Cortical complexity as a measure of age-related brain atrophy.
The structure of the human brain changes in a variety of ways as we age. While a sizeable literature has examined age-related differences in cortical thickness, and to a lesser degree, gyrification, here we examined differences in cortical complexity, as indexed by fractal dimensionality in a sample of over 400 individuals across the adult lifespan. While prior studies have shown differences in fractal dimensionality between patient populations and age-matched, healthy controls, it is unclear how well this measure would relate to age-related cortical atrophy. Initially computing a single measure for the entire cortical ribbon, i.e., unparcellated gray matter, we found fractal dimensionality to be more sensitive to age-related differences than either cortical thickness or gyrification index. We additionally observed regional differences in age-related atrophy between the three measures, suggesting that they may index distinct differences in cortical structure. We also provide a freely available MATLAB toolbox for calculating fractal dimensionality.
Department of Psychology, Boston College, USA. Electronic address: madanc@bc.edu.
Christopher R
CR
Madan
Department of Psychology, Boston College, USA.
Elizabeth A
EA
Kensinger
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D001284:Atrophy; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D066128:Gray Matter / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D066127:White Matter / Q000473:pathology; D055815:Young Adult
Age; Atrophy; Cortical structure; Cortical thickness; Fractal dimensionality; Gyrification