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Posterior compensatory network in cognitively intact elders with hippocampal atrophy
Author(s) -
Valenzuela Michael J.,
Turner Andrew J.F.,
Kochan Nicole A.,
Wen Wei,
Suo Chao,
Hallock Harry,
McIntosh Randy A.,
Sachdev Perminder,
Breakspear Michael
Publication year - 2015
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.22395
Subject(s) - hippocampal formation , atrophy , psychology , neuroscience , hippocampus , working memory , cognition , spatial memory , population , cognitive psychology , posterior cortical atrophy , posterior parietal cortex , medicine , dementia , pathology , disease , environmental health
Functional compensation in late life is poorly understood but may be vital to understanding long‐term cognitive trajectories. To study this we first established an empirically derived threshold to distinguish hippocampal atrophy in those with Mild Cognitive Impairment (MCI n = 34) from those with proficient cognition (PRO n = 22), using data from a population‐based cohort. Next, to identify compensatory networks we compared cortical activity patterns during a graded spatial working memory (SWM) task in only cognitively proficient individuals, either with (PRO ATR ) or without hippocampal atrophy (PRO NIL ). Multivariate Partial Least Squares analyses revealed that these groups engaged spatially distinct SWM‐related networks. In those with hippocampal atrophy and under conditions of basic‐SWM demand, expression of a posterior compensatory network (PCN) comprised calcarine and posterior parietal cortex strongly correlated with superior SWM performance ( r = −0.96). In these individuals, basic level SWM response times were faster and no less accurate than in those with no hippocampal atrophy. Cognitively proficient older individuals with hippocampal atrophy may, therefore, uniquely engage posterior brain areas when performing simple spatial working memory tasks. © 2014 Wiley Periodicals, Inc.