scholarly journals Age related differences in reaction time components and diffusion properties of normal-appearing white matter in healthy adults

2015 ◽  
Vol 66 ◽  
pp. 246-258 ◽  
Author(s):  
Yiqin Yang ◽  
Andrew R. Bender ◽  
Naftali Raz
Keyword(s):  
Reaction Time ◽  
White Matter ◽  
Healthy Adults ◽  
Normal Appearing White Matter ◽  
Age Related ◽  
And Diffusion ◽  
Diffusion Properties

scholarly journals Brain Substrates of Time-Based Prospective Memory Decline in Aging: A Voxel-Based Morphometry and Diffusion Tensor Imaging Study

2020 ◽  
Vol 31 (1) ◽  
pp. 396-409
Author(s):  
Alexandrine Morand ◽  
Shailendra Segobin ◽  
Grégory Lecouvey ◽  
Julie Gonneaud ◽  
Francis Eustache ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Prospective Memory ◽  
Gray Matter ◽  
Diffusion Tensor ◽  
Imaging Study ◽  
Age Related ◽  
Young Subjects ◽  
Anterior Prefrontal Cortex ◽  
And Diffusion

Abstract Time-based prospective memory (TBPM) allows us to remember to perform intended actions at a specific time in the future. TBPM is sensitive to the effects of age, but the neural substrates of this decline are still poorly understood. The aim of the present study was thus to better characterize the brain substrates of the age-related decline in TBPM, focusing on macrostructural gray matter and microstructural white matter integrity. We administered a TBPM task to 22 healthy young (26 ± 5.2 years) and 23 older (63 ± 5.9 years) participants, who also underwent volumetric magnetic resonance imaging and diffusion tensor imaging scans. Neuroimaging analyses revealed lower gray matter volumes in several brain areas in older participants, but these did not correlate with TBPM performance. By contrast, an age-related decline in fractional anisotropy in several white-matter tracts connecting frontal and occipital regions did correlate with TBPM performance, whereas there was no significant correlation in healthy young subjects. According to the literature, these tracts are connected to the anterior prefrontal cortex and the thalamus, 2 structures involved in TBPM. These results confirm the view that a disconnection process occurs in aging and contributes to cognitive decline.

scholarly journals Altered White Matter Organization in the TUBB3 E410K Syndrome

2018 ◽  
Vol 29 (8) ◽  
pp. 3561-3576 ◽  
Author(s):  
P Ellen Grant ◽  
Kiho Im ◽  
Banu Ahtam ◽  
Cynthia T Laurentys ◽  
Wai-Man Chan ◽  
...  
Keyword(s):  
White Matter ◽  
De Novo ◽  
Neuropsychological Testing ◽  
Network Efficiency ◽  
Age Related ◽  
Bilateral Absence ◽  
Cortical Parcellation ◽  
Social Disabilities ◽  
And Diffusion ◽  
Language Network

Abstract Seven unrelated individuals (four pediatric, three adults) with the TUBB3 E410K syndrome, harboring identical de novo heterozygous TUBB3 c.1228 G>A mutations, underwent neuropsychological testing and neuroimaging. Despite the absence of cortical malformations, they have intellectual and social disabilities. To search for potential etiologies for these deficits, we compared their brain's structural and white matter organization to 22 controls using structural and diffusion magnetic resonance imaging. Diffusion images were processed to calculate fractional anisotropy (FA) and perform tract reconstructions. Cortical parcellation-based network analysis and gyral topology-based FA analyses were performed. Major interhemispheric, projection and intrahemispheric tracts were manually segmented. Subjects had decreased corpus callosum volume and decreased network efficiency. While only pediatric subjects had diffuse decreases in FA predominantly affecting mid- and long-range tracts, only adult subjects had white matter volume loss associated with decreased cortical surface area. All subjects showed aberrant corticospinal tract trajectory and bilateral absence of the dorsal language network long segment. Furthermore, pediatric subjects had more tracts with decreased FA compared with controls than did adult subjects. These findings define a TUBB3 E410K neuroimaging endophenotype and lead to the hypothesis that the age-related changes are due to microscopic intrahemispheric misguided axons that are pruned during maturation.

scholarly journals Alterations in Diffusion Measures of White Matter Integrity Associated with Healthy Aging

2019 ◽  
Author(s):  
Ciara J Molloy ◽  
Sinead Nugent ◽  
Arun L W Bokde
Keyword(s):  
White Matter ◽  
Healthy Aging ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
B Value ◽  
White Matter Hyperintensity ◽  
Normal Appearing White Matter ◽  
Age Related ◽  
Aging Adults ◽  
The Impact

Abstract This study aimed to characterize age-related white matter changes by evaluating patterns of overlap between the linear association of age with fractional anisotropy (FA) with mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Specifically, we assessed patterns of overlap between diffusion measures of normal appearing white matter by covarying for white matter hyperintensity (WMH) load, as WMHs are thought to increase with age and impact diffusion measures. Seventy-nine healthy adults aged between 18 and 75 years took part in the study. Diffusion tensor imaging (DTI) data were based on 61 directions acquired with a b-value of 2,000. We found five main patterns of overlap: FA alone (15.95%); FA and RD (31.90%); FA and AD (12.99%); FA, RD, and AD (27.93%); and FA, RD, and MD (8.79%). We showed that cognitively healthy aging adults had low WMH load, which subsequently had minimal effect on diffusion measures. We discuss how patterns of overlap may reflect underlying biological changes observed with aging such as loss of myelination, axonal damage, as well as mild microstructural and chronic white matter impairments. This study contributes to understanding the underlying causes of degeneration in specific regions of the brain and highlights the importance of considering the impact of WMHs in aging studies of white matter.

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