The Aging Mind Opportunities in Cognitive Research (2000) / Chapter Skim
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4 Structure of the Aging Mind
4 Structure of the Aging Mind
Pages 37-53
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From page 37... ...
It is now possible to make significant progress in this direction. Improvements in measurement of cognitive and neural functioning, new methods of analyzing the data, and an expansion of longitudinal research now make possible substantial improvement in understanding the nature of cognitive aging, including the identification of mechanisms at the behavioral and neural levels that contribute to age-related changes and to differences between individuals and groups.
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From page 38... ...
Schaie's data are from psychometric tests that were not designed to identify mental processes and mechanisms underlying the cognitive functions being measured. Using laboratory techniques from cognitive psychology to investigate semantic memory processes, studies consistently report age invariance in semantic organization and processes, and in a variety of other language processes (see Kemper, 1992; Light, 1991; Burke, 1997~.
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From page 39... ...
, may be explainable in part in terms of change in sensory-motor and health status, as discussed in the next section. Modulation of Cognitive Aging by Experience The trajectories of cognitive aging are not the same for all individuals, even for highly specific cognitive functions.
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From page 40... ...
. Further investigation of the effect of the mechanisms that link experiential factors on cognitive aging promises to increase our understanding of the mechanisms involved in age-related cognitive changes.
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From page 41... ...
For instance, if sensory-motor decline causes cognitive decline, then aids to sensory-motor performance might protect against, or even reverse, cognitive decline. Hypotheses about common causes of sensory-motor and cognitive decline in old age call into question the common practice of treating sensory, motor, and cognitive systems as discrete systems underlying behavior (see Schneider and Pichora-Fuller, in press)
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From page 42... ...
Cognitive Effects of Changes in Health Status It has been proposed by some that age-related cognitive decline in many individuals is attributable to disease processes that affect the nervous system only indirectly, including cardiovascular diseases and diabetes, among others (Salthouse et al., 1990; Waldstein, Appendix E)
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From page 43... ...
Numerous possible causal mechanisms may explain correlations between disease conditions and particular types of cognitive functioning, and research is just beginning in this area. In addition to having some potential to illuminate some of the causes of cognitive decline, this line of research brings an added benefit: it can strengthen research on other aspects of cognitive aging by promoting controls for health conditions and interpretations that take such conditions into account.
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From page 44... ...
Developments in Measurement and Theory Growing sophistication in theoretical understanding of cognitive functions, advances in measurement of neural phenomena and cognitive functions, and the availability of analytic techniques from related fields are making possible new advances in explaining the patterns of cognitive aging and linking changes in cognitive function to changes in the brain. Improved Measurement of Neural and Cognitive Phenomena Advanced neuroimaging and electrophysiological techniques for measuring on-line brain function, such as functional magnetic resonance imagery (fMRI)
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From page 45... ...
For example, experimental techniques have been used to demonstrate the distinct neural bases of implicit versus explicit memory in cognitive neuroscience research with patients (e.g., Gabrieli et al., 1995; Shimamura and Squire, 1984) and using imaging techniques (e.g., Uecker et al., 1997~.
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From page 46... ...
As neuroscience research attains higher levels of resolution, it will become possible to identify particular neural circuits believed to be associated with particular cognitive functions. To achieve understanding of brain-behavior links at this level, it is important to build theory and to identify or construct behavioral measures that fit the structure of cognition and can be localized with comparable resolution to neural observations.
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From page 47... ...
Four of these are dynamical systems theory, hidden Markov models, connectionist models, and dynamic factor analysis. Dynamical systems theory characterizes the properties of different patterns of stable behavior, as well as transitions among such patterns.
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From page 48... ...
These models include various approaches known as neural networks, neural models, parallel distributed processing systems, localist models, and spreading activation models, and have in common a network of nodes connected by weighted pathways. Connectionist models are sensitive to biological constraints, as nodes can be loosely associated with neurons and their connections with synapses.
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From page 49... ...
The connectionist approach has been extremely useful in cognitive research, producing better theoretical understanding of brain function and cognitive processes and generating hypotheses about mechanisms underlying important cognitive behaviors. It has led to the identification of fundamental principles of cognitive processing, such as the necessity of parallel processing to achieve the computational power required for cognition, and it has provided a means for both generating and evaluating hypotheses about the functional deficits that underlie cognitive disorders.
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From page 50... ...
It has also revealed that in advanced old age, the correlations increase among measures of different cognitive functions. Furthermore, research has linked a variety of experiences to cognitive performance in older adults, including physical exercise, diet, cognitive training, expertise, and the provision of environmental support; it has also documented relationships of cognitive functions to body systems, including sensory-motor functioning and chronic diseases.
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From page 51... ...
Recent advances in the behavioral measurement of specific cognitive functions have already been noted. The research initiative should support studies to identify or develop focused behavioral indicators that connect closely to high-resolution neural observations.
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From page 52... ...
The research initiative should support theory-driven research that develops models of cognitive aging effects that will increase our understanding of patterns of stability and change among mental processes in the aging mind, as well as complex interactions among cognitive and other systems. Existing findings from cognitive aging research provide a wealth of data that demonstrate both impaired and preserved cognitive functions in old age.
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From page 53... ...
The conjunction of improved measurement, advances in modeling, and the comprehensive collection of longitudinal data on cognitive functioning and associated factors can have a synergistic effect in advancing knowledge. Longitudinal studies can make a quantum improvement by employing new fine-grained neural and behavioral measures; renewed attention to modeling can make better sense of the patterns that underlie associations between these neural and behavioral measures and that can be drawn from the longitudinal data.
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