Longitudinal Changes in the Cerebral Cortex Functional Organization of Healthy Elderly

Chong, Joanna Su Xian; Ng, Kwun Kei; Tandi, Jesisca; Wang, Chenhao; Poh, Jia-Hou; Lo, June C.; Chee, Michael W.L.; Zhou, Juan

doi:10.1523/jneurosci.1451-18.2019

Cited by 88 publications

(121 citation statements)

References 86 publications

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“…Community detection at both stages was performed using a range of γ parameters from 1 to 6 (resolution parameter γ determines the number of communities detected). We reported findings using individual-level γ = 3 and group-level γ = 2, as the brain network communities derived from the HC group with these two parameters best reflected the normative network organizations described in previous literature [ 24 , 26 , 115 ].…”

Section: Methodsmentioning

confidence: 61%

Distinct network topology in Alzheimer’s disease and behavioral variant frontotemporal dementia

Wang

et al. 2021

Alz Res Therapy

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Background Alzheimer’s disease (AD) and behavioral variant frontotemporal dementia (bvFTD) cause distinct atrophy and functional disruptions within two major intrinsic brain networks, namely the default network and the salience network, respectively. It remains unclear if inter-network relationships and whole-brain network topology are also altered and underpin cognitive and social–emotional functional deficits. Methods In total, 111 participants (50 AD, 14 bvFTD, and 47 age- and gender-matched healthy controls) underwent resting-state functional magnetic resonance imaging (fMRI) and neuropsychological assessments. Functional connectivity was derived among 144 brain regions of interest. Graph theoretical analysis was applied to characterize network integration, segregation, and module distinctiveness (degree centrality, nodal efficiency, within-module degree, and participation coefficient) in AD, bvFTD, and healthy participants. Group differences in graph theoretical measures and empirically derived network community structures, as well as the associations between these indices and cognitive performance and neuropsychiatric symptoms, were subject to general linear models, with age, gender, education, motion, and scanner type controlled. Results Our results suggested that AD had lower integration in the default and control networks, while bvFTD exhibited disrupted integration in the salience network. Interestingly, AD and bvFTD had the highest and lowest degree of integration in the thalamus, respectively. Such divergence in topological aberration was recapitulated in network segregation and module distinctiveness loss, with AD showing poorer modular structure between the default and control networks, and bvFTD having more fragmented modules in the salience network and subcortical regions. Importantly, aberrations in network topology were related to worse attention deficits and greater severity in neuropsychiatric symptoms across syndromes. Conclusions Our findings underscore the reciprocal relationships between the default, control, and salience networks that may account for the cognitive decline and neuropsychiatric symptoms in dementia.

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Section: Methodsmentioning

confidence: 61%

Distinct network topology in Alzheimer’s disease and behavioral variant frontotemporal dementia

Wang

et al. 2021

Alz Res Therapy

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“…Therefore, we proposed that older adults establish a compensatory mechanism for processing high-level cognitive semantic audio-visual stimuli, and the enhanced AVI effect was an adaptation of the ageing brain to compensate for unimodal functional decline. Furthermore, accompanying sensory process declines, reduced differentiation abilities, and regional process specificity of the ageing brain have also been extensively reported (Chong et al, 2019;Grady, 2012). Wang et al (2018) investigated age-related functional connectivity in audio-visual temporal asynchrony integration tasks, and their results illustrated that the functional connectivity and network efficiencies of older adults revealed higher global and local efficiencies in both the theta and alpha bands.…”

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Stimulus Specific to Age-Related Audio-Visual Integration in Discrimination Tasks

Ren

Xu²,

et al. 2020

i-Perception

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Age-related audio-visual integration (AVI) has been investigated extensively; however, AVI ability is either enhanced or reduced with ageing, and this matter is still controversial because of the lack of systematic investigations. To remove possible variates, 26 older adults and 26 younger adults were recruited to conduct meaningless and semantic audio-visual discrimination tasks to assess the ageing effect of AVI systematically. The results for the mean response times showed a significantly faster response to the audio-visual (AV) target than that to the auditory (A) or visual (V) target and a significantly faster response to all targets by the younger adults than that by the older adults (A, V, and AV) in all conditions. In addition, a further comparison of the differences between the probability of audio-visual cumulative distributive functions (CDFs) and race model CDFs showed delayed AVI effects and a longer time window for AVI in older adults than that in younger adults in all conditions. The AVI effect was lower in older adults than that in younger adults during simple meaningless image discrimination (63.0 ms vs. 108.8 ms), but the findings were inverse during semantic image discrimination (310.3 ms vs. 127.2 ms). In addition, there was no significant difference between older and younger adults during semantic character discrimination (98.1 ms vs. 117.2 ms). These results suggested that AVI ability was impaired in older adults, but a compensatory mechanism was established for processing sematic audio-visual stimuli.

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“…While it is possible that all of the patients in Phenotype 4 are undergoing AD-like changes, it is more likely that this pattern is in fact representative of baseline age-related cognitive changes. A recent study comparing young versus older adult connectomes showed declines in the functionality of this same dorsal prefrontal-attention axis even in healthy elderly patients while executive, orientation, visuospatial, and language areas were spared 27 . The prevalence of Phenotype 4 suggests that it is a common degenerative pathway in all of this study's patients, including the cognitively normal ones.…”

Section: Discussionmentioning

confidence: 92%

Multimodal Phenotyping of Alzheimer’s Disease with Longitudinal Magnetic Resonance Imaging and Cognitive Function Data

Kim

Jiang

Giancardo

et al. 2020

Sci Rep

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's Disease neuroimaging initiative † Alzheimer's disease (AD) varies a great deal cognitively regarding symptoms, test findings, the rate of progression, and neuroradiologically in terms of atrophy on magnetic resonance imaging (MRi). We hypothesized that an unbiased analysis of the progression of AD, regarding clinical and MRi features, will reveal a number of AD phenotypes. our objective is to develop and use a computational method for multi-modal analysis of changes in cognitive scores and MRi volumes to test for there being multiple AD phenotypes. In this retrospective cohort study with a total of 857 subjects from the AD (n = 213), Mci (n = 322), and control (CN, n = 322) groups, we used structural MRI data and neuropsychological assessments to develop a novel computational phenotyping method that groups brain regions from MRi and subsets of neuropsychological assessments in a non-biased fashion. the phenotyping method was built based on coupled nonnegative matrix factorization (c-nMf). As a result, the computational phenotyping method found four phenotypes with different combination and progression of neuropsychologic and neuroradiologic features. identifying distinct AD phenotypes here could help explain why only a subset of AD patients typically respond to any single treatment. this, in turn, will help us target treatments more specifically to certain responsive phenotypes. Alzheimer's disease (AD) is the most common form of dementia. It is a progressive neurodegenerative disorder associated with cognitive decline and atrophy seen on Magnetic Resonance Imaging (MRI) of the brain 1. It has become a major public health concern because of its increasing prevalence, chronicity, caregiver burden, and high personal and financial costs of care 2. AD is clinically very heterogeneous, varying between patients in terms of cognitive symptoms, test findings, and rates of progression 3. It also varies neuroradiologically in terms of atrophy on MRI Memory deficits, caused by pathological changes in structures of the medial temporal lobe 4,5 , are typically regarded as the earliest and most salient symptom of AD 6,7 , but this is not invariably the case 8. Instead, patients may present with visuospatial or language disturbance, or apraxia 9 , likely reflecting regional differences in the underlying neuropathology 8,10-12. It can also present as a single area of cognitive impairment without a change in activities of daily living, in which case this prodromal AD is referred to as mild cognitive impairment, or MCI. Several recent treatment trials for AD have shown efficacy in a subset of patients, but not all patients. We hypothesize that there are subsets of AD patients who respond differently to treatments. Furthermore, we

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Longitudinal Changes in the Cerebral Cortex Functional Organization of Healthy Elderly

Cited by 88 publications

References 86 publications

Distinct network topology in Alzheimer’s disease and behavioral variant frontotemporal dementia

Distinct network topology in Alzheimer’s disease and behavioral variant frontotemporal dementia

Stimulus Specific to Age-Related Audio-Visual Integration in Discrimination Tasks

Multimodal Phenotyping of Alzheimer’s Disease with Longitudinal Magnetic Resonance Imaging and Cognitive Function Data

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