School of Public Health

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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.

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Now showing 1 - 5 of 5
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    Emotional processing and positive affect after acute exercise in healthy older adults
    (Wiley, 2023-06-12) Kommula, Yash; Purcell, Jeremy J.; Callow, Daniel D.; Won, Junyeon; Pena, Gabriel S.; Smith, J. Carson
    The well-elucidated improvement of mood immediately after exercise in older adults presumably involves adaptations in emotion-processing brain networks. However, little is known about effects of acute exercise on appetitive and aversive emotion-related network recruitment in older adults. The purpose of this study was to determine the effect of acute exercise, compared to a seated rest control condition, on pleasant and unpleasant emotion-related regional activation in healthy older adults. Functional MRI data were acquired from 32 active older adults during blocked presentations of pleasant, neutral and unpleasant images from the International Affective Pictures System. fMRI data were collected after participants completed 30 min of moderate to vigorous intensity cycling or seated rest, performed in a counterbalanced order across separate days in a within-subject design. The findings suggest three ways that emotional processing in the brain may be different immediately after exercise (relative to immediately after rest): First, reduced demands on emotional regulation during pleasant emotional processing as indicated by lower precuneus activation for pleasant stimuli; second, reduced processing of negative emotional stimuli in visual association areas as indicated by lower activation for unpleasant stimuli in the bilateral fusiform and ITG; third, an increased recruitment in activation associated with regulating/inhibiting unpleasant emotional processing in the bilateral medial superior frontal gyrus (dorsomedial prefrontal cortex), angular gyri, supramarginal gyri, left cerebellar crus I/II and a portion of right dorsolateral prefrontal cortex. Overall, these findings support that acute exercise in active older adults alters activation in key emotional processing and regulating brain regions.
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    The Impact of Acute Aerobic Exercise on Semantic Memory Activation in Healthy Older Adults
    (2018) Won, Junyeon; Smith, Jerome C; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Background: A growing body of exercise literature use functional magnetic resonance imaging (fMRI) technique to measure the effects of exercise on the brain. Findings suggest that regular participation of long-term exercise is associated with enhanced cognitive function. However, fundamental questions regarding the beneficial effects of acute exercise on semantic memory have been ignored. Purpose: This study investigated the effects of a single session of exercise on brain activation during recognition of Famous names and Non-Famous names compared to seated-rest in healthy older adults (age 65-85) using fMRI. We also aimed to measure whether there are differences in brain activation during retrieval of Famous names from three distinct time epochs (Remote, Enduring, and Recent) following acute exercise. Methods: Using a within-subjects counterbalanced design, 30 participants (ages 55-85) will undergo two experimental visits on separate days. During each visit, participants will engage in 30-minutes of rest or stationary cycling exercise immediately followed by the famous name discrimination task (FNT). Neuroimaging and behavioral data will be processed using AFNI (version 17.1.06) and SPSS (version 23), respectively. Results: HR and RPE were significantly higher during exercise. Acute exercise was associated with significantly greater semantic memory activation (Famous > Non-Famous) in five out of nine regions (p-value ranged 0.027 to 0.046). In an exploratory epoch analysis, five out of 14 brain regions activated ruing the semantic memory task showed significantly greater activation intensity following the exercise intervention (Enduringly Famous > Non-Famous). Conclusions: Enhanced semantic memory processing is observed following acute exercise, characterized by greater fMRI response to Famous than Non-Famous names. Enduringly Famous names exhibited significantly greater activation after exercise compared to Non-Famous names. These findings suggest that exercise may improve semantic memory retrieval in healthy older adults, and may lead to enhancement of cognitive function.
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    FUNCTIONAL CONNECTIVITY PATTERNS ASSOCIATED WITH AGING, PHYSICAL ACTIVITY, AND GENETIC RISK FOR ALZHEIMER’S DISEASE IN HEALTHY HUMAN BRAIN NETWORKS.
    (2017) Chirles, Theresa Jeanne; Smith, Carson J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Leisure time physical activity (PA) and exercise training help to improve and maintain cognitive function in healthy older adults and in adults with the APOE-ε4 allele, a genetic risk for Alzheimer’s Disease (AD). Earlier work finding increased functional connectivity in the Default Mode Network (DMN) after a 12-week walking intervention in 16 older adults with mild cognitive impairment is presented in Chapter 3. The primary dissertation study investigating differences in brain function depending on PA level and genetic risk for AD prior to changes in cognition is presented in Chapters 4-6. Useable resting state and anatomical MRI scans were collected from 69 healthy adults (22-51 years) as well as saliva for APOE genotyping (carriers defined as homozygotes or heterozygotes of the ɛ4 allele) and responses to the Paffenbarger Physical Activity Questionnaire (High PA >1500 kcal, Low PA <1500 kcal per week). The following network measures of functional connectivity were calculated: global efficiency; node strength of Default Mode Network (DMN) and Fronto-Parietal Network (FPN) hubs and hippocampal subsections; and long-range connectivity of the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC) in the DMN. Multiple linear regression analysis revealed statistically significant results for the long-range connectivity of the left PCC, a prominent hub of the DMN, and left mPFC. The differences in projected trajectories of the connectivity are potentially reflective of the compensatory time-course in our participants based on interactions of PA level and APOE status. The Low PA non-carriers had a positive slope indicating increased connectivity with age while carriers and non-carriers in the High PA category had horizontal aging trajectories. PA is associated with cognitive reserve (CR), a term describing the protection and adaptation of cognitive processes through neural efficiency and compensation mechanisms, and it is possible the Low PA non-carriers exhibited compensatory increases in connectivity of the left mPFC-PCC earlier than High PA study participants due to lower levels of CR. The promising findings that rs-fMRI can be used as an early detection of brain changes sensitive to PA levels and APOE-ɛ4 status are critical to the research and treatment of AD.
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    THE IMPACT OF ACUTE EXERCISE AND SLEEP QUALITY ON EXECUTIVE FUNCTION: THE POTENTIAL MEDIATING EFFECTS OF FUNCTIONAL CONNECTIVITY IN OLDER ADULTS
    (2017) Alfini, Alfonso J.; Smith, J. Carson; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Background: Although, improved longevity is a major public health accomplishment, the prevalence of chronic disease, including cognitive impairment, increases with age. Insufficient sleep and physical inactivity exacerbate chronic disease and may accelerate the onset of dementia. While a cure remains elusive, a growing body of evidence demonstrates that exercise training facilitates better sleep and enhanced cognition. Exercise-altered patterns of neural activity, including resting state functional connectivity (rsFC) and task-based functional activation, likely coincide with and may facilitate cognitive improvements in the aging brain. Purpose: This study sought to examine the joint impact of acute exercise and sleep quality on executive function in older adults. We also aimed to determine the degree to which exercise-induced changes in prefrontal rsFC influence the relationship between sleep and executive function performance/functional activation. Methods: Using a within subjects counter-balanced design, 21 participants (aged 55-85) underwent at least three days of objective sleep monitoring (actigraphy), followed by two experimental visits on separate days. During each visit, participants engaged in 30-minutes of rest or exercise followed immediately by resting state and task-based functional MRI. After the MRI scanning session, participants completed several executive function assessments. Neuroimaging and behavioral data were processed using AFNI (version 17.1.06) and SPSS (version 23), respectively. Results: Repeated measures ANOVA and multivariate linear regression revealed two significant voxel-wise interactions in the (L) precuneus. Our findings demonstrated that acute exercise increased prefrontal rsFC and functional activation in long sleepers (> 7.5 hours/night), while decreasing these parameters for individuals with less total sleep time. Moreover, these results correspond to behavioral data demonstrating that acute exercise and adequate sleep improved select aspects of executive function performance, while decreasing inhibitory control in short sleepers alone (< 7.5 hours). Conclusion: These findings suggest that the effects of acute exercise on prefrontal rsFC are similar, or even related, to the effects of acute exercise on conflict-dependent functional activation, and that this relationship may depend on sleep duration. Moreover, our results imply that although acute exercise elicited improved executive function for those with adequate sleep, it may weaken already vulnerable, and perhaps fatigued, executive function networks among short sleepers.
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    Latent and Abnormal Functional Connectivity Circuits in Autism Spectrum Disorder
    (Frontiers, 2017-03-21) Chen, Shuo; Xing, Yishi; Kang, Jian
    Autism spectrum disorder (ASD) is associated with disrupted brain networks. Neuroimaging techniques provide noninvasive methods of investigating abnormal connectivity patterns in ASD. In the present study, we compare functional connectivity networks in people with ASD with those in typical controls, using neuroimaging data from the Autism Brain Imaging Data Exchange (ABIDE) project. Specifically, we focus on the characteristics of intrinsic functional connectivity based on data collected by resting-state functional magnetic resonance imaging (rs-fMRI). Our aim was to identify disrupted brain connectivity patterns across all networks, instead of in individual edges, by using advanced statistical methods. Unlike many brain connectome studies, in which networks are prespecified before the edge connectivity in each network is compared between clinical groups, we detected the latent differentially expressed networks automatically. Our network-level analysis identified abnormal connectome networks that (i) included a high proportion of edges that were differentially expressed between people with ASD and typical controls; and (ii) showed highly-organized graph topology. These findings provide new insight into the study of the underlying neuropsychiatric mechanism of ASD.