Semantic retrieval over time in the aging brain: Structural evidence of hippocampal contribution.
Hippocampus. 2015-03-25; 25(9): 1008-1016
DOI: 10.1002/hipo.22423
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1. Hippocampus. 2015 Sep;25(9):1008-16. doi: 10.1002/hipo.22423. Epub 2015 Mar 25.
Semantic retrieval over time in the aging brain: Structural evidence of
hippocampal contribution.
Catheline G(1)(2)(3), Amieva H(4)(5), Dilharreguy B(1)(2), Bernard C(1), Duperron
MG(1), Helmer C(4)(5), Dartigues JF(4)(5), Allard M(1)(2)(3)(6).
Author information:
(1)Univ. Bordeaux, INCIA, UMR 5287, Talence, France.
(2)CNRS, INCIA, UMR 5287, Talence, France.
(3)EPHE, Paris, France.
(4)ISPED, Université de Bordeaux, Bordeaux, France.
(5)Centre de Recherche Inserm U897, Bordeaux, France.
(6)Chu de Bordeaux, France.
This study investigates relationship between regional cerebral volumes and
performances over time of a categorical fluency task, in a sample of older adults
(n = 316). Using voxel-wise technique, the relationship between local grey matter
volume and Isaacs Set Test (IST) scores at its early (first 15 sec) and late
(last 15 sec) phase production was analyzed with a linear regression model
adjusting for age, sex, educational level, ApoEɛ4 allele, handedness and Grey
Matter atrophy. Lower early IST scores were associated with smaller volumes in
bilateral inferior frontal gyri and in right thalamus, whereas lower late IST
scores were associated to smaller left inferior parietal gyrus and left anterior
hippocampus. An analysis based on automatic segmentation of hippocampus confirmed
the latest relationship which cannot be attributed to the correlation of each
variable with global cognitive impairment because it remained when MMSE was
accounted for. We observed a switch from frontal to temporo-parietal regions as
words retrieval become more difficult over time. Automatic speech production of
the early phase of the category fluency task is dependent on executive networks
integrity whereas controlled speech production of the late phase is dependent on
memory networks integrity, including left hippocampus. These results are
concordant with recent imaging studies expanding the implication of hippocampus
to semantic memory performances and they underlie the need to consider verbal
fluency task over time.
© 2015 Wiley Periodicals, Inc.
DOI: 10.1002/hipo.22423
PMID: 25614980 [Indexed for MEDLINE]