PMID- 30342274
OWN - NLM
STAT- MEDLINE
DCOM- 20191219
LR  - 20191219
IS  - 1558-1497 (Electronic)
IS  - 0197-4580 (Linking)
VI  - 73
DP  - 2019 Jan
TI  - Impaired perceptual integration and memory for unitized representations are 
      associated with perirhinal cortex atrophy in Alzheimer's disease.
PG  - 135-144
LID - S0197-4580(18)30346-4 [pii]
LID - 10.1016/j.neurobiolaging.2018.09.021 [doi]
AB  - Unitization, the capacity to encode associations as one integrated entity, can 
      enhance associative memory in populations with an associative memory deficit by 
      promoting familiarity-based associative recognition. Patients with Alzheimer's 
      disease (AD) are typically impaired in associative memory compared with healthy 
      controls but do not benefit from unitization strategies. Using fragmented 
      pictures of objects, this study aimed at assessing which of the cognitive 
      processes that compose unitization is actually affected in AD: the retrieval of 
      unitized representations itself, or some earlier stages of processing, such as 
      the integration process at a perceptual or conceptual stage of representation. We 
      also intended to relate patients' object unitization capacity to the integrity of 
      their perirhinal cortex (PrC), as the PrC is thought to underlie unitization and 
      is also one of the first affected regions in AD. We evaluated perceptual 
      integration capacity and subsequent memory for those items that have supposedly 
      been unitized in 23 mild AD patients and 20 controls. We systematically 
      manipulated the level of perceptual integration during encoding by presenting 
      object pictures that were either left intact, separated into 2 fragments, or 
      separated into 4 fragments. Subjects were instructed to unitize the fragments 
      into a single representation. Success of integration was assessed by a question 
      requiring the identification of the object. Participants also underwent a 
      structural magnetic resonance imaging examination, and measures of PrC, posterior 
      cingulate cortex volume and thickness, and hippocampal volume, were extracted. 
      The results showed that patients' perceptual integration performance decreased 
      with the increased fragmentation level and that their memory for unitized 
      representations was impaired whatever the demands in terms of perceptual 
      integration at encoding. Both perceptual integration and memory for unitized 
      representations were related to the integrity of the PrC, and memory for unitized 
      representations was also related to the volume of the hippocampus. We argue that, 
      globally, this supports representational theories of memory that hold that the 
      role of the PrC is not only perceptual nor mnemonic but instead underlies complex 
      object representation.
CI  - Copyright (c) 2018 Elsevier Inc. All rights reserved.
FAU - Delhaye, Emma
AU  - Delhaye E
AD  - GIGA-CRC In-Vivo Imaging, University in Liege, Liege, Belgium; PsyNCog, Faculty 
      of Psychology, University in Liege, Liege, Belgium. Electronic address: 
      emma.delhaye@uliege.be.
FAU - Bahri, Mohamed Ali
AU  - Bahri MA
AD  - GIGA-CRC In-Vivo Imaging, University in Liege, Liege, Belgium.
FAU - Salmon, Eric
AU  - Salmon E
AD  - GIGA-CRC In-Vivo Imaging, University in Liege, Liege, Belgium; PsyNCog, Faculty 
      of Psychology, University in Liege, Liege, Belgium; Memory Clinic, CHU Liege, 
      University in Liege, Liege, Belgium.
FAU - Bastin, Christine
AU  - Bastin C
AD  - GIGA-CRC In-Vivo Imaging, University in Liege, Liege, Belgium; PsyNCog, Faculty 
      of Psychology, University in Liege, Liege, Belgium.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20180922
PL  - United States
TA  - Neurobiol Aging
JT  - Neurobiology of aging
JID - 8100437
SB  - IM
MH  - Aged
MH  - Aged, 80 and over
MH  - Alzheimer Disease/diagnostic imaging/*pathology/*psychology
MH  - *Cognition
MH  - Female
MH  - Humans
MH  - Magnetic Resonance Imaging
MH  - Male
MH  - *Memory
MH  - Neuroimaging
MH  - *Perception
MH  - Perirhinal Cortex/diagnostic imaging/drug effects/*pathology
OTO - NOTNLM
OT  - Alzheimer's disease
OT  - Perirhinal cortex
OT  - Unitization
EDAT- 2018/10/21 06:00
MHDA- 2019/12/20 06:00
CRDT- 2018/10/21 06:00
PHST- 2018/02/09 00:00 [received]
PHST- 2018/09/12 00:00 [revised]
PHST- 2018/09/15 00:00 [accepted]
PHST- 2018/10/21 06:00 [pubmed]
PHST- 2019/12/20 06:00 [medline]
PHST- 2018/10/21 06:00 [entrez]
AID - S0197-4580(18)30346-4 [pii]
AID - 10.1016/j.neurobiolaging.2018.09.021 [doi]
PST - ppublish
SO  - Neurobiol Aging. 2019 Jan;73:135-144. doi: 10.1016/j.neurobiolaging.2018.09.021. 
      Epub 2018 Sep 22.