Brain Networks In Aging Reorganization And Modulation By Interventions

Old adults undertake multiple reduced cognitive abilities in aging, which are accompanied with specific brain reorganization in forms of regional brain activity and brain tissues, inter-region connectivity, and topology of whole brain networks in both function and structure. The plasticity changes of brain activities in old adults are explained by the mechanisms of compensation and dedifferentiation. For example, older adults have been observed to have greater, usually bilateral, prefrontal activities during memory tasks compared to the typical unilateral prefrontal activities in younger adults, which was explained as a compensation for the reduced brain activities in visual processing cortices. Dedifferentiation is another mechanism to explain that old adults are with much less selective and less distinct activity in task-relevant brain regions compared with younger adults. A larger number of studies have examined the plasticity changes of brain from the perspective of regional brain activities. However, studies on only regional brain activities cannot fully elucidate the neural mechanisms of reduced cognitive abilities in aging, as multiple regions are integrated together to achieve advanced cognitive function in human brain. In recent years, brain connectivity/network, which targets how brain regions are integrated, have drawn increasing attention in neuroscience with the development of neuroimaging techniques and graph theoretical analysis. Connectivity quantifies functional association or neural fibers between two regions that may be spatially far separated, and graph theoretical analysis of brain network examines the complex interactions among multiple regions from the perspective of topology. Studies showed that compared to younger adults, older adults had altered strength of task-relevant functional connectivity between specific brain regions in cognitive tasks, and the alternation of connectivity are correlated to behavior performance. For example, older adults had weaker functional connectivity between the premotor cortex and a region in the left dorsolateral prefrontal cortex in a working memory task. Interventions like cognitive training and neuro-modulation (e.g., transcranial magnetic stimulation) have been shown to be promising in regaining or retaining the decreasing cognitive abilities in aging. However, only few neuroimaging studies have examined the influence of interventions to old adult’s brain activity, connectivity, and cognitive performance. This Research Topic calls for contributions on brain network of subjects in normal aging or with age-related diseases like mild cognitive impairment and Alzheimer’s disease. The studies are expected to be based on neuroimaging techniques including but not limited to functional magnetic resonance imaging, Electroencephalography, and diffusion tensor imaging, and contributions on the influence of interventions to brain networks in aging are highly encouraged. All these studies would enrich our understanding of neural mechanisms underlying aging, and offer new insights for developing possible interventions to retain cognitive abilities in aging subjects.

Old adults undertake multiple reduced cognitive abilities in aging, which are accompanied with specific brain reorganization in forms of regional brain activity and brain tissues, inter-region connectivity, and topology of whole brain networks in both function and structure. The plasticity changes of brain activities in old adults are explained by the mechanisms of compensation and dedifferentiation. For example, older adults have been observed to have greater, usually bilateral, prefrontal activities during memory tasks compared to the typical unilateral prefrontal activities in younger adults, which was explained as a compensation for the reduced brain activities in visual processing cortices. Dedifferentiation is another mechanism to explain that old adults are with much less selective and less distinct activity in task-relevant brain regions compared with younger adults. A larger number of studies have examined the plasticity changes of brain from the perspective of regional brain activities. However, studies on only regional brain activities cannot fully elucidate the neural mechanisms of reduced cognitive abilities in aging, as multiple regions are integrated together to achieve advanced cognitive function in human brain. In recent years, brain connectivity/network, which targets how brain regions are integrated, have drawn increasing attention in neuroscience with the development of neuroimaging techniques and graph theoretical analysis. Connectivity quantifies functional association or neural fibers between two regions that may be spatially far separated, and graph theoretical analysis of brain network examines the complex interactions among multiple regions from the perspective of topology. Studies showed that compared to younger adults, older adults had altered strength of task-relevant functional connectivity between specific brain regions in cognitive tasks, and the alternation of connectivity are correlated to behavior performance. For example, older adults had weaker functional connectivity between the premotor cortex and a region in the left dorsolateral prefrontal cortex in a working memory task. Interventions like cognitive training and neuro-modulation (e.g., transcranial magnetic stimulation) have been shown to be promising in regaining or retaining the decreasing cognitive abilities in aging. However, only few neuroimaging studies have examined the influence of interventions to old adult's brain activity, connectivity, and cognitive performance. This Research Topic calls for contributions on brain network of subjects in normal aging or with age-related diseases like mild cognitive impairment and Alzheimer's disease. The studies are expected to be based on neuroimaging techniques including but not limited to functional magnetic resonance imaging, Electroencephalography, and diffusion tensor imaging, and contributions on the influence of interventions to brain networks in aging are highly encouraged. All these studies would enrich our understanding of neural mechanisms underlying aging, and offer new insights for developing possible interventions to retain cognitive abilities in aging subjects.

The field of cognitive aging has evolved from a focus on cataloging age-related declines of brain and mind in healthy older people to a focus on interventions aimed at limiting those declines. Intervention research has obtained convincing evidence of the cognitive benefits of aerobic exercise and working memory training. Recently interest has broadened to include interventions that consider the social and physical environment of the aged individual. Examples of this are investigations of training cognitive-motor integration, interventions to reduce loneliness, mindfulness training, and human factors-based approaches to cognitive deficits. Such approaches move beyond targeting specific abilities in isolation to consider more broadly the overall well-being of the healthy older person. In this Research Topic we call for both empirical and review papers that consider interventions aimed at reducing cognitive and brain aging but also approaches that consider older individuals (animal and human) in their physical and social environment.

Previous studies showed that both healthy and pathological aging are associated with changes in brain structure and function of the mature human brain. The most prominent anatomical alteration are changes in prefrontal cortex morphology, volume loss and reduced white-matter integrity and hippocampal atrophy. Cognitive decline affects mainly the performance of episodic memory, speed of sensory information processing, working memory, inhibitory function and long-term memory. It has been also proposed that due to the aforementioned changes the aging brain engages in compensatory brain mechanism such as a broader activation of cortical regions (mainly frontal) rather than specialized activation. Evidence suggests that similar changes occur with pathological aging but to a greater extent. In this case information flow is disrupted due to neurodegeneration, functional activation of posterior (occipito-temporal) regions is decreased and as a consequence the brain fails to process sensorial input in the ventral pathway and cognitive deficits appear. In the last years, functional alterations associated with aging have been studied using the mathematical notion of graph theory that offers an integrative approach since it examines different properties of the brain network: 1) Organization level 2) amount of local information processing, 3) information flow 4) cortical community structure and 5) identification of functional / anatomical hubs. So, graph theory offers an attractive way to model brain networks organization and to quantify their pathological deviations. Previous studies have already employed this mathematical notion and demonstrated that age-related neurodegeneration is often accompanied by loss of optimal network organization either due to diminished local information processing or due to progressive isolation of distant brain regions. They have also found that changes in network properties may be present even in the preclinical phase, which could be taken as a biological marker of disease.

How we raise young children is one of today's most highly personalized and sharply politicized issues, in part because each of us can claim some level of "expertise." The debate has intensified as discoveries about our development-in the womb and in the first months and years-have reached the popular media. How can we use our burgeoning knowledge to assure the well-being of all young children, for their own sake as well as for the sake of our nation? Drawing from new findings, this book presents important conclusions about nature-versus-nurture, the impact of being born into a working family, the effect of politics on programs for children, the costs and benefits of intervention, and other issues. The committee issues a series of challenges to decision makers regarding the quality of child care, issues of racial and ethnic diversity, the integration of children's cognitive and emotional development, and more. Authoritative yet accessible, From Neurons to Neighborhoods presents the evidence about "brain wiring" and how kids learn to speak, think, and regulate their behavior. It examines the effect of the climate-family, child care, community-within which the child grows.

Traumatic brain injury (TBI) remains a significant source of death and permanent disability, contributing to nearly one-third of all injury related deaths in the United States and exacting a profound personal and economic toll. Despite the increased resources that have recently been brought to bear to improve our understanding of TBI, the development of new diagnostic and therapeutic approaches has been disappointingly slow. Translational Research in Traumatic Brain Injury attempts to integrate expertise from across specialties to address knowledge gaps in the field of TBI. Its chapters cover a wide scope of TBI research in five broad areas: Epidemiology Pathophysiology Diagnosis Current treatment strategies and sequelae Future therapies Specific topics discussed include the societal impact of TBI in both the civilian and military populations, neurobiology and molecular mechanisms of axonal and neuronal injury, biomarkers of traumatic brain injury and their relationship to pathology, neuroplasticity after TBI, neuroprotective and neurorestorative therapy, advanced neuroimaging of mild TBI, neurocognitive and psychiatric symptoms following mild TBI, sports-related TBI, epilepsy and PTSD following TBI, and more. The book integrates the perspectives of experts across disciplines to assist in the translation of new ideas to clinical practice and ultimately to improve the care of the brain injured patient.

Recent studies show that more people than ever before are reaching old age in better health and enjoying that health for a longer time. This Handbook outlines the latest discoveries in the study of aging from bio-medicine, psychology, and socio-demography. It treats the study of aging as a multidisciplinary scientific subject, since it requires the interplay of broad disciplines, while offering high motivation, positive attitudes, and behaviors for aging well, and lifestyle changes that will help people to stay healthier across life span and in old age. Written by leading scholars from various academic disciplines, the chapters delve into the most topical aspects of aging today - including biological mechanisms of aging, aging with health, active and productive aging, aging with satisfaction, aging with respect, and aging with dignity. Aimed at health professionals as well as general readers, this Cambridge Handbook offers a new, positive approach to later life.