has effectively determined the network involved in self-regulation in general. In an effort to detect regions that are responsible for the act of brain regulation, we performed a post-hoc analysis of data involving different target regions based on studies from different research groups. We included twelve suitable studies that examined nine different target regions amounting to a total of 175 subjects and 899 neurofeedback runs. Data analysis included a standard first-(single subject, extracting main paradigm) and second-level (single subject, all runs) general linear model (GLM) analysis of all participants taking into account the individual timing. Subsequently, at the third level, a random effects model GLM included all subjects of all studies, resulting in an overall mixed effects model. Since four of the twelve studies had a reduced field of view (FoV), we repeated the same analysis in a subsample of eight studies that had a well-overlapping FoV to obtain a more global picture of self-regulation. The GLM analysis revealed that the anterior insula as well as the basal ganglia, notably the striatum, were consistently active during the regulation of brain activation across the studies. The anterior insula has been implicated in interoceptive awareness of the body and cognitive control. Basal ganglia are involved in procedural learning, visuomotor integration and other higher cognitive processes including motivation. The larger FoV analysis yielded additional activations in the anterior cingulate cortex, the dorsolateral and ventrolateral prefrontal cortex, the temporo-parietal area and the visual association areas including the temporo-occipital junction. In conclusion, we demonstrate that several key regions, such as the anterior insula and the basal ganglia, are consistently activated during self-regulation in real-time fMRI neurofeedback independent of the targeted region-ofinterest. Our results imply that if the real-time fMRI neurofeedback studies target regions of this regulation network, such as the anterior insula, care should be given whether activation changes are related to successful regulation, or related to the regulation process per se. Furthermore, future research is needed to determine how activation within this regulation network is related to neurofeedback success.
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| 7. |
- Fang, Xiaotian T., et al.
(författare)
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High detection sensitivity with antibody-based PET radioligand for amyloid beta in brain
- 2019
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 184, s. 881-888
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Tidskriftsartikel (refereegranskat)abstract
- PET imaging of amyloid-beta (A beta) deposits in brain has become an important aid in Alzheimer's disease diagnosis, and an inclusion criterion for patient enrolment into clinical trials of new anti-A beta treatments. Available PET radioligands visualizing A beta bind to insoluble fibrils, i.e. A beta plaques. Levels of prefibrillar A beta forms, e.g. soluble oligomers and protofibrils, correlate better than plaques with disease severity and these soluble species are the neurotoxic form of A beta leading to neurodegeneration. The goal was to create an antibody-based radioligand, recognizing not only fibrillary A beta , but also smaller and still soluble aggregates. We designed and expressed a small recombinant bispecific antibody construct, di-scFv 3D6-8D3, targeting the A beta N-terminus and the transferrin receptor (TfR). Natively expressed at the blood-brain barrier (BBB), TfR could thus be used as a brain-blood shuttle. Di-scFv 3D6-8D3 bound to A beta 1-40 with high affinity and to TfR with moderate affinity. Di-scFv [I-124] 3D6-8D3 was injected in two transgenic mouse models overexpressing human A beta and wild-type control mice and PET scanned at 14, 24 or 72 h after injection. Di-scFv [I-124] 3D6-8D3 was retained in brain of transgenic animals while it was cleared from wild-type lacking A beta . This difference was observed from 24 h onwards, and at 72 h, 18 months old transgenic animals, with high load of A beta pathology, displayed SUVR of 2.2-3.5 in brain while wildtype showed ratios close to unity. A subset of the mice were also scanned with [C-11] PIB. Again wt mice displayed ratios of unity while transgenes showed slightly, non-significantly, elevated SUVR of 1.2, indicating improved sensitivity with novel di-scFv [I-124] 3D6-8D3 compared with [C-11] PIB. Brain concentrations of di-scFv [I-124] 3D6-8D3 correlated with soluble A beta (p < 0.0001) but not with total A beta, i.e. plaque load (p = 0.34). We have successfully created a small bispecific antibody-based radioligand capable of crossing the BBB, subsequently binding to and visualizing intrabrain A beta in vivo. The radioligand displayed better sensitivity compared with [C-11] PIB, and brain concentrations correlated with soluble neurotoxic A beta aggregates.
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| 8. |
- Flodin, P., et al.
(författare)
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Normalization of aberrant resting state functional connectivity in fibromyalgia patients following a three month physical exercise therapy
- 2015
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Ingår i: NeuroImage. - : Elsevier Inc.. - 1053-8119 .- 1095-9572. ; 9, s. 134-139
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Tidskriftsartikel (refereegranskat)abstract
- Physical exercise is one of the most efficient interventions to mitigate chronic pain symptoms in fibromyalgia (FM). However, little is known about the neurophysiological mechanisms mediating these effects. In this study we investigated resting-state connectivity using functional magnetic resonance imaging (fMRI) before and after a 15 week standardized exercise program supervised by physical therapists. Our aim was to gain an understanding of how physical exercise influences previously shown aberrant patterns of intrinsic brain activity in FM. Fourteen FM patients and eleven healthy controls successfully completed the physical exercise treatment. We investigated post- versus pre-treatment changes of brain connectivity, as well as changes in clinical symptoms in the patient group. FM patients reported improvements in symptom severity. Although several brain regions showed a treatment-related change in connectivity, only the connectivity between the right anterior insula and the left primary sensorimotor area was significantly more affected by the physical exercise among the fibromyalgia patients compared to healthy controls. Our results suggest that previously observed aberrant intrinsic brain connectivity patterns in FM are partly normalized by the physical exercise therapy. However, none of the observed normalizations in intrinsic brain connectivity were significantly correlated with symptom changes. Further studies conducted in larger cohorts are warranted to investigate the precise relationship between improvements in fibromyalgia symptoms and changes in intrinsic brain activity. © 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license.
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| 9. |
- Freiburghaus, Tove, et al.
(författare)
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Low convergent validity of [11C]raclopride binding in extrastriatal brain regions : A PET study of within-subject correlations with [11C]FLB 457
- 2021
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 226
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Tidskriftsartikel (refereegranskat)abstract
- Dopamine D2 receptors (D2-R) in extrastriatal brain regions are of high interest for research in a wide range of psychiatric and neurologic disorders. Pharmacological competition studies and test-retest experiments have shown high validity and reliability of the positron emission tomography (PET) radioligand [11C]FLB 457 for D2-R quantification in extrastriatal brain regions. However, this radioligand is not available at most research centers. Instead, the medium affinity radioligand [11C]raclopride, which has been extensively validated for quantification of D2-R in the high-density region striatum, has been applied also in studies on extrastriatal D2-R. Recently, the validity of this approach has been questioned by observations of low occupancy of [11C]raclopride in extrastriatal regions in a pharmacological competition study with quetiapine. Here, we utilise a data set of 16 healthy control subjects examined with both [11C]raclopride and [11C]FLB 457 to assess the correlation in binding potential (BPND) in extrastriatal brain regions. BPND was quantified using the simplified reference tissue model with cerebellum as reference region. The rank order of mean regional BPND values were similar for both radioligands, and corresponded to previously reported data, both post-mortem and using PET. Nevertheless, weak to moderate within-subject correlations were observed between [11C]raclopride and [11C]FLB 457 BPND extrastriatally (Pearson's R: 0.30-0.56), in contrast to very strong correlations between repeated [11C]FLB 457 measurements (Pearson's R: 0.82-0.98). In comparison, correlations between repeated [11C]raclopride measurements were low to moderate (Pearson's R: 0.28-0.75). These results are likely related to low signal to noise ratio of [11C]raclopride in extrastriatal brain regions, and further strengthen the recommendation that extrastriatal D2-R measures obtained with [11C]raclopride should be interpreted with caution.
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| 10. |
- Gaudio, Santino, et al.
(författare)
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Higher fresh fruit intake relates to larger grey matter volumes in areas involved in dementia and depression : A UK Biobank study
- 2023
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Ingår i: NeuroImage. - : Elsevier. - 1053-8119 .- 1095-9572. ; 283
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Tidskriftsartikel (refereegranskat)abstract
- The benefits of consuming fruits and vegetables are widely accepted. While previous studies suggest a protective role of fruits and vegetables against a variety of diseases such as dementia and depression, the biological mechanisms/effects remain unclear. Here we investigated the effect of fruit and vegetable consumption on brain structure. Particularly on grey matter (GM) and white matter (WM) volumes, regional GM volumes and subcortical volumes. Cross-sectional imaging data from UK Biobank cohort was used. A total of 9925 participants (Mean age 62.4 +/- 7.5 years, 51.1 % men) were included in the present analysis. Measures included fruit and vegetable intake, other dietary patterns and a number of selected lifestyle factors and clinical data. Brain volumes were derived from structural brain magnetic resonance imaging. General linear model was used to study the associations between brain volumes and fruit/vegetable intakes. After adjusting for selected confounding factors, salad/raw vegetable intake showed a positive association with total white matter volume, fresh fruit intake showed a negative association with total grey matter (GM) volume. Regional GM analyses showed that higher fresh fruit intake was associated with larger GM volume in the left hippocampus, right temporal occipital fusiform cortex, left postcentral gyrus, right precentral gyrus, and right juxtapositional lobule cortex. We conclude that fruit and vegetable consumption seems to specifically modulate brain volumes. In particular, fresh fruit intake may have a protective role in specific cortical areas such as the hippocampus, areas robustly involved in the pathophysiology of dementia and depression.
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