Dopamine D2/3 Binding Potential Modulates Neural Signatures of Working Memory in a Load-Dependent Fashion.Visa övriga samt affilieringar
2019 (Engelska)Ingår i: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 39, nr 3, s. 537-547Artikel i tidskrift (Refereegranskat) 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.
Ort, förlag, år, upplaga, sidor
2019. Vol. 39, nr 3, s. 537-547
Nyckelord [en]
PET, aging, dopamine, fMRI, working memory
Nationell ämneskategori
Neurologi
Identifikatorer
URN: urn:nbn:se:umu:diva-155492DOI: 10.1523/JNEUROSCI.1493-18.2018ISI: 000455849400013PubMedID: 30478031Scopus ID: 2-s2.0-85060157566OAI: oai:DiVA.org:umu-155492DiVA, id: diva2:1280295
Forskningsfinansiär
VetenskapsrådetKnut och Alice Wallenbergs StiftelseTorsten Söderbergs stiftelseRagnar Söderbergs stiftelseHjärnfondenVästerbottens läns landsting2019-01-182019-01-182023-03-24Bibliografiskt granskad