BBS Faculty Research
Permanent URI for this communityhttps://hdl.handle.net/10735.1/2317
Browse
Browsing BBS Faculty Research by Author "0000 0000 0265 9301 (Park, DC)"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Item Decreased Segregation of Brain Systems across the Healthy Adult Lifespan(National Academy of Science) Chan, Micaela Y.; Park, Denise C.; Savalia, Neil K.; Petersen, Steven E.; Wig, Gagan S.; 0000 0000 0265 9301 (Park, DC); 92048764 (Park, DC); 74141364 (Park, DC)Healthy aging has been associated with decreased specialization in brain function. This characterization has focused largely on describing age-accompanied differences in specialization at the level of neurons and brain areas. We expand this work to describe systems-level differences in specialization in a healthy adult lifespan sample (n = 210; 20-89 y). A graph-theoretic framework is used to guide analysis of functional MRI resting-state data and describe systems-level differences in connectivity of individual brain networks. Young adults' brain systems exhibit a balance of within-and between-system correlations that is characteristic of segregated and specialized organization. Increasing age is accompanied by decreasing segregation of brain systems. Compared with systems involved in the processing of sensory input and motor output, systems mediating "associative" operations exhibit a distinct pattern of reductions in segregation across the adult lifespan. Of particular importance, the magnitude of association system segregation is predictive of long-term memory function, independent of an individual's age.Item Investigating Unique Environmental Contributions to the Neural Representation of Written Words: A Monozygotic Twin StudyPark, J.; Park, Denise C.; Polk, T. A.; 0000 0000 0265 9301 (Park, DC); 92048764 (Park, DC)The visual word form area (VWFA) is a region of left inferior occipitotemporal cortex that is critically involved in visual word recognition. Previous studies have investigated whether and how experience shapes the functional characteristics of VWFA by comparing neural response magnitude in response to words and nonwords. Conflicting results have been obtained, however, perhaps because response magnitude can be influenced by other factors such as attention. In this study, we measured neural activity in monozygotic twins, using functional magnetic resonance imaging. This allowed us to quantify differences in unique environmental contributions to neural activation evoked by words, pseudowords, consonant strings, and false fonts in the VWFA and striate cortex. The results demonstrate significantly greater effects of unique environment in the word and pseudoword conditions compared to the consonant string and false font conditions both in VWFA and in left striate cortex. These findings provide direct evidence for environmental contributions to the neural architecture for reading, and suggest that learning phonology and/or orthographic patterns plays the biggest role in shaping that architecture. © 2012 Park et al.