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Search Results: 1 - 10 of 89001 matches for " Kirk I. Erickson "
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Age-Related Decline in Controlled Retrieval: The Role of the PFC and Sleep
Kristine A. Wilckens,Kirk I. Erickson,Mark E. Wheeler
Neural Plasticity , 2012, DOI: 10.1155/2012/624795
Abstract: Age-related cognitive impairments often include difficulty retrieving memories, particularly those that rely on executive control. In this paper we discuss the influence of the prefrontal cortex on memory retrieval, and the specific memory processes associated with the prefrontal cortex that decline in late adulthood. We conclude that preretrieval processes associated with preparation to make a memory judgment are impaired, leading to greater reliance on postretrieval processes. This is consistent with the view that impairments in executive control significantly contribute to deficits in controlled retrieval. Finally, we discuss age-related changes in sleep as a potential mechanism that contributes to deficiencies in executive control that are important for efficient retrieval. The sleep literature points to the importance of slow-wave sleep in restoration of prefrontal cortex function. Given that slow-wave sleep significantly declines with age, we hypothesize that age-related changes in slow-wave sleep could mediate age-related decline in executive control, manifesting a robust deficit in controlled memory retrieval processes. Interventions, like physical activity, that improve sleep could be effective methods to enhance controlled memory processes in late life. 1. Introduction Age-related cognitive impairments often include decline in executive control critical for strategic controlled memory retrieval [1–4]. Volumetric studies have suggested that atrophy of the prefrontal cortex (PFC) mediates age-related decline in executive control [5, 6]. Impairments in executive control include difficulties selecting relevant and inhibiting irrelevant information and actions, and difficulties monitoring and updating information [7, 8]. Further, white matter in older adults is particularly compromised in anterior brain regions. This has been shown with white matter lesions [9] as well as white matter integrity assessed using diffusion tensor imaging (DTI) [10–12]. Such white matter breakdown disrupts the connectivity between frontal and other cortical regions, ultimately affecting executive control. These PFC changes tend to manifest themselves in a range of cognitive tasks including memory retrieval [3, 13, 14]. Given that decline in memory can be particularly debilitating in older adults, determining factors that contribute to PFC decline is of utmost importance. The prevalence of sleep disruption in older adults [15–17] and its negative impact on cognition [18, 19] suggest that sleep may play an important role in the extent to which older adults exhibit decline
Physical Exercise and Brain Functions in Older Adults
Louis Bherer,Kirk I. Erickson,Teresa Liu-Ambrose
Journal of Aging Research , 2013, DOI: 10.1155/2013/197326
Abstract:
A Review of the Effects of Physical Activity and Exercise on Cognitive and Brain Functions in Older Adults
Louis Bherer,Kirk I. Erickson,Teresa Liu-Ambrose
Journal of Aging Research , 2013, DOI: 10.1155/2013/657508
Abstract: Studies supporting the notion that physical activity and exercise can help alleviate the negative impact of age on the body and the mind abound. This literature review provides an overview of important findings in this fast growing research domain. Results from cross-sectional, longitudinal, and intervention studies with healthy older adults, frail patients, and persons suffering from mild cognitive impairment and dementia are reviewed and discussed. Together these finding suggest that physical exercise is a promising nonpharmaceutical intervention to prevent age-related cognitive decline and neurodegenerative diseases. 1. Introduction Chronological aging, or senescence, is associated with an increased risk of chronic conditions and diseases such as cognitive impairment, cardiovascular disease, and metabolic syndrome. Due to prolonged life expectancy, age-related diseases have increased in alarming proportions in recent decades [1]. An increasing body of studies have suggested that lifestyle factors have a significant impact on how well people age. For example, Fratiglioni et al. [2] reported that three lifestyle factors can play a significant role in slowing the rate of cognitive decline and preventing dementia: a socially integrated network, cognitive leisure activity, and regular physical activity. In this review and others [3, 4], it is argued that out of these lifestyle factors, physical activity has the most support as protective against the deleterious effects of age on health and cognition. Broadly defined, physical activity refers to activity that is part of one’s daily life involving bodily movements and the use of skeletal muscles. Physical exercise is a subcategory of physical activity that is planned, structured, and purposive to improve specific physical skills or physical fitness. Evidence suggests that physical activity and exercise can to some extent lower the risk of adverse outcomes associated with advancing age. Physical activity maintained throughout life is associated with lower incidence and prevalence of chronic diseases such as cancer, diabetes and cardiovascular and coronary heart diseases [5, 6]. Recent studies suggest that physical exercise also protects against dementia [7]. Yet, despite this promise, the ways in which physical activity impacts the rate and prevalence of cognitive decline is still under investigation. Furthermore, several open issues call for further research, such as the dose-response relationship, the level of change or protection provided by physical activity, the biological and/or psychological
A protocol for a randomized clinical trial of interactive video dance: potential for effects on cognitive function
Jelena Jovancevic, Caterina Rosano, Subashan Perera, Kirk I Erickson, Stephanie Studenski
BMC Geriatrics , 2012, DOI: 10.1186/1471-2318-12-23
Abstract: This paper describes a randomized clinical trial in 168 postmenopausal sedentary overweight women that compares an interactive video dance game with brisk walking and delayed entry controls. The primary endpoint is adherence to activity at six months. Additional endpoints include aspects of physical and mental health. We focus this report primarily on the rationale and plans for assessment of multiple cognitive functions.This randomized clinical trial may provide new information about the cognitive effects of interactive videodance. It is also the first trial to examine physical and cognitive effects in older women. Interactive video games may offer novel strategies to promote physical activity and health across the life span.The study is IRB approved and the number is: PRO08080012ClinicalTrials.gov Identifier: NCT01443455
Physical activity and brain plasticity in late adulthood: a conceptual and comprehensive review
Kirk I. Erickson,Destiny L. Miller,Andrea M. Weinstein,Stephanie L. Akl
Ageing Research , 2012, DOI: 10.4081/ar.2012.e6
Abstract: A growing body of evidence from neuroscience, epidemiology, and kinesiology suggests that physical activity is effective as both a prevention and treatment for cognitive problems throughout the lifespan. Given the expected increase in the proportion of older adults in most countries over the next 40 years, physical activity could be a low-cost and relatively accessible method for maintaining cognitive function throughout later life. Despite the emerging recognition of physical activity as a powerful method to enhance brain health, there is continued confusion from both the public and scientific communities about what the extant research has discovered about the potential for physical activity to improve neurocognitive health and which questions remain unanswered. In this review, we outline four overarching themes that provide a conceptual structure for understanding the questions that have been asked and have been addressed, as well as those that have yet to be answered. These themes are descriptive, mechanistic, applied, and moderating questions. We conclude from our review that descriptive questions have been the first and most thoroughly studied, but we have much yet to learn about the underlying mechanisms, application, and moderating factors that explain how and to what extent physical activity improves brain health.
Potential Moderators of Physical Activity on Brain Health
Regina L. Leckie,Andrea M. Weinstein,Jennifer C. Hodzic,Kirk I. Erickson
Journal of Aging Research , 2012, DOI: 10.1155/2012/948981
Abstract:
Potential Moderators of Physical Activity on Brain Health
Regina L. Leckie,Andrea M. Weinstein,Jennifer C. Hodzic,Kirk I. Erickson
Journal of Aging Research , 2012, DOI: 10.1155/2012/948981
Abstract: Age-related cognitive decline is linked to numerous molecular, structural, and functional changes in the brain. However, physical activity is a promising method of reducing unfavorable age-related changes. Physical activity exerts its effects on the brain through many molecular pathways, some of which are regulated by genetic variants in humans. In this paper, we highlight genes including apolipoprotein E (APOE), brain derived neurotrophic factor (BDNF), and catechol-O-methyltransferase (COMT) along with dietary omega-3 fatty acid, docosahexaenoic acid (DHA), as potential moderators of the effect of physical activity on brain health. There are a growing number of studies indicating that physical activity might mitigate the genetic risks for disease and brain dysfunction and that the combination of greater amounts of DHA intake with physical activity might promote better brain function than either treatment alone. Understanding whether genes or other lifestyles moderate the effects of physical activity on neurocognitive health is necessary for delineating the pathways by which brain health can be enhanced and for grasping the individual variation in the effectiveness of physical activity interventions on the brain and cognition. There is a need for future research to continue to assess the factors that moderate the effects of physical activity on neurocognitive function. 1. Introduction One in every eight US seniors over the age of 65 has been diagnosed with Alzheimer’s disease (AD), amounting to more than 5.4 million people. With the aging baby boomers, this number is predicted to double by 2050 [1]. Unfortunately, pharmaceuticals have had limited success in preventing or treating age-related cognitive dysfunction, such as AD or even normal cognitive aging. Fortunately, physical activity appears to be a promising nonpharmaceutical method to attenuate cognitive dysfunction in late life [2, 3]. Yet, there remain many unanswered questions about the effectiveness of physical activity to improve brain health, prevent dementia, and reduce age-related cognitive decline. “Physical activity” is an umbrella term defined by the Center for Disease Control (CDC) as any activity that increases heart rate and energy expenditure from one’s basal level [4]. Examples of physical activities are walking, gardening, or even household chores such as cleaning. In turn, “exercise” is defined as a subcategory of physical activity, being any structured or repetitive activity that aims to improve fitness, endurance, or health such as strength training, purposefully running, or
Aging Brain from a Network Science Perspective: Something to Be Positive About?
Michelle W. Voss, Chelsea N. Wong, Pauline L. Baniqued, Jonathan H. Burdette, Kirk I. Erickson, Ruchika Shaurya Prakash, Edward McAuley, Paul J. Laurienti, Arthur F. Kramer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078345
Abstract: To better understand age differences in brain function and behavior, the current study applied network science to model functional interactions between brain regions. We observed a shift in network topology whereby for older adults subcortical and cerebellar structures overlapping with the Salience network had more connectivity to the rest of the brain, coupled with fragmentation of large-scale cortical networks such as the Default and Fronto-Parietal networks. Additionally, greater integration of the dorsal medial thalamus and red nucleus in the Salience network was associated with greater satisfaction with life for older adults, which is consistent with theoretical predictions of age-related increases in emotion regulation that are thought to help maintain well-being and life satisfaction in late adulthood. In regard to cognitive abilities, greater ventral medial prefrontal cortex coherence with its topological neighbors in the Default Network was associated with faster processing speed. Results suggest that large-scale organizing properties of the brain differ with normal aging, and this perspective may offer novel insight into understanding age-related differences in cognitive function and well-being.
Caudate Nucleus Volume Mediates the Link between Cardiorespiratory Fitness and Cognitive Flexibility in Older Adults
Timothy D. Verstynen,Brighid Lynch,Destiny L. Miller,Michelle W. Voss,Ruchika Shaurya Prakash,Laura Chaddock,Chandramallika Basak,Amanda Szabo,Erin A. Olson,Thomas R. Wojcicki,Jason Fanning,Neha P. Gothe,Edward McAuley,Arthur F. Kramer,Kirk I. Erickson
Journal of Aging Research , 2012, DOI: 10.1155/2012/939285
Abstract: The basal ganglia play a central role in regulating the response selection abilities that are critical for mental flexibility. In neocortical areas, higher cardiorespiratory fitness levels are associated with increased gray matter volume, and these volumetric differences mediate enhanced cognitive performance in a variety of tasks. Here we examine whether cardiorespiratory fitness correlates with the volume of the subcortical nuclei that make up the basal ganglia and whether this relationship predicts cognitive flexibility in older adults. Structural MRI was used to determine the volume of the basal ganglia nuclei in a group of older, neurologically healthy individuals (mean age 66 years, ?? = 1 7 9 ). Measures of cardiorespiratory fitness ( V O 2 m a x ), cognitive flexibility (task switching), and attentional control (flanker task) were also collected. Higher fitness levels were correlated with higher accuracy rates in the Task Switching paradigm. In addition, the volume of the caudate nucleus, putamen, and globus pallidus positively correlated with Task Switching accuracy. Nested regression modeling revealed that caudate nucleus volume was a significant mediator of the relationship between cardiorespiratory fitness, and task switching performance. These findings indicate that higher cardiorespiratory fitness predicts better cognitive flexibility in older adults through greater grey matter volume in the dorsal striatum. 1. Introduction Age-related cognitive decline is an unfortunate, but nearly ubiquitous, characteristic of late life that is preceded by atrophy of several brain regions including the prefrontal cortex, medial temporal lobe, and basal ganglia [1, 2]. Because of the expected increase in the proportion of adults over the age of 65 in the next forty years, it has become a major public health initiative to identify methods to prevent or reverse regional brain atrophy with the hope that this might concurrently improve cognitive performance [3]. Randomized trials of aerobic exercise have proven promising from this regard, with participation in exercise programs leading to greater prefrontal [4] and hippocampal volumes [5]. Nonrandomized longitudinal studies of physical activity [6, 7] and cross-sectional studies of cardiorespiratory fitness [8–10] have shown similar results, with more physical activity and higher fitness levels associated with greater volumes. Unfortunately, few studies have examined whether cardiorespiratory fitness levels in older adult humans are associated with brain areas other than the prefrontal cortex and hippocampus
Predicting Individuals' Learning Success from Patterns of Pre-Learning MRI Activity
Loan T. K. Vo,Dirk B. Walther,Arthur F. Kramer,Kirk I. Erickson,Walter R. Boot,Michelle W. Voss,Ruchika S. Prakash,Hyunkyu Lee,Monica Fabiani,Gabriele Gratton,Daniel J. Simons,Bradley P. Sutton,Michelle Y. Wang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0016093
Abstract: Performance in most complex cognitive and psychomotor tasks improves with training, yet the extent of improvement varies among individuals. Is it possible to forecast the benefit that a person might reap from training? Several behavioral measures have been used to predict individual differences in task improvement, but their predictive power is limited. Here we show that individual differences in patterns of time-averaged T2*-weighted MRI images in the dorsal striatum recorded at the initial stage of training predict subsequent learning success in a complex video game with high accuracy. These predictions explained more than half of the variance in learning success among individuals, suggesting that individual differences in neuroanatomy or persistent physiology predict whether and to what extent people will benefit from training in a complex task. Surprisingly, predictions from white matter were highly accurate, while voxels in the gray matter of the dorsal striatum did not contain any information about future training success. Prediction accuracy was higher in the anterior than the posterior half of the dorsal striatum. The link between trainability and the time-averaged T2*-weighted signal in the dorsal striatum reaffirms the role of this part of the basal ganglia in learning and executive functions, such as task-switching and task coordination processes. The ability to predict who will benefit from training by using neuroimaging data collected in the early training phase may have far-reaching implications for the assessment of candidates for specific training programs as well as the study of populations that show deficiencies in learning new skills.
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