title: Fornix Microstructure and Memory Performance Is Associated with Altered Neural Connectivity during Episodic Recognition.
abstract: OBJECTIVE
  The purpose of this study was to assess whether age-related differences in white matter microstructure are associated with altered task-related connectivity during episodic recognition.
  
  
  METHODS
  Using functional magnetic resonance imaging and diffusion tensor imaging from 282 cognitively healthy middle-to-late aged adults enrolled in the Wisconsin Registry for Alzheimer's Prevention, we investigated whether fractional anisotropy (FA) within white matter regions known to decline with age was associated with task-related connectivity within the recognition network.
  
  
  RESULTS
  There was a positive relationship between fornix FA and memory performance, both of which negatively correlated with age. Psychophysiological interaction analyses revealed that higher fornix FA was associated with increased task-related connectivity amongst the hippocampus, caudate, precuneus, middle occipital gyrus, and middle frontal gyrus. In addition, better task performance was associated with increased task-related connectivity between the posterior cingulate gyrus, middle frontal gyrus, cuneus, and hippocampus.
  
  
  CONCLUSIONS
  The findings indicate that age has a negative effect on white matter microstructure, which in turn has a negative impact on memory performance. However, fornix microstructure did not significantly mediate the effect of age on performance. Of interest, dynamic functional connectivity was associated with better memory performance. The results of the psychophysiological interaction analysis further revealed that alterations in fornix microstructure explain-at least in part-connectivity among cortical regions in the recognition memory network. Our results may further elucidate the relationship between structural connectivity, neural function, and cognition.
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Martina
authors.initials: M
authors.lastname: Ly
authors.affiliation: 5Waisman Laboratory for Brain Imaging and Behavior,University of Wisconsin,Madison,Wisconsin.
authors.forename: Nagesh
authors.initials: N
authors.lastname: Adluru
authors.affiliation: 5Waisman Laboratory for Brain Imaging and Behavior,University of Wisconsin,Madison,Wisconsin.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Destiche
authors.affiliation: 5Waisman Laboratory for Brain Imaging and Behavior,University of Wisconsin,Madison,Wisconsin.
authors.forename: Sharon Y
authors.initials: SY
authors.lastname: Lu
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Oh
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Siobhan M
authors.initials: SM
authors.lastname: Hoscheidt
authors.affiliation: 5Waisman Laboratory for Brain Imaging and Behavior,University of Wisconsin,Madison,Wisconsin.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Alexander
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Ozioma C
authors.initials: OC
authors.lastname: Okonkwo
authors.affiliation: 2Alzheimer's Disease Research Center,University of Wisconsin School of Medicine and Public Health,Madison,Wisconsin.
authors.forename: Howard A
authors.initials: HA
authors.lastname: Rowley
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sager
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Sterling C
authors.initials: SC
authors.lastname: Johnson
authors.affiliation: 1Geriatric Research Education and Clinical Center,William S. Middleton Memorial Veteran's Hospital,Madison,Wisconsin.
authors.forename: Barbara B
authors.initials: BB
authors.lastname: Bendlin
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000502:physiology*; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D021641:Recognition, Psychology / Q000502:physiology*; D013223:Statistics as Topic; D066127:White Matter / Q000000981:diagnostic imaging / Q000502:physiology
keywords: Aging; Episodic recognition; Fractional anisotropy; Task-related functional connectivity; fMRI; gPPI