Browsing by Author "Manchella, Mohit"

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    Neurological Correlates of Social Bonding and Bridging
    (Oxford University Press, 2022-12-20) Manchella, Mohit; Logan, Paige; Perry, Brea; Peng, Siyun; Hamilton, Lucas; Risacher, Shannon; Saykin, Andrew; Apostolova, Liana; Neurology, School of Medicine
    Social connectedness has been linked to decreased rates of cognitive decline in later life. However, recent work suggests that particular social network characteristics (i.e., bonding and bridging) may buffer against age-related degeneration. The present study analyzes social network and structural MRI data of 176 older adults from the Social Networks and Alzheimer’s Disease (SNAD) study. Results indicate that increased social bridging is associated with greater grey matter (GM) volume in several limbic structures. Increased social bonding is associated with greater GM volumes in several cerebral cortex structures as well as greater volumes in some components of the limbic system. Most notably, the effects of bridging are primarily lateralized in the left hemisphere while the effects of bonding are observed mostly in the right hemisphere. These results suggest that the neurocognitive benefits of social connectedness depend on the preponderance of bridging and/or bonding ties in older adults’ social networks.
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    Social Networks and Cognitive Function: An Evaluation of Social Bridging and Bonding Mechanisms
    (Oxford University Press, 2022) Perry, Brea L.; McConnell, William R.; Peng, Siyun; Roth, Adam R.; Coleman, Max; Manchella, Mohit; Roessler, Meghann; Francis, Heather; Sheean, Hope; Apostolova, Liana A.; Radiology and Imaging Sciences, School of Medicine
    Background and objectives: Social connectedness has been linked prospectively to cognitive aging, but there is little agreement about the social mechanisms driving this relationship. This study evaluated 9 measures of social connectedness, focusing on 2 forms of social enrichment-access to an expansive and diverse set of loosely connected individuals (i.e., social bridging) and integration in a supportive network of close ties (i.e., social bonding). Research design and methods: This study used egocentric network and cognitive data from 311 older adults in the Social Networks in Alzheimer Disease study. Linear regressions were used to estimate the association between social connectedness and global cognitive function, episodic memory, and executive function. Results: Measures indicative of social bridging (larger network size, lower density, presence of weak ties, and proportion of non-kin) were consistently associated with better cognitive outcomes, while measures of social bonding (close ties, multiplex support, higher frequency of contact, better relationship quality, and being married) largely produced null effects. Discussion and implications: These findings suggest that the protective benefits of social connectedness for cognitive function and memory may operate primarily through a cognitive reserve mechanism that is driven by irregular contact with a larger and more diverse group of peripheral others.
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    Unraveling The Ambiguity Between Cognition And Depression: A Longitudinal Analysis Of Older Adults
    (Oxford University Press, 2022) Roessler, Meghann; Manchella, Mohit; Singh, Anmoldeep; Coleman, Max; Francis, Heather; Saykin, Andrew; Risacher, Shannon; Apostolova, Liana; Radiology and Imaging Sciences, School of Medicine
    Research on directionality of the relationship between cognitive functioning and depression is ambiguous, especially when considering implications for patients with mild cognitive impairment or Alzheimer disease (AD). Previous research suggests that depression in late life could be a pre-clinical manifestation of AD before other cognitive symptoms are detectable. Some research supports the hypothesis that level of depression can independently predict level of cognition. Other research suggests that depression is a risk factor for developing dementia or AD late in life. Further research on the impact of subjective cognitive decline versus objective cognitive performance in association with depressive symptoms is a critical area to explore. Using data from the Social Networks in Alzheimer Disease (SNAD) study and the Indiana Alzheimer Disease Research Center (IADRC), we conducted a preliminary longitudinal analysis of 196 focal subjects (Mage = 71.6 years, Pfemale = 63%). Interviews conducted one year apart were leveraged to elucidate the bidirectional relationship between depressive symptomology and cognition. Using a lagged dependent variable approach controlling for age, sex, race, and education, the results indicate that only executive function predicts depression at timepoint 2 (-0.31 SD, p< 0.001). However, depression predicts focal Cognitive Change Index (CCI) (0.06 SD, p< 0.05), processing speed (-0.04 SD, p< 0.05), and episodic memory (-0.04 SD, p< 0.05). Other cognitive domains examined, including attention, language, visual/spatial skills, MoCA score, and informant-rated CCI, were not significant as predictors or as outcomes. These results suggest that depression may be a more robust predictor of cognition than cognition is of depression.