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Neural Correlates and Modifiers of Cognitive Aging

In collaboration with Dr. Raz, we recently demonstrated the first in vivo evidence of continued myelination of white matter axons well into the 4th decade of adults by modeling the short spin-spin (T2) relaxation component from multi-echo T2 relaxation imaging. Results showed an inverted ā€œUā€ trajectory in the myelin content of key white matter areas across the adult lifespan reflecting the continued myelination, but more importantly, demonstrates myelination during brain development. No otherin vivo neuroimaging techniques including diffusion tensor imaging (DTI) or T1/T2 ratio imaging have been able to demonstrate these specific changes in myelin content with age. Also, we have demonstrated that the myelin imaging method is highly reliable and thus well-suited for longitudinal studies.

With Dr. Raz as the PI, we are investigating the relationship between age-related changes in the brain and cognition and to examine the mechanisms that may underlie these associations, specifically, changes in brain energy metabolism. We aim to establish whether the in healthy older adults, brain changes in volume, myelin content, iron deposition and energy metabolism are related to change in cognitive performance and whether changes in one domain (e.g., energy metabolism) drive changes in other aspects of brain health.

Publications:
  1. Arshad M*, Stanley JA, Raz N. Adult Age Differences in Subcortical Myelin Content Are Consistent with Protracted Myelination and Unrelated to Diffusion Tensor Imaging Indices. NeuroImage. 2016; 143: 26-39.
  2. Arshad M*, Stanley JA, Raz N. Test ā€“ Retest Reliability and Concurrent Validity of in vivo Myelin Content Indices: Myelin Water Fraction and Calibrated T1W/T2W Image Ratio. Human Brain Mapping. 2017; 38: 1780-17-90.
For further publications, see: scholar.google.com/citations?user=Q6WT00IAAAAJ&hl=en