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Karalija, Nina
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Publications (10 of 19) Show all publications
Karalija, N., Papenberg, G., Wåhlin, A., Johansson, J., Andersson, M., Axelsson, J., . . . Nyberg, L. (2019). C957T-mediated Variation in Ligand Affinity Affects the Association between C-11-raclopride Binding Potential and Cognition. Journal of cognitive neuroscience, 31(2), 314-325
Open this publication in new window or tab >>C957T-mediated Variation in Ligand Affinity Affects the Association between C-11-raclopride Binding Potential and Cognition
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2019 (English)In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. 31, no 2, p. 314-325Article in journal (Refereed) Published
Abstract [en]

The dopamine (DA) system plays an important role in cognition. Accordingly, normal variation in DA genes has been found to predict individual differences in cognitive performance. However, little is known of the impact of genetic differences on the link between empirical indicators of the DA system and cognition in humans. The present work used PET with C-11-raclopride to assess DA D2-receptor binding potential (BP) and links to episodic memory, working memory, and perceptual speed in 179 healthy adults aged 64-68 years. Previously, the T-allele of a DA D2-receptor single-nucleotide polymorphism, C957T, was associated with increased apparent affinity of C-11-raclopride, giving rise to higher BP values despite similar receptor density values between allelic groups. Consequently, we hypothesized that C-11-raclopride BP measures inflated by affinity rather than D2-receptor density in T-allele carriers would not be predictive of DA integrity and therefore prevent finding an association between C-11-raclopride BP and cognitive performance. In accordance with previous findings, we show that C-11-raclopride BP was increased in T-homozygotes. Importantly, C-11-raclopride BP was only associated with cognitive performance in groups with low or average ligand affinity (C-allele carriers of C957T, n = 124), but not in the high-affinity group (T-homozygotes, n = 55). The strongest C-11-raclopride BP-cognition associations and the highest level of performance were found in C-homozygotes. These findings show that genetic differences modulate the link between BP and cognition and thus have important implications for the interpretation of DA assessments with PET and C-11-raclopride in multiple disciplines ranging from cognitive neuroscience to psychiatry and neurology.

Place, publisher, year, edition, pages
MIT Press, 2019
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-155630 (URN)10.1162/jocn_a_01354 (DOI)000454429400011 ()30407135 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationRagnar Söderbergs stiftelseTorsten Söderbergs stiftelseThe Swedish Brain FoundationVästerbotten County Council
Available from: 2019-01-28 Created: 2019-01-28 Last updated: 2019-01-28Bibliographically approved
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
Karalija, N., Jonassson, L., Johansson, J., Papenberg, G., Salami, A., Andersson, M., . . . Boraxbekk, C.-J. (2019). High long-term test-retest reliability for extrastriatal C-11-raclopride binding in healthy older adults. Journal of Cerebral Blood Flow and Metabolism, Article ID UNSP 0271678X19874770.
Open this publication in new window or tab >>High long-term test-retest reliability for extrastriatal C-11-raclopride binding in healthy older adults
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2019 (English)In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, article id UNSP 0271678X19874770Article in journal (Refereed) Epub ahead of print
Abstract [en]

In vivo dopamine D2-receptor availability is frequently assessed with C-11-raclopride and positron emission tomography. Due to low signal-to-noise ratios for C-11-raclopride in areas with low D2 receptor densities, the ligand has been considered unreliable for measurements outside the dopamine-dense striatum. Intriguingly, recent studies show that extrastriatal C-11-raclopride binding potential (BPND) values are (i) reliably higher than in the cerebellum (where D2-receptor levels are negligible), (ii) correlate with behavior in the expected direction, and (iii) showed good test-retest reliability in a sample of younger adults. The present work demonstrates high seven-month test-retest reliability of striatal and extrastriatal C-11-raclopride BPND values in healthy, older adults (n = 27, age: 64-78 years). Mean C-11-raclopride BPND values were stable between test sessions in subcortical nuclei, and in frontal and temporal cortices (p > 0.05). Across all structures analyzed, intraclass correlation coefficients were high (0.85-0.96), absolute variability was low (mean: 4-8%), and coefficients of variance ranged between 9 and 25%. Furthermore, regional C-11-raclopride BPND values correlated with previously determined F-18-fallypride BPND values (rho = 0.97 and 0.92 in correlations with and without striatal values, respectively, p < 0.01) and postmortem determined D2-receptor densities (including striatum: rho = 0.92; p < 0.001; excluding striatum: rho = 0.75; p = 0.067). These observations suggest that extrastriatal C-11-raclopride measurements represent a true D2 signal.

Place, publisher, year, edition, pages
Sage Publications, 2019
Keywords
C-11-raclopride, binding potential, positron emission tomography, extrastriatal, reliability
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-164140 (URN)10.1177/0271678X19874770 (DOI)000487160200001 ()31506011 (PubMedID)
Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-17
Papenberg, G., Jonasson, L. S., Karalija, N., Johansson, J., Koehncke, Y., Salami, A., . . . Backman, L. (2019). Mapping the landscape of human dopamine D2/3 receptors with [11C]raclopride. Brain Structure and Function, 224(8), 2871-2882
Open this publication in new window or tab >>Mapping the landscape of human dopamine D2/3 receptors with [11C]raclopride
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2019 (English)In: Brain Structure and Function, ISSN 1863-2653, E-ISSN 1863-2661, Vol. 224, no 8, p. 2871-2882Article in journal (Refereed) Published
Abstract [en]

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.

Keywords
[C-11]raclopride, Dopamine D2, 3 receptors, Inter-individual differences, Structural-equation deling, COBRA study
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-165669 (URN)10.1007/s00429-019-01938-1 (DOI)000489147300018 ()31444615 (PubMedID)
Available from: 2019-12-06 Created: 2019-12-06 Last updated: 2019-12-06Bibliographically approved
af Bjerkén, S., Stenmark Persson, R., Barkander, A., Karalija, N., Pelegrina-Hidalgo, N., Gerhardt, G. A., . . . Strömberg, I. (2019). Noradrenaline is crucial for the substantia nigra dopaminergic cell maintenance. Neurochemistry International, 131, Article ID 104551.
Open this publication in new window or tab >>Noradrenaline is crucial for the substantia nigra dopaminergic cell maintenance
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2019 (English)In: Neurochemistry International, ISSN 0197-0186, E-ISSN 1872-9754, Vol. 131, article id 104551Article in journal (Refereed) Epub ahead of print
Abstract [en]

In Parkinson's disease, degeneration of substantia nigra dopaminergic neurons is accompanied by damage on other neuronal systems. A severe denervation is for example seen in the locus coerulean noradrenergic system. Little is known about the relation between noradrenergic and dopaminergic degeneration, and the effects of noradrenergic denervation on the function of the dopaminergic neurons of substantia nigra are not fully understood. In this study, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) was injected in rats, whereafter behavior, striatal KCl-evoked dopamine and glutamate releases, and immunohistochemistry were monitored at 3 days, 3 months, and 6 months. Quantification of dopamine-beta-hydroxylase-immunoreactive nerve fiber density in the cortex revealed a tendency towards nerve fiber regeneration at 6 months. To sustain a stable noradrenergic denervation throughout the experimental timeline, the animals in the 6-month time point received an additional DSP4 injection (2 months after the first injection). Behavioral examinations utilizing rotarod revealed that DSP4 reduced the time spent on the rotarod at 3 but not at 6 months. KCl-evoked dopamine release was significantly increased at 3 days and 3 months, while the concentrations were normalized at 6 months. DSP4 treatment prolonged both time for onset and reuptake of dopamine release over time. The dopamine degeneration was confirmed by unbiased stereology, demonstrating significant loss of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra. Furthermore, striatal glutamate release was decreased after DSP4. In regards of neuroinflammation, reactive microglia were found over the substantia nigra after DSP4 treatment. In conclusion, long-term noradrenergic denervation reduces the number of dopaminergic neurons in the substantia nigra and affects the functionality of the nigrostriatal system. Thus, locus coeruleus is important for maintenance of nigral dopaminergic neurons.

Keywords
DSP4, Dopamine, In vivo amperometry, In vivo chronoamperometry, Noradrenaline, Parkinson's disease
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-163942 (URN)10.1016/j.neuint.2019.104551 (DOI)31542295 (PubMedID)2-s2.0-85072404826 (Scopus ID)
Available from: 2019-10-09 Created: 2019-10-09 Last updated: 2019-10-10
Papenberg, G., Karalija, N., Salami, A., Andersson, M., Axelsson, J., Riklund, K., . . . Bäckman, L. (2019). The Influence of Hippocampal Dopamine D2 Receptors on Episodic Memory Is Modulated by BDNF and KIBRA Polymorphisms. Journal of cognitive neuroscience, 31(9), 1422-1429
Open this publication in new window or tab >>The Influence of Hippocampal Dopamine D2 Receptors on Episodic Memory Is Modulated by BDNF and KIBRA Polymorphisms
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2019 (English)In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. 31, no 9, p. 1422-1429Article in journal (Refereed) Published
Abstract [en]

Episodic memory is a polygenic trait influenced by different molecular mechanisms. We used PET and a candidate gene approach to investigate how individual differences at the molecular level translate into between-person differences in episodic memory performance of elderly persons. Specifically, we examined the interactive effects between hippocampal dopamine D2 receptor (D2DR) availability and candidate genes relevant for hippocampus-related memory functioning. We show that the positive effects of high D2DR availability in the hippocampus on episodic memory are confined to carriers of advantageous genotypes of the brain-derived neurotrophic factor (BDNF, rs6265) and the kidney and brain expressed protein (KIBRA, rs17070145) polymorphisms. By contrast, these polymorphisms did not modulate the positive relationship between caudate D2DR availability and episodic memory.

Place, publisher, year, edition, pages
MIT Press, 2019
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-162391 (URN)10.1162/jocn_a_01429 (DOI)000477974100012 ()31112471 (PubMedID)2-s2.0-85070257740 (Scopus ID)
Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2019-08-20Bibliographically 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
Salami, A., Rieckmann, A., Karalija, N., Avelar-Pereira, B., Andersson, M., Wåhlin, A., . . . Nyberg, L. (2018). Neurocognitive Profiles of Older Adults with Working-Memory Dysfunction. Cerebral Cortex, 28(7), 2525-2539
Open this publication in new window or tab >>Neurocognitive Profiles of Older Adults with Working-Memory Dysfunction
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2018 (English)In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 28, no 7, p. 2525-2539Article in journal (Refereed) Published
Abstract [en]

Individuals differ in how they perceive, remember, and think. There is evidence for the existence of distinct subgroups that differ in cognitive performance within the older population. However, it is less clear how individual differences in cognition in old age are linked to differences in brain-based measures. We used latent-profile analysis on n-back working-memory (WM) performance to identify subgroups in a large sample of older adults (n = 181; age = 64-68 years). Our analysis identified one larger normal subgroup with higher performance (n = 113; 63%), and a second smaller subgroup (n = 55; 31%) with lower performance. The low-performing subgroup showed weaker load-dependent BOLD modulation and lower connectivity within the fronto-parietal network (FPN) as well as between FPN and striatum during n-back, along with lower FPN connectivity at rest. This group also exhibited lower FPN structural integrity, lower frontal dopamine D2 binding potential, inferior performance on offline WM tests, and a trend-level genetic predisposition for lower dopamine-system efficiency. By contrast, this group exhibited relatively intact episodic memory and associated brain measures (i.e., hippocampal volume, structural, and functional connectivity within the default-mode network). Collectively, these data provide converging evidence for the existence of a group of older adults with impaired WM functioning characterized by reduced cortico-striatal coupling and aberrant cortico-cortical integrity within FPN.

Place, publisher, year, edition, pages
Oxford University Press, 2018
Keywords
dopamine, fronto-parietal network, functional connectivity, individual differences, working memory
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-150747 (URN)10.1093/cercor/bhy062 (DOI)000437165800025 ()29901790 (PubMedID)
Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-08-16Bibliographically approved
Nyberg, L., Karalija, N., Salami, A., Andersson, M., Wåhlin, A., Kaboovand, N., . . . Bäckman, L. (2016). Dopamine D2 receptor availability is linked to hippocampal-caudate functional connectivity and episodic memory. Proceedings of the National Academy of Sciences of the United States of America, 113(28), 7918-7923
Open this publication in new window or tab >>Dopamine D2 receptor availability is linked to hippocampal-caudate functional connectivity and episodic memory
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2016 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 113, no 28, p. 7918-7923Article in journal (Refereed) Published
Abstract [en]

D1 and D2 dopamine receptors (D1DRs and D2DRs) may contribute differently to various aspects of memory and cognition. The D1DR system has been linked to functions supported by the prefrontal cortex. By contrast, the role of the D2DR system is less clear, although it has been hypothesized that D2DRs make a specific contribution to hippocampus-based cognitive functions. Here we present results from 181 healthy adults between 64 and 68 y of age who underwent comprehensive assessment of episodic memory, working memory, and processing speed, along with MRI and D2DR assessment with [C-11]raclopride and PET. Caudate D2DR availability was positively associated with episodic memory but not with working memory or speed. Whole-brain analyses further revealed a relation between hippocampal D2DR availability and episodic memory. Hippocampal and caudate D2DR availability were interrelated, and functional MRI-based resting-state functional connectivity between the ventral caudate and medial temporal cortex increased as a function of caudate D2DR availability. Collectively, these findings indicate that D2DRs make a specific contribution to hippocampus-based cognition by influencing striatal and hippocampal regions, and their interactions.

Keywords
dopamine, memory, hippocampus
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-124327 (URN)10.1073/pnas.1606309113 (DOI)000379694100063 ()27339132 (PubMedID)
Available from: 2016-12-13 Created: 2016-08-04 Last updated: 2018-06-09Bibliographically approved
Nevalainen, N., Riklund, K., Andersson, M., Axelsson, J., Ögren, M., Lövdén, M., . . . Nyberg, L. (2015). COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition.. Brain Research, 1612, 83-103
Open this publication in new window or tab >>COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition.
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2015 (English)In: Brain Research, ISSN 0006-8993, E-ISSN 1872-6240, Vol. 1612, p. 83-103Article in journal (Refereed) Published
Abstract [en]

Cognitive decline is a characteristic feature of normal human aging. Previous work has demonstrated marked interindividual variability in onset and rate of decline. Such variability has been linked to factors such as maintenance of functional and structural brain integrity, genetics, and lifestyle. Still, few, if any, studies have combined a longitudinal design with repeated multimodal imaging and a comprehensive assessment of cognition as well as genetic and lifestyle factors. The present paper introduces the Cognition, Brain, and Aging (COBRA) study, in which cognitive performance and brain structure and function are measured in a cohort of 181 older adults aged 64 to 68 years at baseline. Participants will be followed longitudinally over a 10-year period, resulting in a total of three equally spaced measurement occasions. The measurement protocol at each occasion comprises a comprehensive set of behavioral and imaging measures. Cognitive performance is evaluated via computerized testing of working memory, episodic memory, perceptual speed, motor speed, implicit sequence learning, and vocabulary. Brain imaging is performed using positron emission tomography with [(11)C]-raclopride to assess dopamine D2/D3 receptor availability. Structural magnetic resonance imaging (MRI) is used for assessment of white and gray-matter integrity and cerebrovascular perfusion, and functional MRI maps brain activation during rest and active task conditions. Lifestyle descriptives are collected, and blood samples are obtained and stored for future evaluation. Here, we present selected results from the baseline assessment along with a discussion of sample characteristics and methodological considerations that determined the design of the study.

Keywords
Aging, Cognitive decline, Striatum, Magnetic resonance imaging (MRI), Positron emission tomography (PET), [ 11C]-raclopride
National Category
Physiology Neurosciences
Identifiers
urn:nbn:se:umu:diva-93568 (URN)10.1016/j.brainres.2014.09.010 (DOI)000356551700008 ()25239478 (PubMedID)
Available from: 2014-09-25 Created: 2014-09-25 Last updated: 2018-06-07Bibliographically approved
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