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@PHDTHESIS{Plachti:889994,
      author       = {Plachti, Anna},
      title        = {{M}ultimodal {M}apping of the {H}ippocampus across the
                      lifespan and in dementia},
      school       = {HHU Düsseldorf},
      type         = {Dissertation},
      reportid     = {FZJ-2021-00588},
      pages        = {174},
      year         = {2020},
      note         = {Dissertation, HHU Düsseldorf, 2020},
      abstract     = {The hippocampus is associated with behaviors such as memory
                      and navigation, and is one ofthe first brain regions to be
                      affected in diseases such as Alzheimer's dementia,
                      depression andanxiety disorders. Patients who have undergone
                      hippocampal resection experience greatdifficulties in
                      everyday life and suffer from anterograde and retrograde
                      amnesia.Understanding how the hippocampus is organized and
                      what behaviors are associated with it,is therefore of utmost
                      importance. The mapping of the hippocampus, i.e. the
                      description of itsorganization, has so far been limited to
                      the cellular level. However, a description of
                      theorganization of the hippocampus at the level of
                      large-scale networks is missing, which may bemore important
                      for drawing conclusions about behavior than the cellular
                      organization.With the use of imaging techniques and the
                      method of "Connectivity-Based Parcellation", it ispossible
                      to create in-vivo maps of the hippocampus across a large
                      number of participants. Themethod of Connectivity-Based
                      Parcellation divides the hippocampus into subregions
                      thatdiffer particularly strongly in their connectivity
                      profiles and display therefore a specificdifferentiation
                      pattern. The present work thus aimed at mapping the
                      hippocampus on the basisof functional connectivity and
                      structural covariance. Functional connectivity was
                      eithercalculated meta-analytically across tasks of published
                      functional studies or measured underresting state conditions
                      with the magnetic resonance tomography. Structural
                      covariance is arelatively new measure that estimates the
                      co-variation in grey matter intensities acrossindividuals
                      and thus maps co-plasticity and co-atrophy as brain regions
                      grow or degeneratetogether.In addition to mapping the
                      hippocampus, I was also strongly interested in
                      investigatingwhether differentiation patterns within the
                      hippocampus change over the course of life and indementia
                      and whether they can be distinguished from each other.
                      Therefore changes inhippocampal organization based on
                      alterations in structural covariance networks were
                      studied.The investigations were carried out on hundreds of
                      functional and structural imaging datafrom open accessible
                      databases. In contrast to the cytoarchitectonic
                      organization, theorganization of the hippocampus based on
                      functional connectivity showed a differentiationalong the
                      anterior-posterior axis with a subdivision into an anterior,
                      middle and posteriorsubregion. In contrast, the organization
                      based on structural covariance showed a
                      mediallateraldifferentiation into an anterior, medial and
                      lateral subregion similar to thedifferentiation into cornu
                      ammonis and subiculum.8Age-related changes were mainly found
                      in the posterior region of the hippocampus, where thelateral
                      subregion decreased. However, the hippocampal
                      differentiation pattern in dementiaclosely resembled a
                      functional division along the anterior-posterior axis, as
                      the lateralsubregion extended strongly in the medial
                      direction and covered almost the entirehippocampal body.
                      These changes were interpreted as a possible indication that
                      in dementiafunctional networks are particularly affected by
                      the spread of pathogens such asneurofibrillary tangles and
                      amyloid beta plaques and have therefore a long-term effect
                      on theco-atrophy of the hippocampus.To understand in which
                      behaviors the hippocampus is involved, I characterized both
                      thesubregions and the associated networks behaviorally using
                      databases that archive thousandsof activation studies. The
                      results suggested that the anterior hippocampus is more
                      involved inself-centric information processing and the
                      posterior hippocampus more involved in
                      worldcentericinformation processing. In addition, it can be
                      assumed that based on the networks ofstructural covariance,
                      the medial subregion has something to do with visual-motor
                      processing.The present work therefore showed that the
                      hippocampus has both an anterior-posterior and
                      amedial-lateral organization, depending on the type of
                      networks, whether functional orstructural. Structural
                      networks are not stable over the lifespan but change with
                      age anddementia mirroring different underlying processes.},
      cin          = {INM-7},
      cid          = {I:(DE-Juel1)INM-7-20090406},
      pnm          = {572 - (Dys-)function and Plasticity (POF3-572)},
      pid          = {G:(DE-HGF)POF3-572},
      typ          = {PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/889994},
}