| 1. |
- Köhncke, Ylva, et al.
(författare)
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Self-rated intensity of habitual physical activities is positively associated with dopamine D-2/3 receptor availability and cognition
- 2018
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 181, s. 605-616
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Lövdén, Martin, et al.
(författare)
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Latent-Profile Analysis Reveals Behavioral and Brain Correlates of Dopamine-Cognition Associations
- 2018
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Ingår i: Cerebral Cortex. - : Oxford University Press (OUP). - 1047-3211 .- 1460-2199. ; 28:11, s. 3894-3907
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Papenberg, Goran, et al.
(författare)
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Mapping the landscape of human dopamine D2/3 receptors with [11C]raclopride
- 2019
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Ingår i: Brain Structure and Function. - : Springer Science and Business Media LLC. - 1863-2653 .- 1863-2661. ; 224:8, s. 2871-2882
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Tidskriftsartikel (refereegranskat)abstract
- The dopamine D2/3 system is fundamental for sensory, motor, emotional, and cognitive aspects of behavior. Small-scale human histopathological and animal studies show high density of D2/3 dopamine receptors (D2/3DR) in striatum, but also demonstrate the existence of such receptors across cortical and limbic regions. Assessment of D2/3DR BPND in the extrastriatal regions with [C-11]raclopride has long been considered unreliable due to the relatively low density of D2/3DR outside the striatum. We describe the distribution and interregional links of D2/3DR availability measured with PET and [C-11]raclopride across the human brain in a large sample (N = 176; age range 64-68 years). Structural equation modeling revealed that D2/3DR availability can be organized according to anatomical (nigrostriatal, mesolimbic, mesocortical) and functional (limbic, associative, sensorimotor) dopamine pathways. D2/3DR availability in corticolimbic functional subdivisions showed differential associations to corresponding striatal subdivisions, extending animal and pharmacological work. Our findings provide evidence on the dimensionality and organization of [C-11]raclopride D2/3DR availability in the living human brain that conforms to known dopaminergic pathways.
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| 4. |
- Jonasson, Lars S., 1983-, et al.
(författare)
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Higher striatal D2-receptor availability in aerobically fit older adults but non-selective intervention effects after aerobic versus resistance training
- 2019
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Ingår i: NeuroImage. - : Elsevier. - 1053-8119 .- 1095-9572. ; 202
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Pantzar, Alexandra, et al.
(författare)
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Relationships Between Aerobic Fitness Levels and Cognitive Performance in Swedish Office Workers
- 2018
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Ingår i: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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