Memory and executive function in older adults: Relationships with temporal and prefrontal gray matter volumes and white matter hyperintensities

Department of Psychology, University of Arizona, Tucson, AZ 85721, USA.
Neuropsychologia (Impact Factor: 3.3). 02/2004; 42(10):1313-35. DOI: 10.1016/j.neuropsychologia.2004.02.009
Source: PubMed


Forty-eight healthy adults aged 65-85 were recruited for structural magnetic resonance scans after an extensive neuropsychological battery that ensured a high degree of variability across the sample in performance on long-term memory tests, and on tests traditionally thought to rely on prefrontal cortex. Gray matter volumes were measured for three gyri in the frontal lobe (superior, middle, inferior), six gyri in the temporal lobe (superior, middle, inferior, fusiform, parahippocampal, and hippocampus), and the occipital lobe. Gray matter volumes declined across the age range evaluated, but with substantial regional variation--greatest in the inferior frontal, superior temporal, and middle temporal gyri but negligible in the occipital lobe. Both memory performance and executive function declined as the number of hyperintense regions in the subcortical white matter increased. Memory performance was also significantly correlated with gray matter volumes of the middle frontal gyrus (MFG), and several regions of temporal neocortex. However, the correlations were all in the negative direction; better memory performance was associated with smaller volumes. Several previous reports of significant negative correlations between gray matter volumes and memory performance are described, so that the possible reasons for this surprising finding are discussed.

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Available from: Elizabeth L Glisky
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    • "Specifically, healthy older individuals have reduced cortical volume , increased white matter abnormalities (WMA) and functional over-or under-activation have all been documented in the PFC compared with young individuals (e.g., Cabeza, 2002; Raz et al., 2005; Sullivan and Pfefferbaum, 2006; Fjell et al., 2009; Head et al., 2009). These structural abnormalities are correlated with poorer executive performance (e.g., Nagahama et al., 1997; Gunning-Dixon and Raz, 2003; Van Petten et al., 2004; Raz et al., 2007; Cardenas et al., 2011). For example, increased WMA and smaller anterior cingulate cortex volume are associated with poorer performance on the Stroop test and fluid intelligence tasks (e.g., Raz et al., 2007; Elderkin-Thompson et al., 2008, but see Salthouse (2011)). "
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    ABSTRACT: Age is known to affect prefrontal brain structure and executive functioning in healthy older adults, patients with neurodegenerative conditions and TBI. Yet, no studies appear to have systematically investigated the effect of age on cognitive performance in patients with focal lesions. We investigated the effect of age on the cognitive performance of a large sample of tumour and stroke patients with focal unilateral, frontal (n=68), or non-frontal lesions (n=45) and healthy controls (n=52). We retrospectively reviewed their cross sectional cognitive and imaging data. In our frontal patients, age significantly predicted the magnitude of their impairment on two executive tests (Raven's Advanced Progressive Matrices, RAPM and the Stroop test) but not on nominal (Graded Naming Test, GNT) or perceptual (Incomplete Letters) task. In our non-frontal patients, age did not predict the magnitude of their impairment on the RAPM and GNT. Furthermore, the exacerbated executive impairment observed in our frontal patients manifested itself from middle age. We found that only age consistently predicted the exacerbated executive impairment. Lesions to specific frontal areas, or an increase in global brain atrophy or white matter abnormalities were not associated with this impairment. Our results are in line with the notion that the frontal cortex plays a critical role in aging to counteract cognitive and neuronal decline. We suggest that the combined effect of aging and frontal lesions impairs the frontal cortical systems by causing its computational power to fall below the threshold needed to complete executive tasks successfully.
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    • "The meta-analysis by Di et al. (2014), for example, suggests relative GM preservation in the bilateral parahippocampal gyrus, the amygdala, specific thalamus nuclei, and the cingulate gyrus, whereas other studies showed a shrinkage of the cingulate gyrus and the hippocampal area with advancing age (Good et al., 2001; Raji et al., 2012; Resnick et al., 2003; Tisserand et al., 2004). Moreover, there are sporadic reports about GM volume loss in the cerebellum, in temporal and parietal areas, as well as in the primary visual cortex (Chee et al., 2009; Good et al., 2001; Raz et al., 2005; Resnick et al., 2003; Van Petten et al., 2004). Taken together, aging particularly seems to be associated with GM volume loss in frontal and subcortical brain regions, whereas other cerebral areas appear to be less affected by age-related structural decline. "
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    ABSTRACT: Aging comes along with reduced gray matter (GM) volume in several cerebral areas and with cognitive performance decline in different cognitive domains. Moreover, regional GM volume is linked to specific cognitive sub processes in older adults. However, it remains unclear which regional changes in older individuals are directly associated with decreased cognitive performance. Moreover, most of the studies on this topic focused on hippocampal and prefrontal brain regions and their relation to memory and executive functioning. Interestingly, there are only a few studies that reported an association between striatal brain volume and cognitive performance. This is insofar surprising that striatal structures are (1) highly affected by age and (2) involved in different neural circuits that serve intact cognition. To address these issues, voxel-based morphometry (VBM) was used to analyze GM volume in 18 younger and 18 older adults. Moreover, several neuropsychological tests from different neuropsychological test batteries were applied to assess a broad range of cognitive domains. Older adults showed less GM volume than younger adults within frontal, striatal, and cerebellar brain regions. In the group of older adults, significant correlations were found between striatal GM volume and memory performance and between prefrontal/temporal GM volume and executive functioning. The only direct overlap between brain regions associated with regional atrophy and cognitive performance in older adults was found for the right caudate: Older adults showed reduced caudate volume relative to younger adults. Moreover, caudate volume was positively correlated with associative memory accuracy in older adults and older adults showed poorer performances than younger adults in the respective associative memory task. Taken together, the current findings indicate the relevance of the caudate for associative memory decline in the aging brain. Copyright © 2015. Published by Elsevier B.V.
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    • "We also considered that the level of cognitive function could conceivably influence the rate of change, but omitted this from the model because that relationship is currently uncertain (e.g., Gow et al. 2012; Salthouse 2013, 2012). Perhaps one simplification in the model is the treatment of cognitive function as an undifferentiated global construct, when in fact different domains of cognition may age differentially within and across individuals (Mungas et al. 2010; Van Petten et al. 2004). It is also important to recognize that, although at the group level longitudinal data will often be characterized by linear decline, there is considerable inter-individual variability and almost certainly, nonlinearity in individual trajectories (Boyle et al. 2013; Dixon and de Frias 2009). "
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