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Jonasson, Lars S.
Alternative names
Publications (10 of 13) Show all publications
Salami, A., Garrett, D. D., Wåhlin, A., Rieckmann, A., Papenberg, G., Karalija, N., . . . Nyberg, L. (2019). Dopamine D2/3 Binding Potential Modulates Neural Signatures of Working Memory in a Load-Dependent Fashion.. Journal of Neuroscience, 39(3), 537-547
Open this publication in new window or tab >>Dopamine D2/3 Binding Potential Modulates Neural Signatures of Working Memory in a Load-Dependent Fashion.
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2019 (English)In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 39, no 3, p. 537-547Article in journal (Refereed) Published
Abstract [en]

Dopamine (DA) modulates corticostriatal connections. Studies in which imaging of the DA system is integrated with functional imaging during cognitive performance have yielded mixed findings. Some work has shown a link between striatal DA (measured by PET) and fMRI activations, whereas others have failed to observe such a relationship. One possible reason for these discrepant findings is differences in task demands, such that a more demanding task with greater prefrontal activations may yield a stronger association with DA. Moreover, a potential DA–BOLD association may be modulated by task performance. We studied 155 (104 normal-performing and 51 low-performing) healthy older adults (43% females) who underwent fMRI scanning while performing a working memory (WM) n-back task along with DA D2/3 PET assessment using [11C]raclopride. Using multivariate partial-least-squares analysis, we observed a significant pattern revealing positive associations of striatal as well as extrastriatal DA D2/3 receptors to BOLD response in the thalamo–striatal–cortical circuit, which supports WM functioning. Critically, the DA–BOLD association in normal-performing, but not low-performing, individuals was expressed in a load-dependent fashion, with stronger associations during 3-back than 1-/2-back conditions. Moreover, normal-performing adults expressing upregulated BOLD in response to increasing task demands showed a stronger DA–BOLD association during 3-back, whereas low-performing individuals expressed a stronger association during 2-back conditions. This pattern suggests a nonlinear DA–BOLD performance association, with the strongest link at the maximum capacity level. Together, our results suggest that DA may have a stronger impact on functional brain responses during more demanding cognitive tasks.

Keywords
PET, aging, dopamine, fMRI, working memory
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-155492 (URN)10.1523/JNEUROSCI.1493-18.2018 (DOI)000455849400013 ()30478031 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationTorsten Söderbergs stiftelseRagnar Söderbergs stiftelseThe Swedish Brain FoundationVästerbotten County Council
Available from: 2019-01-18 Created: 2019-01-18 Last updated: 2019-02-08Bibliographically approved
Jonasson, L. S., Nyberg, L., Axelsson, J., Kramer, A. F., Riklund, K. & Boraxbekk, C.-J. (2019). Higher striatal D2-receptor availability in aerobically fit older adults but non-selective intervention effects after aerobic versus resistance training. NeuroImage, 202, Article ID 116044.
Open this publication in new window or tab >>Higher striatal D2-receptor availability in aerobically fit older adults but non-selective intervention effects after aerobic versus resistance training
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2019 (English)In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 202, article id 116044Article in journal (Refereed) Published
Abstract [en]

There is much evidence that dopamine is vital for cognitive functioning in aging. Here we tested the hypothesis that aerobic exercise and fitness influence dopaminergic neurotransmission in the striatum, and in turn performance on offline working-memory updating tasks. Dopaminergic neurotransmission was measured by positron emission tomography (PET) and the non-displacable binding potential (BPND) of [11C]raclopride, i.e. dopamine (DA) D2-receptor (D2R) availability. Fifty-four sedentary older adults underwent a six-months exercise intervention, performing either aerobic exercise or stretching, toning, and resistance active control training. At baseline, higher aerobic fitness levels (VO2peak) were associated with higher BPND in the striatum, providing evidence of a link between an objective measure of aerobic fitness and D2R in older adults. BPND decreased substantially over the intervention in both groups but the intervention effects were non-selective with respect to exercise group. The decrease was several times larger than any previously estimated annual decline in D2R, potentially due to increased endogenous DA. Working-memory was unrelated to D2R both at baseline and following the intervention. To conclude, we provide partial evidence for a link between physical exercise and DA. Utilizing a PET protocol able to disentangle both D2R and DA levels could shed further light on whether, and how, aerobic exercise impacts the dopaminergic system in older adults.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Aerobic exercise, Fitness, Dopamine, D2, Working memory, Raclopride
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-162742 (URN)10.1016/j.neuroimage.2019.116044 (DOI)31352122 (PubMedID)2-s2.0-85069908673 (Scopus ID)
Available from: 2019-08-27 Created: 2019-08-27 Last updated: 2019-08-30Bibliographically approved
Jakobson Mo, S., Axelsson, J., Jonasson, L., Larsson, A., Ögren, M. J., Ögren, M., . . . Riklund, K. (2018). Dopamine transporter imaging with [18F]FE-PE2I PET and [123I]FP-CIT SPECT – a clinical comparison. EJNMMI Research, 8, Article ID 100.
Open this publication in new window or tab >>Dopamine transporter imaging with [18F]FE-PE2I PET and [123I]FP-CIT SPECT – a clinical comparison
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2018 (English)In: EJNMMI Research, ISSN 2191-219X, E-ISSN 2191-219X, Vol. 8, article id 100Article in journal (Refereed) Published
Abstract [en]

Background: Dopamine transporter (DAT) imaging may be of diagnostic value in patients with clinically suspected parkinsonian disease. The purpose of this study was to compare the diagnostic performance of DAT imaging with positron emission computed tomography (PET), using the recently developed, highly DAT-selective radiopharmaceutical [18F]FE-PE2I (FE-PE2I), to the commercially available and frequently used method with [123I]FP-CIT (FP-CIT) single-photon emission computed tomography (SPECT) in early-stage idiopathic parkinsonian syndrome (PS).

Methods: Twenty-two patients with a clinical de novo diagnosis of PS and 28 healthy controls (HC) participating in an on-going clinical trial of FE-PE2I were analyzed in this study. Within the trial protocol, participants are clinically reassessed 2 years after inclusion. A commercially available software was used for automatic calculation of FP-CIT-specific uptake ratio (SUR). MRI-based volumes of interest combined with threshold PET segmentation were used for FE-PE2I binding potential relative to non-displaceable binding (BPND) quantification and specific uptake value ratios (SUVR).

Results: PET with FE-PE2I revealed significant differences between patients with a clinical de novo diagnosis of PS and healthy controls in striatal DAT availability (p < 0.001), with excellent accuracy of predicting dopaminergic deficit in early-stage PS. The effect sizes were calculated for FE-PE2I BPND (Glass’s Δ = 2.95), FE-PE2I SUVR (Glass’s Δ = 2.57), and FP-CIT SUR (Glass’s Δ = 2.29). The intraclass correlation (ICC) between FE-PE2I BPND FP-CIT SUR was high in the caudate (ICC = 0.923), putamen (ICC = 0.922), and striatum (ICC = 0.946), p < 0.001. Five of the 22 patients displayed preserved striatal DAT availability in the striatum with both methods. At follow-up, a non-PS clinical diagnosis was confirmed in three of these, while one was clinically diagnosed with corticobasal syndrome. In these patients, FE-PE2I binding was also normal in the substantia nigra (SN), while significantly reduced in the remaining patients. FE-PE2I measurement of the mean DAT availability in the putamen was strongly correlated with BPND in the SN (R = 0.816, p < 0.001). Olfaction and mean putamen DAT availability was correlated using both FE-PE2I BPND and FP-CIT SUR (R ≥ 0.616, p < 0.001).

Conclusion: DAT imaging with FE-PE2I PET yields excellent basic diagnostic differentiation in early-stage PS, at least as good as FP-CIT SPECT.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Parkinson's disease, PET, SPECT, Dopamine transporter (DAT), [F-18]FE-PE2I
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-154944 (URN)10.1186/s13550-018-0450-0 (DOI)000450488800002 ()30443684 (PubMedID)
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-05-07Bibliographically approved
Lövdén, M., Karalija, N., Andersson, M., Wåhlin, A., Axelsson, J., Köhncke, Y., . . . Lindenberger, U. (2018). Latent-profile analysis reveals behavioral and brain correlates of dopamine-cognition associations. Cerebral Cortex, 28(11), 3894-3907
Open this publication in new window or tab >>Latent-profile analysis reveals behavioral and brain correlates of dopamine-cognition associations
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2018 (English)In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 28, no 11, p. 3894-3907Article in journal (Refereed) Published
Abstract [en]

Evidence suggests that associations between the neurotransmitter dopamine and cognition are nonmonotonic and open to modulation by various other factors. The functional implications of a given level of dopamine may therefore differ from person to person. By applying latent-profile analysis to a large (n = 181) sample of adults aged 64-68 years, we probabilistically identified 3 subgroups that explain the multivariate associations between dopamine D2/3R availability (probed with C-11-raclopride-PET, in cortical, striatal, and hippocampal regions) and cognitive performance (episodic memory, working memory, and perceptual speed). Generally, greater receptor availability was associated with better cognitive performance. However, we discovered a subgroup of individuals for which high availability, particularly in striatum, was associated with poor performance, especially for working memory. Relative to the rest of the sample, this subgroup also had lower education, higher body-mass index, and lower resting-state connectivity between caudate nucleus and dorsolateral prefrontal cortex. We conclude that a smaller subset of individuals induces a multivariate non-linear association between dopamine D2/3R availability and cognitive performance in this group of older adults, and discuss potential reasons for these differences that await further empirical scrutiny.

Place, publisher, year, edition, pages
Oxford University Press, 2018
Keywords
Cognitive Performance, dopamine D-2/3 Receptor Availability, Heterogeneity, Latent Profile Analysis, older Adults, Working Memory
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-153657 (URN)10.1093/cercor/bhx253 (DOI)000449432200011 ()29028935 (PubMedID)
Funder
Swedish Research Council, 446-2013-7189Forte, Swedish Research Council for Health, Working Life and Welfare, 2013-2277Knut and Alice Wallenberg FoundationTorsten Söderbergs stiftelseRagnar Söderbergs stiftelseThe Swedish Brain FoundationVästerbotten County Council
Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2018-11-26Bibliographically approved
Pantzar, A., Jonasson, L. S., Ekblom, O., Boraxbekk, C.-J. & Ekblom, M. M. (2018). Relationships Between Aerobic Fitness Levels and Cognitive Performance in Swedish Office Workers. Frontiers in Psychology, 9, Article ID 2612.
Open this publication in new window or tab >>Relationships Between Aerobic Fitness Levels and Cognitive Performance in Swedish Office Workers
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2018 (English)In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 9, article id 2612Article in journal (Refereed) Published
Abstract [en]

Objectives: Aerobic exercise influence cognition in elderly, children, and neuropsychiatric populations. Less is known about the influence of aerobic exercise in healthy samples (particularly working age), and of different fitness levels on cognition. Two hypotheses were posed: (1) low fitness levels, compared to moderate and high, will be related to poorer cognitive performance, and (2) breakpoints for the beneficial relationship between VO2 and cognition will be observed within the moderate-to-high fitness span.

Design and Methods: The sample consisted of n=362 office workers. A submaximal cycle ergometer test estimated maximal oxygen consumption (VO2max, mL·kg−1·min−1). Based on estimated VO2max participants were split into tertiles; low (n = 121), moderate (n = 119), and high (n = 122). A cognitive test battery (9 tests), assessed processing speed, working memory, executive functions and episodic memory.

Results: Both hypotheses were confirmed. Groups of moderate (≈40) and high (≈49) fitness outperformed the group of low (≈31) fitness for inhibition and episodic recognition, whereas no significant differences between moderate and high fitness were observed (ANCOVAs). Breakpoints between benefits fromVO2maxfor inhibition and recognition were estimated to ≈44/43 mL·kg−1·min−1 (multivariate broken line regressions).

Conclusions: Results suggest that it is conceivable to expect a beneficial relationship between VO2max and some cognitive domains up to a certain fitness level. In a sample of healthy office workers, this level was estimated to 44 mL·kg−1·min−1. This has implications on organizational and societal levels; where incentives to improve fitness levels from low to moderate could yield desirable cognitive and health benefits in adults.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2018
Keywords
cognition, aerobic fitness, office workers, broken line regression, exercise and cognition
National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-155096 (URN)10.3389/fpsyg.2018.02612 (DOI)000453917400001 ()
Funder
Knowledge Foundation, 20160040
Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-01-10Bibliographically approved
Koehncke, Y., Papenberg, G., Jonasson, L. S., Karalija, N., Wåhlin, A., Salami, A., . . . Lövdén, M. (2018). Self-rated intensity of habitual physical activities is positively associated with dopamine D-2/3 receptor availability and cognition. NeuroImage, 181, 605-616
Open this publication in new window or tab >>Self-rated intensity of habitual physical activities is positively associated with dopamine D-2/3 receptor availability and cognition
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2018 (English)In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 181, p. 605-616Article in journal (Refereed) Published
Abstract [en]

Between-person differences in cognitive performance in older age are associated with variations in physical activity. The neurotransmitter dopamine (DA) contributes to cognitive performance, and the DA system deteriorates with advancing age. Animal data and a patient study suggest that physical activity modulates DA receptor availability, but data from healthy humans are lacking. In a cross-sectional study with 178 adults aged 64-68 years, we investigated links among self-reported physical activity, D(2/3)DA receptor (D2/3DR) availability, and cognitive performance. D2/3DR availability was measured with [C-11]raclopride positron emission tomography at rest. We used structural equation modeling to obtain latent factors for processing speed, episodic memory, working memory, physical activity, and D2/3DR availability in caudate, putamen, and hippocampus. Physical activity intensity was positively associated with D2/3DR availability in caudate, but not putamen and hippocampus. Frequency of physical activity was not related to D2/3DR availability. Physical activity intensity was positively related to episodic memory and working memory. D2/3DR availability in caudate and hippocampus was positively related to episodic memory. Taken together, our results suggest that striatal DA availability might be a neurochemical correlate of episodic memory that is also associated with physical activity.

Place, publisher, year, edition, pages
Academic Press, 2018
Keywords
Cognition, Episodic memory, Dopamine, Physical activity, Aging
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-152374 (URN)10.1016/j.neuroimage.2018.07.036 (DOI)000445165600053 ()30041059 (PubMedID)
Funder
Swedish Research Council, 446-2013-7189Forte, Swedish Research Council for Health, Working Life and Welfare, 2013-2277Knut and Alice Wallenberg FoundationRagnar Söderbergs stiftelseTorsten Söderbergs stiftelseThe Swedish Brain FoundationVästerbotten County Council
Available from: 2018-10-05 Created: 2018-10-05 Last updated: 2018-10-05Bibliographically approved
Jonasson, L., Nyberg, L., Kramer, A., Lundquist, A., Riklund, K. & Boraxbekk, C.-J. (2017). Aerobic Exercise Intervention, CognitivePerformance, and Brain Structure: results from the Physical Influences on Brain in Aging (PHIBRA) Study. Frontiers in Aging Neuroscience, 8, 1-15, Article ID 336.
Open this publication in new window or tab >>Aerobic Exercise Intervention, CognitivePerformance, and Brain Structure: results from the Physical Influences on Brain in Aging (PHIBRA) Study
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2017 (English)In: Frontiers in Aging Neuroscience, ISSN 1663-4365, E-ISSN 1663-4365, Vol. 8, p. 1-15, article id 336Article in journal (Refereed) Published
Abstract [en]

Studies have shown that aerobic exercise has the potential to improve cognition and reduce brain atrophy in older adults. However, the literature is equivocal with regards to the specificity or generality of these effects. To this end, we report results on cognitive function and brain structure from a 6-month training intervention with 60 sedentary adults (64–78 years) randomized to either aerobic training or stretching and toning control training. Cognitive functions were assessed with a neuropsychological test battery in which cognitive constructs were measured using several different tests. Freesurfer was used to estimate cortical thickness in frontal regions and hippocampus volume. Results showed that aerobic exercisers, compared to controls, exhibited a broad, rather than specific, improvement in cognition as indexed by a higher “Cognitive score,” a composite including episodic memory, processing speed, updating, and executive function tasks (p = 0.01). There were no group differences in cortical thickness, but additional analyses revealed that aerobic fitness at baseline was specifically related to larger thickness in dorsolateral prefrontal cortex (dlPFC), and hippocampus volume was positively associated with increased aerobic fitness over time. Moreover, “Cognitive score” was related to dlPFC thickness at baseline, but changes in “Cognitive score” and dlPFC thickness were associated over time in the aerobic group only. However, aerobic fitness did not predict dlPFC change, despite the improvement in “Cognitive score” in aerobic exercisers. Our interpretation of these observations is that potential exercise-induced changes in thickness are slow, and may be undetectable within 6-months, in contrast to change in hippocampus volume which in fact was predicted by the change in aerobic fitness. To conclude, our results add to a growing literature suggesting that aerobic exercise has a broad influence on cognitive functioning, which may aid in explaining why studies focusing on a narrower range of functions have sometimes reported mixed results.

Keywords
aerobic exercise, cognition, executive function, plasticity, hippocampus, prefrontal cortex, freesurfer, transfer
National Category
Neurosciences Sport and Fitness Sciences Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:umu:diva-130526 (URN)10.3389/fnagi.2016.00336 (DOI)000392049000001 ()
Funder
Swedish Research Council, 2012- 00530
Available from: 2017-01-22 Created: 2017-01-22 Last updated: 2018-06-09Bibliographically approved
Jonasson, L. (2017). Aerobic fitness and healthy brain aging: cognition, brain structure, and dopamine. (Doctoral dissertation). Umeå: Umeå Universitet
Open this publication in new window or tab >>Aerobic fitness and healthy brain aging: cognition, brain structure, and dopamine
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Aerobisk träning och hjärnans hälsosamma åldrande : kognition, hjärnstruktur och dopamin
Abstract [en]

Background: Performing aerobic exercise and maintaining high levels of aerobic fitness may have positive effects on both brain structure and function in older adults. Despite decades of research however, there is still a rather poor understanding of the neurocognitive mechanisms explaining the positive effects of aerobic exercise on cognition. Changes in prefrontal gray matter as well as dopaminergic neurotransmission in striatum are both candidate neurocognitive mechanisms. The main aims of this thesis are: 1. To investigate the effects of aerobic exercise and fitness on cognition and magnetic resonance imaging (MRI) derived gray matter volumes using data from a 6 month physical exercise intervention in older adults (Study I). 2. To simulate the effect of atrophy in longitudinal positron emission tomography (PET) which could pose a challenge to interpreting changes in longitudinal PET imaging (Study II). 3. To study the influence of aerobic exercise and fitness on the dopamine D2-receptor (D2R) system in striatum using [11C]raclopride PET as a potential mechanism for improved cognition (Study III).

Results: In Study I, aerobic exercise was found to improve cognitive performance in a broad, rather than domain-specific sense. Moreover, aerobic fitness was related to prefrontal cortical thickness, and improved aerobic fitness over 6 months was related to increased hippocampal volume. In Study II, we identified areas in the striatum vulnerable to the effect of shrinkage, which should be considered in longitudinal PET imaging. Finally, in Study III, the effect of being aerobically fit, and improving fitness levels was found to impact dopaminergic neurotransmission in the striatum, which in turn mediated fitness-induced improvements in working memory updating performance.

Conclusion: The findings in this thesis provide novel evidence regarding the neurocognitive mechanisms of aerobic exercise-induced improvements in cognition, and impacts the interpretation of longitudinal PET imaging. Performing aerobic exercise and staying aerobically fit at an older age have positive effects on cognition and brain systems important for memory and cognition. Specifically, fitness-induced changes to the dopaminergic system stands out as one novel neurocognitive mechanism explaining the positive effects of aerobic fitness on working-memory performance in healthy older adults.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2017. p. 81
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1908
Keywords
Aerobic exercise, VO2, working memory, executive function, freesurfer, striatum, dopamine, D2-receptors, [11C]raclopride
National Category
Neurosciences Sport and Fitness Sciences
Identifiers
urn:nbn:se:umu:diva-139056 (URN)978-91-7601-753-1 (ISBN)
Public defence
2017-09-29, Sal 933, Building 3B, Norrland University Hospital, Umeå, 09:35 (English)
Opponent
Supervisors
Available from: 2017-09-08 Created: 2017-09-06 Last updated: 2018-06-09Bibliographically approved
Flodin, P., Jonasson, L., Riklund, K., Nyberg, L. & Boraxbekk, C.-J. (2017). Does Aerobic Exercise Influence Intrinsic Brain Activity? An Aerobic Exercise Intervention among Healthy Old Adults. Frontiers in Aging Neuroscience, 9, Article ID 267.
Open this publication in new window or tab >>Does Aerobic Exercise Influence Intrinsic Brain Activity? An Aerobic Exercise Intervention among Healthy Old Adults
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2017 (English)In: Frontiers in Aging Neuroscience, ISSN 1663-4365, E-ISSN 1663-4365, Vol. 9, article id 267Article in journal (Refereed) Published
Abstract [en]

Previous studies have indicated that aerobic exercise could reduce age related decline in cognition and brain functioning. Here we investigated the effects of aerobic exercise on intrinsic brain activity. Sixty sedentary healthy males and females (64–78 years) were randomized into either an aerobic exercise group or an active control group. Both groups recieved supervised training, 3 days a week for 6 months. Multimodal brain imaging data was acquired before and after the intervention, including 10 min of resting state brain functional magnetic resonance imaging (rs-fMRI) and arterial spin labeling (ASL). Additionally, a comprehensive battery of cognitive tasks assessing, e.g., executive function and episodic memory was administered. Both the aerobic and the control group improved in aerobic capacity (VO2-peak) over 6 months, but a significant group by time interaction confirmed that the aerobic group improved more. Contrary to our hypothesis, we did not observe any significant group by time interactions with regard to any measure of intrinsic activity. To further probe putative relationships between fitness and brain activity, we performed post hoc analyses disregarding group belongings. At baseline, VO2-peak was negativly related to BOLD-signal fluctuations (BOLDSTD) in mid temporal areas. Over 6 months, improvements in aerobic capacity were associated with decreased connectivity between left hippocampus and contralateral precentral gyrus, and positively to connectivity between right mid-temporal areas and frontal and parietal regions. Independent component analysis identified a VO2-related increase in coupling between the default mode network and left orbitofrontal cortex, as well as a decreased connectivity between the sensorimotor network and thalamus. Extensive exploratory data analyses of global efficiency, connectome wide multivariate pattern analysis (connectome-MVPA), as well as ASL, did not reveal any relationships between aerobic fitness and intrinsic brain activity. Moreover, fitness-predicted changes in functional connectivity did not relate to changes in cognition, which is likely due to absent cross- sectional or longitudinal relationships between VO2-peak and cognition. We conclude that the aerobic exercise intervention had limited influence on patterns of intrinsic brain activity, although post hoc analyses indicated that individual changes in aerobic capacity preferentially influenced mid-temporal brain areas.

Keywords
aerobic exercise, brain plasticity, aging, fMRI, resting-state, ASL
National Category
Sport and Fitness Sciences
Research subject
Neurology; Psychology
Identifiers
urn:nbn:se:umu:diva-138285 (URN)10.3389/fnagi.2017.00267 (DOI)000407499200001 ()28848424 (PubMedID)
Projects
Physical Influences on Brain in Aging (PHIBRA)
Funder
Swedish Research Council, 2012-00530Swedish Research Council, Dnr 2013 – 2056Västerbotten County Council
Available from: 2017-08-16 Created: 2017-08-16 Last updated: 2018-06-09Bibliographically approved
Jonasson, L., Axelsson, J., Riklund, K. & Boraxbekk, C.-J. (2017). Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom. Physics in Medicine and Biology, 62(13), 5213-5227
Open this publication in new window or tab >>Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom
2017 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 62, no 13, p. 5213-5227Article in journal (Refereed) Published
Abstract [en]

In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered- subsets maximization algorithm with spatially variant point-spread function resolution modeling provided the most accurate data. For striatum, the BP changed by 0.08% for every 1% volume change, but for smaller volumes such as the posterior caudate the artificial change in BP was as high as 0.7% per 1% volume change. A simple gross correction for striatal volume is unsatisfactory, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology, combined with the wall removal method, can be implemented to gain knowledge about the predictable bias introduced by the PVE differences in uptake regions of varying shape.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2017
Keywords
longitudinal, PET, partial volume effect, brain phantom, dopamine
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
radiofysik
Identifiers
urn:nbn:se:umu:diva-136030 (URN)10.1088/1361-6560/aa6e1b (DOI)000402879700001 ()28561014 (PubMedID)
Available from: 2017-06-13 Created: 2017-06-13 Last updated: 2018-06-09Bibliographically approved
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