Akshay Kohli (United States of America)
University of Wisconsin School of Medicine and Public Health
Geriatrics
Akshay is a 5th year PhD student in the lab of Dr. Barbara Bendlin at the Wisconsin ADRC. His research has been focused around applying MRI and PET imaging to understand the relationships between brain myelination, neurodegeneration, and biomarkers of Alzheimer’s disease. Specifically, his current research aims to understand how myelin specific to the cerebral cortex may be involved in the pathogenesis and progression of AD, and whether we can use quantitative MRI markers of cortical myelin to predict an individual’s likelihood of developing the disease or the chance that they decline more quickly. Following graduate school, he plans to continue working in the field of scientific research employing neuroimaging and computational methods to understand more mysteries about the brain.

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 Conference Calendar

EFFECTS OF AGE ON REGIONAL R1 MAY INDICATE DIFFERENTIAL CORTICAL MYELINATION IN DEMENTIA AND MCI COMPARED TO COGNITIVELY UNIMPAIRED INDIVIDUALS

Session Name
1770 - AD, FTD, LBD DIAGNOSIS. EEG & CLINICAL TRIALS & ADVANCES IN DRUG DEVELOPMENT (ID 234)
Session Type
SYMPOSIUM
Date
Sat, 19.03.2022
Session Time
05:15 PM - 07:45 PM
Room
ONSITE: 131-132
Lecture Time
05:30 PM - 05:45 PM
Presenter

Abstract

Aims

Alzheimer’s disease (AD) dementia risk increases with age; prior studies suggest that age-associated myelin degeneration may underlie the regional patterns of AD pathology that develop in AD. Quantitative R1 is highly sensitive to myelin content, as well as other tissue microstructures. Here we tested whether age-associated regional R1 differed among individuals with and without clinical diagnosis of mild cognitive impairment (MCI) and dementia.

Methods

Participants(N=341) underwent MPnRAGE MRI and cognitive assessment for diagnosis of unimpaired(N=291), MCI(N=27) or dementia(N=23). MPnRAGE-derived T1-weighted images and R1 maps were processed using FreeSurfer to estimate the pial and white matter surfaces (Figure 1). Mean R1 was extracted for each region of interest (ROI) in the Desikan-Killiany atlas. Multiple linear regression models were employed to test age-by-diagnosis interactions on R1 for each ROI, controlling for sex and APOE status.

Results

Participants with dementia showed significantly lower R1 with older age in the bilateral cuneus, precuneus, and superior parietal lobules as compared to MCI and unimpaired individuals. In entorhinal cortices, age-related increases in R1 were observed among individuals with dementia compared to MCI and unimpaired individuals. Differences in age-related R1 were also observed in the banks of the superior temporal sulci, whereby participants with MCI showed higher myelin content with older age (Figure 2) as compared to dementia and unimpaired individuals.

Conclusions

Brain regions typically affected by AD-related pathology showed significantly different age-related associations with cortical R1 between diagnostic groups, which could indicate differential myelination patterns. Future analyses will examine longitudinal trajectories of R1 in association with regional AD pathology.

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