title: Altered hippocampal function in major depression despite intact structure and resting perfusion.
abstract: Hippocampal volume reductions in major depression have been frequently reported. However, evidence for functional abnormalities in the same region in depression has been less clear. We investigated hippocampal function in depression using functional magnetic resonance imaging (fMRI) and neuropsychological tasks tapping spatial memory function, with complementing measures of hippocampal volume and resting blood flow to aid interpretation.
  
  
  
  A total of 20 patients with major depressive disorder (MDD) and a matched group of 20 healthy individuals participated. Participants underwent multimodal magnetic resonance imaging (MRI): fMRI during a spatial memory task, and structural MRI and resting blood flow measurements of the hippocampal region using arterial spin labelling. An offline battery of neuropsychological tests, including several measures of spatial memory, was also completed.
  
  
  
  The fMRI analysis showed significant group differences in bilateral anterior regions of the hippocampus. While control participants showed task-dependent differences in blood oxygen level-dependent (BOLD) signal, depressed patients did not. No group differences were detected with regard to hippocampal volume or resting blood flow. Patients showed reduced performance in several offline neuropsychological measures. All group differences were independent of differences in hippocampal volume and hippocampal blood flow.
  
  
  
  Functional abnormalities of the hippocampus can be observed in patients with MDD even when the volume and resting perfusion in the same region appear normal. This suggests that changes in hippocampal function can be observed independently of structural abnormalities of the hippocampus in depression.
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: A
authors.initials: A
authors.lastname: Finkelmeyer
authors.affiliation: Aging Research Center, Karolinska Institute,Stockholm,Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Nilsson
authors.affiliation: Aberdeen Biomedical Imaging Centre, University of Aberdeen,Aberdeen,UK.
authors.forename: J
authors.initials: J
authors.lastname: He
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: L
authors.initials: L
authors.lastname: Stevens
authors.affiliation: Monash Alfred Psychiatry Research Centre, Monash University,Melbourne,VIC,Australia.
authors.forename: J J
authors.initials: JJ
authors.lastname: Maller
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Moss
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: S
authors.initials: S
authors.lastname: Small
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: P
authors.initials: P
authors.lastname: Gallagher
authors.affiliation: School of Psychology, University of East Anglia,Norwich,UK.
authors.forename: K
authors.initials: K
authors.lastname: Coventry
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: I N
authors.initials: IN
authors.lastname: Ferrier
authors.affiliation: Institute of Neuroscience, Newcastle University,Newcastle-upon-Tyne,UK.
authors.forename: R H
authors.initials: RH
authors.lastname: McAllister-Williams
mesh_terms: D000328:Adult; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D065852:Spatial Memory / Q000502:physiology*
keywords: Hippocampus; magnetic resonance imaging; major depressive disorder; spatial memory