title: 3T hippocampal glutamate-glutamine complex reflects verbal memory decline in aging.
abstract: The hippocampus is a critical site for alterations that are responsible for age-related changes in memory. Here, we present a relatively novel approach of examining the relationship between memory performance and glutamate-glutamine levels using short echo time magnetic resonance spectroscopy. Specifically, we investigated the relationship between Glx (a composite of glutamate and glutamine) levels in the hippocampus, performance on a word-recall task, and resting-state functional connectivity. While there was no overall difference in Glx intensity between young and aging adults, we identified a positive correlation between delayed word-list recall and Glx, bilaterally in older adults, but not in young adults. Collapsed across age, we also discovered a negative relationship between Glx intensity and resting-state functional connectivity between the anterior hippocampus and regions in the subcallosal gyrus. These findings demonstrate the possible utility of Glx in identifying age-related changes in the brain and behavior and provide encouragement that magnetic resonance spectroscopy can be useful in predicting age-related decline before any physical abnormalities are present.
authors.affiliation: Department of Neurobiology and Behavior, University of California, Irvine, CA, USA; Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, USA.
authors.forename: Simona
authors.initials: S
authors.lastname: Nikolova
authors.affiliation: Department of Neurobiology and Behavior, University of California, Irvine, CA, USA; Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, USA.
authors.forename: Shauna M
authors.initials: SM
authors.lastname: Stark
authors.affiliation: Department of Neurobiology and Behavior, University of California, Irvine, CA, USA; Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, USA. Electronic address: cestark@uci.edu.
authors.forename: Craig E L
authors.initials: CEL
authors.lastname: Stark
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism* / Q000523:psychology*; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D006624:Hippocampus / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000209:etiology* / Q000378:metabolism / Q000523:psychology*; D014705:Verbal Behavior / Q000502:physiology*
chemical_list: D005973:Glutamine; D018698:Glutamic Acid
keywords: 3T MRI; Aging; Glx; Imaging; MRS; Memory