title: Differential prefrontal and subcortical circuitry engagement during encoding of semantically related words in patients with late-life depression.
abstract: OBJECTIVE
  Verbal memory difficulties are common among individuals with late-life depression (LLD), though there is limited knowledge about disruptions to underlying cerebral circuitry. The purpose of this study is to examine aberrations to cerebral networks implicated in encoding novel verbal semantic material among older adults with LLD.
  
  
  METHODS
  Twenty-four older adults with early-onset LLD and 23 non-depressed comparisons participated in the study. Participants completed a word list-learning task while undergoing functional magnetic resonance imaging.
  
  
  RESULTS
  In the context of equivalent recall and recognition of words following scanning and similar hippocampal volumes, patients with LLD exhibited less activation in structures known to be relevant for new learning and memory, including hippocampus, parahippocampal gyrus, insula, and cingulate, relative to non-ill comparisons. An important region in which the LLD group displayed greater activation than the non-depressed comparison group was in left inferior frontal gyrus, an area involved in cognitive control and controlled semantic/phonological retrieval and analysis; this region may be critical for LLD patients to consolidate encoded words into memory.
  
  
  CONCLUSIONS
  Functional irregularities found in LLD patients may reflect different modes of processing to-be-remembered information and/or early changes predictive of incipient cognitive decline. Future studies might consider mechanisms that could contribute to these functional differences, including hypothalamic-pituitary-adrenal axis functioning and vascular integrity, and utilize longitudinal designs in order to understand whether functional changes are predictive of incipient cognitive decline.
authors.affiliation: Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA; Research and Development, Jesse Brown VA Medical Center, Chicago, IL, USA.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Weisenbach
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Kassel
authors.forename: Julia
authors.initials: J
authors.lastname: Rao
authors.forename: Annie L
authors.initials: AL
authors.lastname: Weldon
authors.forename: Erich T
authors.initials: ET
authors.lastname: Avery
authors.forename: Emily M
authors.initials: EM
authors.lastname: Briceno
authors.forename: Olusola
authors.initials: O
authors.lastname: Ajilore
authors.forename: Megan
authors.initials: M
authors.lastname: Mann
authors.forename: Helen C
authors.initials: HC
authors.lastname: Kales
authors.forename: Robert C
authors.initials: RC
authors.lastname: Welsh
authors.forename: Jon-Kar
authors.initials: JK
authors.lastname: Zubieta
authors.forename: Scott A
authors.initials: SA
authors.lastname: Langenecker
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000502:physiology*; D003866:Depressive Disorder / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D012660:Semantics; D014706:Verbal Learning / Q000502:physiology*
keywords: aging; depression; hippocampus; memory