Charles H. Hillman - US grants

The long-term goals of this proposal are to identify factors that may be related to the increased health and effective functioning of older individuals. Physical activity has been previously shown to affect efficiency of cognitive and motor performance in older adults. These differences in performance are directly related to decreased life satisfaction, restrictions in mobility and social activity, increases in depression, and the incidence of injury due to falls. The proposed project will isolate components of the stimulus-response relationship to determine the exact loci that may be affected by aging and, further, which loci are ameliorated by aerobic fitness. To achieve this goal, a three-stimulus paradigm (S1-S2-S3) will be used to examine event-related potentials (i.e., CNV, SPN, and P3) and reaction time (RT) in four groups of individuals: older and younger physically active and sedentary adults. Previous research has indicated that these evoked potential measures differentially index the stimulus-response relationship, with the SPN reflecting stimulus anticipation, CNV indexing both stimulus orienting and motor preparation, and P3 amplitude and latency reflecting context updating and cognitive processing speed, respectively. The S1 will be a visual warning stimulus that provides information as to whether the upcoming task at S2 will be easy or difficult. S2 will be a discrimination task in which the participant will be instructed to make a decision but to hold their response until the presentation of S3, at which point they will make a choice RT response. It is hypothesized that a main effect for age will occur for all ERP amplitudes (i.e., SPN, CNV, and P3), and latencies (i.e., P3 and RT). It is further hypothesized that physical activity levels will interact with age resulting in increased amplitude and shorter latencies for all measures. It is proposed that the results of this fellowship will aid in advancing our knowledge concerning the health of older adults.

[unreadable] DESCRIPTION (provided by applicant): This aim of this research is to gain a better understanding of factors that relate to the increased health and effective functioning of older adults. Specifically, efficiency of psychomotor performance declines with advancing age leading to profound effects on older adults' quality of life. For this reason, researchers have focused on the influence that individual lifestyle habits have on the aging process. One lifestyle choice that has been found to positively contribute to the efficiency of older adults' psychomotor performance is cardiovascular exercise. This relationship appears to be especially significant when older adults are challenged with more complex or effortful tasks. Two lines of research are relevant here. First, age-related discrepancies have been documented using tasks that require executive control processes that are subserved by the frontal lobes. These differences are not consistently observed using tasks that are not subserved by the frontal lobes, leading investigators to believe that aging has a specific, rather than generalized, impact on cognitive functioning. Secondly, prolonged participation in cardiovascular exercise has been found to maintain the cognitive functioning critical for healthy aging. Therefore, the purpose of this research is to examine the role of a 6-month cardiovascular exercise intervention trial on electrocortical (ERPs) and behavioral measures (RT) of executive control processes. In addition, a non-cardiovascular exercise control group that participates in a 6-month stretching and toning program will be used for comparison. Participants will be measured before and after exercise training during engagement in several tasks designed to elicit different executive functions (e.g., interference control, task switching, inhibition). Each task also contains a non-executive condition that will be used for comparison to examine the specificity of exercise participation of cognitive functioning. A secondary aim of this project is to determine the effects of an acute bout of exercise on cognitive functioning. Both groups will participate in several bouts of exercise followed by immediate measurement on the tasks outlined above to determine whether acute exercise has beneficial effects on executive control processes. The significance of this research may include the increased understanding of factors related to the amelioration of age-related decrements in central nervous system functioning and recommendations for the maintenance of cognitive health during the later stages of life. [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): The aim of this proposal is to improve our understanding of factors related to cognitive health of school-aged children by examining the effects of a 9-month exercise intervention on basic and applied aspects of cognition in preadolescent children. From a basic measurement perspective, event-related brain potentials (i.e., neuroelectric activity in response to, or in preparation for, a stimulus or response) and behavioral (i.e., reaction time, response accuracy) indices of cognition will be studied during several tasks aimed at assessing various aspects of executive control (i.e., a subset of processes concerned with the selection, scheduling, and coordination of computational processes responsible for perception, memory, and action). Preliminary research has observed faster and more efficient performance in high-fit, relative to low-fit, children and adults using neuroelectric measures that reflect attentional allocation to environmental stimuli (i.e., P3) and response monitoring processes (i.e., ERN, Pe), along with behavioral measures that reflect response speed and accuracy. These preliminary findings indicate greater top-down attentional control may be associated with increases in physical activity. From an applied measurement perspective, preliminary research has found that children with greater aerobic fitness perform better on standardized achievement tests of reading and mathematics, compared to children with lower aerobic fitness, suggesting that exercise may be related to academic performance in an applied school setting. To date, no causal evidence exists regarding the effects of physical activity on neuroelectric, behavioral, or applied school performance indices of cognition in children. Accordingly, this proposal investigates an aerobic physical activity training intervention on these measures of cognition using three tasks (single stimulus, Go/NoGo, flanker) that require variable amounts of executive control, and on the Illinois Standardized Achievement Test using a randomized control design in which particiants are assigned to an afterschool physical activity program or a wait-list control group. Given recent trends identifying decreased levels of physical activity and health status in preadolescents, the understanding of the potential benefits of physical activity on cognition is of great interest. It is imperative that factors positively influencing cognitive function of children be examined to maximize health and effective functioning of individuals as they progress through the lifespan. PUBLIC HEALTH RELEVANCE: recent trends have identified decreasing levels of physical activity, fitness, and health in preadolescent children. Examining factors, such as physical activity behavior and aerobic fitness that positively influence cognitive health of school-age children are important for improving school performance, maximizing health, and improving the overall functioning of individuals as they progress through the human lifespan. A sample of preadolescent children from the Urbana, Illinois elementary school system will be randomly assigned to a 9- month afterschool program that focuses on either aerobic exercise or wait-list control group to determine the effects of physical activity on basic and applied aspects of cognition. Changes in neuroelectric and behavioral indices of cognitive function and performance on standardized academic achievement tests of mathematics and reading will be examined as a function of participation in the intervention. Preliminary research supports that physical activity is positively associated with basic and applied aspects of cognition, with a stronger relationship for tasks requiring extensive amounts of executive control. However, previous research has mainly focused on older adults, and little research has examined the relationship between physical activity and executive control in children. These findings will provide lifestyle considerations for children to improve their cognitive health across the lifespan. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): The long term objective of this project is to develop an understanding of lifestyle factors that influence the cognitive and brain health of children while also reducing the sedentary nature of today's youth. Previous research conducted by our research team and others has found that physical activity interventions can enhance both a variety of aspects of cognition and brain structure and function of children, older adults, and individuals with neurodegenerative disorders such as Parkinson's disease and multiple sclerosis. More specifically, in our research with children we have found that higher fit children possess larger hippocampi which in turn are related to better relational memory than their lower fit counterparts. We have also observed that higher fit children exhibit more efficient executive control as indicated by performance measures and event-related brain potentials. While intriguing, these cross-sectional data do not enable us to establish causality between physical activity and cognition. In the current proposal we substantially extend this previous research by examining the influence of a 9 month randomized controlled afterschool physical activity program on cognition and brain health. Cognition will be assessed with a battery of tasks and standardized achievement tests both before and after the 9 month intervention in the activity group and a wait list control (who will receive the intervention the following year). Children will also participate in magnetic resonance imaging (MRI) sessions both before and after the intervention (and at comparable times for the wait list control). In these sessions we will measure both structural aspects of the brain including regional volumes of gray matter and the integrity of the white matter tracts (through diffusion tensor imaging) and functional aspects of brain function using fMRI activity recorded as the children perform a series of executive control and memory tasks. We anticipate, based on our cross-sectional studies with children and our previous longitudinal studies with older adults, that the children in the physical activity program will show both larger regional brain volumes, particularly in brain regions that subserve executive control and relational memory, and more efficient brain function, as indexed by task-related and resting state fMRI. Furthermore, we anticipate that these changes will be accompanied by improvements in memory and executive control processes. Given recent trends identifying decreased levels of physical activity and health status in preadolescents, the understanding of the potential benefits of physical activity on cognition is of great interest. It s imperative that factors positively influencing cognitive function of children be examined to maximize health and effective functioning of individuals as they progress through the lifespan. PUBLIC HEALTH RELEVANCE: Recent national and international trends have identified decreasing levels of physical activity, fitness, and health in preadolescent children. Examining factors, such as physical activity behavior and aerobic fitness that positively influence brain health and cognition of school-age children are important for improving school performance, maximizing overall health, and improving the function of individuals as they progress through the human lifespan. In our proposed research we will examine, for the first time in a randomized controlled trial, the influence of a 9 month after school physical activity program on the cognitiv and brain health of pre- adolescent children.

Project Summary/Abstract Despite widespread public health campaigns, children have become increasingly inactive, leading to public health concerns for children of industrialized nations. In addition to physical health issues (e.g., the recent obesity pandemic), physical inactivity has been related to decreased cognitive and academic performance, with a wealth of literature indicating that physical activity is positively related to brain and cognition. The significance of this proposal lies in uncovering a biomarker that links the beneficial effects of a single bout of aerobic exercise to childhood brain, cognition, and academic achievement. To date, no such explanatory mechanism has been demonstrated in the literature. Given the importance of physical activity to brain health and cognition, we propose to investigate phasic shifts in sympathetic nervous system (SNS) activity using the biomarker salivary alpha-amylase (sAA), as a potential mechanism mediating the beneficial effect of a single bout of exercise on brain, cognition, and achievement in children using a randomized crossover design. sAA is phasically increased during physical and psychosocial stress as part of the first wave of the `fight or flight' response. Stress-induced modulation of sAA has been related to alterations in prefrontally-mediated executive control functions (i.e., inhibition, working memory, cognitive flexibility) and academic achievement in children. This proposal aims to study phasic shifts in sAA following a bout of aerobic exercise, and relate such changes to measures of brain function (i.e., the P3 component of an event-related brain potential), executive control, and performance on standardized achievement tests of reading and arithmetic. In this regard, the proposed research will be the among the first to investigate the molecular underpinnings of the acute exercise-induced changes in cognition and brain in children through a combination of molecular, neuroimaging, behavioral, and academic achievement measures. Through the collection of salivary, neuroimaging, and behavioral outcomes in the proposed randomized crossover experiments, we can begin to establish the multidimensional nature of the transient effects of a single bout of exercise on the underlying molecular and neural changes that promote cognitive health and academic achievement during childhood. Findings consistent with our general hypothesis, that the SNS mediates exercise effects on brain, cognition, and achievement, has considerable implications for understanding factors that lead to maximizing physical health, neurocognitive function, and the educational experience. Such empirical support stands to benefit educational practices and current methods of learning, and provides the necessary `hard evidence' to promote the adoption of exercise during the school day to improve the cognitive health and scholastic performance of a broad range of children. Accordingly, the proposed research is not only aimed at determining a mechanism underlying the effects of a single bout of exercise on cognitive and brain health, but also at curbing the public health issue of inactivity that is decreasing the health, wellness, and academic potential of our nation's children.