On the one hand, the dismal thought that the human brain gradually loses tissue from age 30 onward and the projected rapid growth of an aging population present society with numerous public policy issues regarding the staggering costs of geriatric care. On the other hand, the good news is that advanced research in neuroscience tells us that this is an oversimplification of what happens to the aging brain. Of importance to policymakers is to realize that researchers are identifying ways in which such cerebral deterioration can be reduced or even reversed. In addition, researchers have identified areas of the brain that are relatively preserved and may even show growth. Thus, it is important for policymakers to obtain a more complete picture of aging.
Research in neuroscience and aging is extremely important, not only for health care policies, but also for the psychological and physiological well-being of the aging adult. The mission of the National Institute on Aging has focused much of its efforts onto biomarkers of healthy aging, demanding more interdisciplinary work in this area. Whereas behavioral research alone has been sufficient to move our understanding of aging forward, it is critical to incorporate all levels of understanding, including the neurological/biological aspects, in future work. A good example is the compelling findings regarding aerobic exercise and aging. The use-it-or-lose-it model of aging has reached new heights. We are not only talking about weight loss with respect to aerobics, but now we are talking about extending the vitality of older adulthood. Finally, evidence showing that emotional brain functions may improve with age provides a platform from which new interventions might be developed to draw on strategies of emotional control to better cope with any declines in functioning.
Summary
2.1 The Neuroscience Approach
How do the basic developmental forces
benefit from the neuroscience approach?
• The neuroscience approach adds to the converging evidence on how interventions at the social, biological, and psychological level influence positive and negative change as we grow older.
What is the major focus of the neuropsychological approach to neuroscience?
• The neuropsychological approach compares brain-related psychological functioning of healthy older adults with adults displaying pathological disorders in the brain.
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Describe the difference between the correlational approach and the activation imaging approach to studying neuroscience.
• The correlational approach links measures of behavioral performance to measures of neural structure or functioning.
• The activation imaging approach directly links functional brain activity with behavioral data.
What is the difference between MRI and fMRI scanning?
• MRI is a noninvasive technique producing images of the brain’s structure.
• fMRI focuses more on the functioning of the brain.
2.2 Neuroscience and Cognitive Aging
What are the basic structural changes in the brain as we age?
• There is considerable shrinkage that occurs in the aging brain, but it is selective and differential.
• The white matter of the brain shows deterioration with increasing age.
What cognitive functions are associated with volume shrinkage in the aging brain?
• Volume shrinkage in the brain is linked to poor cognitive performance such as executive functioning, which has been associated with decreased volume of the prefrontal cortex.
• Comparisons of structural changes in Alzheimer’s patients with those of healthy aging adults have revealed that deterioration of the medial-temporal area influences memory performance.
How do decreases in the dopaminergic system relate to changes in cognitive functioning as we grow older?
• Using a neuropsychological approach, studies find that the overall efficacy of the dopaminergic system declines in normal aging.
• Dopaminergic receptors are related to higher-order cognitive functioning such as the regulation of attention.
What happens to brain activation as we age?
• Frontal lobe theory suggests that many age-related declines in cognitive functioning are a function of insults to the frontal lobes.
• Cognitive decline is associated with reduced activation of neurons in prefrontal and medial-temporal areas supporting memory and other cognitive functions.
• Brain activation reveals under-recruitment of the prefrontal cortex during performance on cognitive tasks.
What are the cultural implications of neuroimaging?
• Neuroimaging evidence suggests that there are cultural biases in perceptual processing. However, age-related change has a more profound effect on changes in the brain than culture.
Neuroscience as a Basis
How does bilateral activation serve a functional role in older adults’ cognitive functioning?
• The neural patterns of younger and older
adults differ significantly. Whereas younger adults’ brain activity is localized in one hemisphere of the brain, older adults’ brain activity appears in both hemispheres or more than one location.
• Bilateral activation in older adults may serve a supportive role in their cognitive functioning.
What are the major differences between the HAROLD and STAC models of brain activation and aging?
• The HAROLD model suggests that the bilateral activation found in older adults is compensatory in that additional neural units are recruited to increase resources.
• The STAC model suggests that the reason older adults perform at high levels despite neuronal deterioration is because of compensatory scaffolding or the recruitment of additional circuitry to bolster functional decline. However, this model further states that compensation is the brain’s response to challenge in general.
2.3 Neural Plasticity and the Aging Brain
How do animal models contribute to our understanding of neural plasticity and aging?
• Even though aging is associated with a striking decrease in the number of new neurons, this may be altered even at advanced ages.
• Even in advanced stages of aging, the brain retains its capacity to react to external stimuli that are related to improved cognitive performance.
What evidence is there for neural plasticity in aging humans?
• Positive biochemical changes in healthy older adults were observed after five weeks of training using method of loci mnemonic strategies to improve memory.
• Although neural plasticity is present across the adult life span, there are age-related reductions in this plasticity and the potential for functional improvement.
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How does aerobic exercise influence cognitive aging?
• Higher levels of aerobic fitness are associated with the preservation of the hippocampus (involved in learning and memory) in older adults.
2.4 Neuroscience and Socio-Emotional Aging
Are there differences in the brain for cognitive versus socio-emotional functioning?
• Areas such as the temporal cortex, amygdalae, and basal ganglia are associated with automatic social cognitive processes and emotional processing. This area seems to be relatively spared with aging.
• The neural basis of a more deliberative social cognition is in the prefrontal cortex, anterior cingulate, and hippocampus. These areas show the most deterioration with aging.
What is the neural circuitry responsible for enhanced memory for emotional information?
• There are two distinct neural processes that contribute to emotional memory: the amygdalae, which is linked to the processing of negative high-arousal information, and the prefrontal cortex-hippocampus network, which is implicated for memory processing.
• Increased activation in these areas corresponds to remembering negative high — versus low-arousal information.
What are the neural underpinnings of the positivity effect found in older adults?
• The brain areas associated with emotional processing undergo relatively modest structural changes with aging. This is described as the core emotional memory network.
• Neuroimaging studies reveal that when older adults are presented with positive information, different areas of the brain are activated in comparison to younger adults (e. g., the medial prefrontal cortex and regions of the cingulated gyrus).
• Changes in the positivity effect may also arise from better emotion regulation.
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Review Questions
2.1 The Neuroscience Approach
• Describe the three neuroscience methodological perspectives used to study the aging brain. What are their strengths and limitations?
• What are the major differences between MRI and fMRI scanning techniques?
• How does the neuroscience level of examination contribute to our understanding of adult development and aging?
2.2 Neuroscience and Cognitive Aging
• Describe the basic structural changes in the aging brain.
• What changes are observed in cognitive functions that are associated with volume shrinkage in the brain?
• What happens to dopamine functioning in the aging brain?
• What are the differences in brain activation during cognitive tasks for younger and older adults?
• How does bilateral activation serve an adaptive function for older adults?
• Describe the HAROLD, CRUNCH, and STAC models of brain activation and aging.
2.3 Neural Plasticity and the Aging Brain
• What can animal models tell us about neural plasticity in the aging brain?
• Does aerobic fitness improve cognition as we grow older?
2.4 Neuroscience and Socio-Emotional Aging
• How does the brain operate differently for cognitive versus socio-emotional processing?
• What are the brain structures underlying the enhancement of emotional information in memory?
• What is the positivity effect? What is the neuroscience evidence for this phenomenon?
Integrating Concepts in Development
• Which of the theories of bilateral activation in older adults’ brains makes the most sense to you? Why?
• What would you say about the stereotypes of aging now that you understand the plasticity of brain functioning?
• What does the work on brain plasticity imply for exercising the mind and body?
• How does the research on neuroscience and cognition compare to the behavioral research on cognition and aging in Chapter 6?
• How does the research on neuroscience and socio-emotional functioning compare to the behavioral research discussed in Chapter 8?
Key Terms
activation imaging approach Attempts to directly link functional brain activity with cognitive behavioral data.
Alzheimer’s disease A disease commonly found in the elderly that is characterized by a decline in memory and a progressive destruction of brain cells. amygdala The region of the brain, located in the medial- temporal lobe, believed to play a key role in emotion. anterior cingulate Located in the front part of the cingulated cortex, this region of the brain plays a role in autonomic functions, cognitive functions, and emotion.
basal ganglia A group of nuclei interconnected with the cerebral cortex. They are associated with motor control, cognition, and emotions. bilateral activation Involves activation of a specific brain structure in both lateral hemispheres of the brain. cerebellum The part of the brain that is associated with motor functioning and balance equilibrium. compensatory Involves the use of a behavior or function to aid in performance that has been otherwise compromised.
controlled self-generated encoding When individuals elaborate on information by relating it to themselves and rehearse the information in this way. correlational approach Attempts to link measures of cognitive performance to measures of brain structure or functioning.
default network The regions of the brain that are most active at rest.
diffusion tensor imaging The measurement of the diffusion of water molecules in tissue in order to study connections of neural pathways in the brain. dopaminergic system Involves dopamine neurotransmission. Dopamaine is a neurotransmitter and is critically implicated in multiple cognitive functions.
environmental enrichment In animal studies, involves raising animals in large groups filled with changing arrangements of toys/objects. executive functions Include the ability to make and carry out plans, switch between tasks, and maintain attention and focus.
functional imaging (e. g., fMRI) Examines how changes in brain activity occur in correspondence to changes in task demands and the type of cognitive functioning under investigation. hippocampus Located in the medial-temporal lobe, this part of the brain plays a major role in memory and learning.
lateral occipital complex A highly specialized neural site involved in processing the face, place, and object areas. method of loci A memory technique for remembering things by linking them to places. neostriatum Receives input from the cerebral cortex and other brain areas and provides output to the basal nuclei.
neural stem cells Those that give life to new neurons throughout the life span. neuropsychological approach Compares brain functioning of healthy older adults with adults displaying various pathological disorders in the brain. over-recruitment Occurs when additional neurons fire and shore up declining brain structures that are inefficient.
Parkinson’s disease A brain disease caused by an extreme drop in the neurotransmitter dopamine. plasticity Involves the interaction between the brain and the environment and is mostly used to describe the effects of experience on the structure and functions of the neural system. positivity effect When an individual remembers more positive information relative to negative information.
63 prefrontal cortex (PFC) Part of the frontal lobe that is involved in executive functioning. selective allocation of attention When something in the environment captures one’s attention and the individual allocates more resources in the attention to that item.
supplementary processes When different brain regions are activated to compensate for lacking processing resources.
under-recruitment Occurs when neuronal firing is limited when the brain is activated. ventromedial prefrontal cortex (VMPFC) Part of the prefrontal cortex, this may be involved in decision making and processing risk.
white matter hyperintensities (WMH) Abnormalities in the brain often found in older adults; correlated with cognitive decline.
working memory performance Holding and manipulating information in consciousness.
Resources
www. cengage. com/psychology/cavanaugh
Visit the companion website, where you will find tutorial quizzes, glossary, flashcards, and more. You can also access the following websites from the companion website.
The National Institute on Aging (NIA) publishes informative brochures on neuroimaging and brain plasticity as well as a focus on social neuroscience and cognitive neuroscience and aging. These are all based on scientific findings.
Center for Cognitive and Social Neuroscience at the University of Chicago is a leading resource for information on events, resources, and brain and behavior research. Their website provides a wide variety of information and resources and summaries of legislative and advocacy activities.
The Society for Neuroscience is another good source of the latest research on neuroscience and aging and brain facts.
Readings
Baltes, P. B., Reuter-Lorenz, P, and Rosler, F. (2006). Lifespan Development and the Brain: The Perspective of Biocultural Co-Constructivism. New York: Cambridge University Press. A comprehensive collection of chapters on plasticity of numerous areas of the brain. Moderate to difficult reading.
Cabeza, R., Nyberg, L., and Park, D. (2005). Cognitive Neuroscience of Aging: Linking Cognitive and Cerebral Aging. U. S.: Oxford University Press. A compilation of chapters on cognitive neuroscience and aging. Moderate reading.
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THE SUMMER OLYMPICS HELD IN BEIJING IN 2008 WERE SPECIAL FOR MANY
reasons. Among the most important were accomplishments and milestones in swimming. Michael Phelps set the record for most gold medals won in a single Olympics (8) and overall (14). At age 23, he had reached the highest level of performance for a male swimmer. Phelps epitomizes the fact that most world-class amateur and
professional athletes reach their peak in their twenties. Then there are people who rewrite our beliefs about athletic performance. At the same competition, Dara Torres was competing in her fifth Olympics. As we noted in Chapter 1, she became, at age 41, the oldest swimmer ever to win an Olympic medal (she won three silver medals), and one of only a few who have won medals in five different Olympic games. Middle — aged adults everywhere were thrilled that someone who traditionally
would have been written off as too old defeated women less than half her age.
What’s ahead for Michael Phelps and Dara Torres? Although we can’t predict how many and which events they will win over the coming years, or how long they will continue to compete, it is clear that our beliefs about physical performance are undergoing change. To be sure, athletic success is a combination of years of intense practice and excellent genes. But before Beijing, no one would have thought that a middle-aged woman could compete at that level.
Phelps and Torres represent the best. What about the rest of us? In this chapter, we will discover how physical abilities typically change across adulthood. What makes Phelps and Torres (and other world-class amateur and professional athletes) different is that because they stay in great physical condition, the normative changes tend to happen more slowly.
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