title: Dopamine D2 receptor availability is linked to hippocampal-caudate functional connectivity and episodic memory.
abstract: 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 [(11)C]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.
authors.affiliation: Department of Radiation Sciences, Umeå University, S-901 87 Umeå, Sweden; Department of Integrative Medical Biology, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden; lars.nyberg@umu.se.
authors.forename: Lars
authors.initials: L
authors.lastname: Nyberg
authors.affiliation: Department of Radiation Sciences, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden;
authors.forename: Nina
authors.initials: N
authors.lastname: Karalija
authors.affiliation: Aging Research Center, Karolinska Institutet, S-11330 Stockholm, Sweden;
authors.forename: Alireza
authors.initials: A
authors.lastname: Salami
authors.affiliation: Department of Integrative Medical Biology, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden;
authors.forename: Micael
authors.initials: M
authors.lastname: Andersson
authors.affiliation: Department of Radiation Sciences, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden;
authors.forename: Anders
authors.initials: A
authors.lastname: Wåhlin
authors.affiliation: Aging Research Center, Karolinska Institutet, S-11330 Stockholm, Sweden;
authors.forename: Neda
authors.initials: N
authors.lastname: Kaboovand
authors.affiliation: Aging Research Center, Karolinska Institutet, S-11330 Stockholm, Sweden;
authors.forename: Ylva
authors.initials: Y
authors.lastname: Köhncke
authors.affiliation: Department of Radiation Sciences, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden;
authors.forename: Jan
authors.initials: J
authors.lastname: Axelsson
authors.affiliation: Department of Radiation Sciences, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden;
authors.forename: Anna
authors.initials: A
authors.lastname: Rieckmann
authors.affiliation: Aging Research Center, Karolinska Institutet, S-11330 Stockholm, Sweden;
authors.forename: Goran
authors.initials: G
authors.lastname: Papenberg
authors.affiliation: Center for Lifespan Psychology, Max Planck Institute for Human Development, D-14195 Berlin, Germany; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, D-14195 Berlin, Germany;
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Garrett
authors.affiliation: Department of Radiation Sciences, Umeå University, S-901 87 Umeå, Sweden; Umeå Center for Functional Brain Imaging, Umeå University, S-901 87 Umeå, Sweden;
authors.forename: Katrine
authors.initials: K
authors.lastname: Riklund
authors.affiliation: Aging Research Center, Karolinska Institutet, S-11330 Stockholm, Sweden;
authors.forename: Martin
authors.initials: M
authors.lastname: Lövdén
authors.affiliation: Center for Lifespan Psychology, Max Planck Institute for Human Development, D-14195 Berlin, Germany; Max Planck UCL Centre for Computational Psychiatry and Ageing Research, D-14195 Berlin, Germany; European University Institute, I-50014 San Domenico di Fiesole (FI), Italy.
authors.forename: Ulman
authors.identifier: 0000-0001-8428-6453
authors.initials: U
authors.lastname: Lindenberger
authors.affiliation: Aging Research Center, Karolinska Institutet, S-11330 Stockholm, Sweden;
authors.forename: Lars
authors.initials: L
authors.lastname: Bäckman
mesh_terms: D000368:Aged; D002421:Caudate Nucleus / Q000378:metabolism*; D003071:Cognition; D005260:Female; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged; D017448:Receptors, Dopamine D2 / Q000378:metabolism*
chemical_list: D017448:Receptors, Dopamine D2
keywords: dopamine; hippocampus; memory