title: Combined effect of genetic variants in the GluN2B coding gene (GRIN2B) on prefrontal function during working memory performance.
abstract: BACKGROUND
  The GluN2B subunit of N-methyl-d-aspartate receptors is crucially involved in the physiology of the prefrontal cortex during working memory (WM). Consistently, genetic variants in the GluN2B coding gene (GRIN2B) have been associated with cognitive phenotypes. However, it is unclear how GRIN2B genetic variation affects gene expression and prefrontal cognitive processing. Using a composite score, we tested the combined effect of GRIN2B variants on prefrontal activity during WM performance in healthy subjects.
  
  
  METHODS
  We computed a composite score to combine the effects of single nucleotide polymorphisms on post-mortem prefrontal GRIN2B mRNA expression. We then computed the composite score in independent samples of healthy participants in a peripheral blood expression study (n = 46), in a WM behavioural study (n = 116) and in a WM functional magnetic resonance imaging study (n = 122).
  
  
  RESULTS
  Five polymorphisms were associated with GRIN2B expression: rs2160517, rs219931, rs11055792, rs17833967 and rs12814951 (all corrected p < 0.05). The score computed to account for their combined effect reliably indexed gene expression. GRIN2B composite score correlated negatively with intelligence quotient, WM behavioural efficiency and dorsolateral prefrontal cortex activity. Moreover, there was a non-linear association between GRIN2B genetic score and prefrontal activity, i.e. both high and low putative genetic score levels were associated with high blood oxygen level-dependent signals in the prefrontal cortex.
  
  
  CONCLUSIONS
  Multiple genetic variants in GRIN2B are jointly associated with gene expression, prefrontal function and behaviour during WM. These results support the role of GRIN2B genetic variants in WM prefrontal activity in human adults.
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pergola
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: P
authors.initials: P
authors.lastname: Di Carlo
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: I
authors.initials: I
authors.lastname: Andriola
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: B
authors.initials: B
authors.lastname: Gelao
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: S
authors.initials: S
authors.lastname: Torretta
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: M T
authors.initials: MT
authors.lastname: Attrotto
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: L
authors.initials: L
authors.lastname: Fazio
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: A
authors.initials: A
authors.lastname: Raio
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: D
authors.initials: D
authors.lastname: Albergo
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: R
authors.initials: R
authors.lastname: Masellis
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: A
authors.initials: A
authors.lastname: Rampino
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: G
authors.initials: G
authors.lastname: Blasi
authors.affiliation: Department of Basic Medical Sciences,Neuroscience and Sensory Organs,University of Bari 'Aldo Moro',Piazza Giulio Cesare 11,70124 Bari,Italy.
authors.forename: A
authors.initials: A
authors.lastname: Bertolino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D017397:Prefrontal Cortex / Q000503:physiopathology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics*; D055815:Young Adult
chemical_list: C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate
keywords: Expression quantitative trait loci; GRIN2B; N-methyl-d-aspartate; prefrontal cortex; working memory