Preserved hippocampus activation in normal aging as revealed by fMRI. Hippocampus

Department of Psychology, Stockholm University, Sweden.
Hippocampus (Impact Factor: 4.16). 07/2011; 21(7):753-66. DOI: 10.1002/hipo.20794
Source: PubMed


The hippocampus is deteriorated in various pathologies such as Alzheimer's disease (AD) and such deterioration has been linked to memory impairment. By contrast, the structural and functional effects of normal aging on the hippocampus is a matter of debate, with some findings suggesting deterioration and others providing evidence of preservation. This constitutes a crucial question since many investigations on AD are based on the assumption that the deterioration of the hippocampus is the breaking point between normal and pathological aging. A growing number of fMRI studies specifically aimed at investigating hippocampal engagement in various cognitive tasks, notably memory tasks, but the results have been inconclusive. Here, we optimized the episodic face-name paired-associates task in order to test the functioning of the hippocampus in normal aging. Critically, we found no difference in the activation of the hippocampus between the young and a group of older participants. Analysis of individual patterns of activation substantiated this impression. Collectively, these findings provide evidence of preserved hippocampal functioning in normal aging.

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Available from: Jonas Persson, Oct 09, 2015
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    • "Most notable was age-related decline in the hippocampus — a region more anterior than the posterior hippocampal activity that showed ageinvariant effects. Age-related decline in hippocampal activity is sometimes (e.g., Daselaar et al., 2006; Dennis and Cabeza, 2008; Giovanello et al., 2010), but not always associated with reduced recollection in aging (e.g., Angel et al., 2013; Dulas and Duarte, 2012; Duverne et al., 2008; Persson et al., 2011). In the present study, the different age effects found in the more anterior hippocampal region might be related to an anterior-to-posterior volume loss that has recently been associated with advanced age (e.g., Gordon et al., 2012), as well as the finding that anterior hippocampus might be more sensitive to age-related functional declines, although the literature is somewhat mixed in this regard (see Ta et al., 2012). "
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    ABSTRACT: Episodic memory decline is a hallmark of normal cognitive aging. Here, we report the first event-related fMRI study to directly investigate age differences in the neural reactivation of qualitatively rich perceptual details during recollection. Younger and older adults studied pictures of complex scenes at different presentation durations along with descriptive verbal labels, and these labels subsequently were used during fMRI scanning to cue picture recollections of varying perceptual detail. As expected from prior behavioral work, the two groups subjectively rated their recollections as containing similar amounts of perceptual detail, despite objectively measured recollection impairment in older adults. In both age groups, comparisons of retrieval trials that varied in recollected detail revealed robust activity in brain regions previously linked to recollection, including hippocampus and both medial and lateral regions of the prefrontal and posterior parietal cortex. Critically, this analysis also revealed recollection-related activity in visual processing regions that were active in an independent picture-perception task, and these regions showed age-related reductions in activity during recollection that cannot be attributed to age differences in response criteria. These fMRI findings provide new evidence that aging reduces the absolute quantity of perceptual details that are reactivated from memory, and they help to explain why aging reduces the reliability of subjective memory judgments.
    NeuroImage 05/2014; 98. DOI:10.1016/j.neuroimage.2014.05.012 · 6.36 Impact Factor
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    • "One possible way to directly examine the functional age-related changes is by employing taskactivated fMRI. A recent study [Persson et al., 2010] applied an episodic face-name paired-associates task during fMRI to 16 young and 20 older subjects, but found no difference in the activation of the hippocampus between the groups. However, the authors noted that the null finding could be due to weak statistical power. "
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    ABSTRACT: Evidence for an anterior-posterior gradient of age-related volume reduction along the hippocampal longitudinal axis has been reported in normal aging, but functional changes have yet to be systematically investigated. The current study applied an advanced brain mapping technique, large deformation diffeomorphic metric mapping (LDDMM), automatically delineating the hippocampus into the anterior and posterior segments based on anatomical landmarks. We studied this anterior-posterior gradient in terms of structural and functional MRI in 66 participants aged from 19 to 79 years. The results showed age-related structural volume reduction in both anterior and posterior hippocampi, with greater tendency for anterior decrease. FMRI task contrasts that robustly activated the anterior (associative/relational processing) and posterior (novelty) hippocampus independently, showed only significant reduction of activation in the anterior hippocampus as age increased. Our results revealed positive correlation between structural atrophy and functional decrease in the anterior hippocampi, regardless of task performance in normal aging. These findings suggest that anatomy and functions related to the anterior hippocampus may be more vulnerable to aging, than previously thought. Hum Brain Mapp 33:2415-2427, 2012. © 2011 Wiley Periodicals, Inc.
    Human Brain Mapping 10/2012; 33(10):2415-27. DOI:10.1002/hbm.21364 · 5.97 Impact Factor
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    • "For example, age-equivalent BOLD signal has been observed in medial temporal lobe in numerous studies (e.g. Morcom et al. 2003; Persson et al. 2011), even in the presence of ΔCBF increases (Restom et al. 2007). Our results support the conclusion that these results are more a reflection of age-related increases in ΔCMRO2, minimized by the effects of increased ΔCBF, than age-equivalence in neural activity per se (cf. "
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    ABSTRACT: The precise mechanisms that give rise to the blood-oxygen-level-dependent (BOLD) activation differences that accompany age-related cognitive slowing remain fundamentally unknown. We sought to isolate the origin of age-related BOLD changes by comparing blood-flow and oxygen-metabolic constituents of the BOLD response using dual-echo arterial spin labeling during visual stimulation and CO(2) ingestion. We hypothesized, and our results confirmed, that age-related changes in the ratio of fractional cerebral blood flow to fractional cerebral metabolic rate of oxygen consumption (ΔCBF/ΔCMRO(2)) lead to the BOLD changes that are observed in older adults. ΔCBF/ΔCMRO(2) was also significantly related to performance, suggesting that age-related cognitive slowing results from neural cell assemblies that operate less efficiently, requiring greater oxygen metabolism that is not matched by blood-flow changes relative to younger adults. Age-related changes in ΔCBF/ΔCMRO(2) are sufficient to explain variations in BOLD responding and performance cited throughout the literature, assuming no bias based on physiological baseline CMRO(2).
    Cerebral Cortex 08/2012; 23(10). DOI:10.1093/cercor/bhs233 · 8.67 Impact Factor
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