3. The Neuroscience Approach
Learning Objectives
• How do the basic developmental forces benefit from the
neuroscience approach?
• What is the major focus of the neuropsychological
approach to neuroscience?
• Describe the difference between the correlational
approach and the activation imaging approach to
studying neuroscience.
• What is the difference between MRI and fMRI
scanning?
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4. The Neuroscience Approach
Implications of the Developmental Forces
• Age is not the best predictor of behavior.
• Behavior is determined by multiple forces.
• Cognitive - Social – Emotional
• Structural changes in brain volume and density
• Functional changes in brain areas
• Brain plasticity
• Environmental interventions on structure and activation
of the brain
• Social, biological, and psychological interventions to
influence positive changes
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5. The Neuroscience Approach
Neuroscience Tools
• Magnetic resonance imaging (MRI)
• Functional magnetic resonance imaging (fMRI)
• MRI provides static snapshots of the brain
• fMRI monitors dynamic activities of the brain concurrent
with behavioral performance
• Allows study of age related pathologies
• Alzheimer’s
• Parkinson’s
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6. The Neuroscience Approach
Neuroscience Perspective
• Methodological Perspectives
• Neuropsychological
• Compares healthy older adults with those with pathological
disorders of the brain
• Correlational
• Links measures of cognitive performance to measures of
brain structure or functioning
• Activation imaging
• Links functional brain activity with cognitive behavior data
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8. Neuroscience and Cognitive Aging
Learning Objectives
• What are the basic structural changes in the brain as
we age?
• What cognitive functions are associated with volume
shrinkage in the aging brain?
• How do decreases in the dopaminergic system relate to
changes in cognitive functioning as we grow older?
• What happens to brain activation as we age?
• What are the cultural implications of neuroimaging?
• How does bilateral activation serve a functional role in
older adults’ cognitive functioning?
• What are the major differences between the HAROLD
and STAC models of brain activation and aging?
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9. Neuroscience and Cognitive Aging
Structure of the Brain
• Anatomy of the human brain
• Executive functions
• Ability to make and carry out plans
• Switch between tasks
• Maintain attention and focus
• Age-Related Changes in the Structure of the Brain
• Thinning and shrinkage in volume and density
• White matter hyperintensities (WMH)
• Indicates myelin loss or neural atrophy
• Diffusion tensor imaging (DTI)
• Index of density or structural health of the white matter
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10. Neuroscience and Cognitive Aging
Structure of the Brain
• How deteriorating structural changes relate to cognitive
function
• Less efficient information processing
• Speed of processing
• Executive functions
• Declarative long-term memory
• Volume shrinkage in the brain linked to:
• Lower cognitive test scores
• Poor performance of executive function which is also linked
to:
• Decreased volume of prefrontal cortex
• Memory decline
• Frontal volume as predictor of cognitive function has
yielded inconsistent findings.
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11. Neuroscience and Cognitive Aging
Structure of the Brain
• Studies in structural changes in the aging brain and cognitive
functions has overall produced inconsistent findings.
• However, inconsistencies can be attributed to:
• Sample composition
• Whether cross-sectional differences or longitudinal
changes are being examined
• Whether different subregions are under investigation
• Whether different cognitive test are used
• Regardless, when longitudinal converge with cross-sectional
studies, it is clear that increases in WMH are associated with
reduced performance on executive functioning tasks.
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12. Neuroscience and Cognitive Aging
Age-Related Changes in Neurochemical Properties
• The dopaminergic system is associated with:
• Higher–level cognitive functioning
• Inhibiting thoughts
• Attention
• Planning
• Declines in dopamine system are related to declines
in:
• Episodic memory
• Speed tasks
• Age-related deficits in working memory
• Declines in memory
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13. Neuroscience and Cognitive Aging
Age-Related Changes in Brain Activity
• Functional imaging (fMRI) examines how:
• Changes in brain activity are related to:
• Changes in task demands
• Type of cognitive functioning under investigation
• Do older adults compared to younger adults use
different areas of the brain in order to perform
cognitive tasks more effectively?
• Is this a method of adaptive accommodation by the brain in
order to assist older adults to adjust to neurological
impairment brought about by increasing age?
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14. Neuroscience and Cognitive Aging
Functional Consequences of Brain Deterioration
• Anterior cingulate cortex (ACC)
• Affiliated with the prefrontal cortex and is also involved in
executive control
• Reduced working memory performance is related to
decreased activation of the ACC in older adults.
• Reduced brain activation (under-recruitment) of the
prefrontal cortex occurs during intentional cognitive
processing.
• Reduced frontal recruitment in aging is context-dependent.
• Other studies show equal frontal activity in older and
younger adults in memory retrieval.
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15. Neuroscience and Cognitive Aging
Culture, Neuroimaging, and Aging
• Examining cultural differences in neurobiological aging
• Older adults in from Western cultures show significantly
greater object-processing adaptation in the lateral occipital
complex, relating visual processing, than older East Asians.
• Overall, however, age-related changes seem to be more
profound than cultural effects.
• Different regions of the brain do not deteriorate evenly.
• Prefrontal area is more prone to decay than, for example, the
amygdala (involved in emotional processing).
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16. Neuroscience and Cognitive Aging
Compensation and Prefrontal Bilaterality
• Studies show that, when presented with similar tasks,
younger adults exhibit focal, unilateral activity in left
prefrontal region and older adults exhibit bilateral
activity (both left and right prefrontal areas).
• Why? Is it compensation for deterioration in older brains or is it
inefficient inhibitory mechanisms?
• Growing body of evidence supports the theory that bilateral
activation in older adults plays a supportive role in their
cognitive function. (see fig, 2.2)
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17. Neuroscience and Cognitive Aging
Compensation and Prefrontal Bilaterality
• STAC (scaffolding theory of cognitive age)
• Default network theory holds that when the cognitive demands
are made on the brain the default network is suppressed.
- Increased demand scaffolds increase areas of the brain.
• HAROLD (hemispheric asymmetry reduction in older
adults.
• Suggests bilaterality is compensatory in older adult with
reduced cognitive ability
• CRUNCH (compensation-related utilization of neural
circuits hypothesis)
• This hypothesis is similar to HAROLD but suggests additional
mechanisms at work of aging brains over-utilizing other regions
in the left hemisphere on demanding tasks before going to the
right hemisphere.
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19. Neural Plasticity and the Aging Brain
Learning Objectives
• How do animal models contribute to our understanding
of neural plasticity and aging?
• What evidence is there for neural plasticity and aging?
• How does aerobic exercise influence cognitive aging?
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20. Neural Plasticity and the Aging Brain
• Plasticity involves the interaction between the brain and the
environment and is mostly used to describe the effects of
experience on the structures and function of the neural system.
• Neural stem cells (which give rise to new neurons) persist in adult
brains and can generate new cells throughout adulthood.
• Environmental enrichment – Experiments with aging mice showed
the increased number of newly generated neurons after sessions on
complicated mazes.
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22. Neuroscience and Socio-Emotional Aging
Learning Objectives
• Are there differences in the brain for cognitive versus
socio-emotional functioning?
• What is the neural circuitry responsible for enhanced
memory for emotional information?
• What are the neural underpinnings of the positivity
effect found in older adults?
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23. Neuroscience and Socio-Emotional Aging
Emotional Processing and the Brain
• Information with high emotional significance is more
likely to be remembered than information that is
emotionally neutral for both older and young adults.
• Negative high-arousal information is:
– automatic in nature
– linked to activation of the amygdala interacting with the
hippocampus
• Negative low-arousal information:
– more activation of the prefrontal cortex-hippocampus network
is necessary
• If the amygdala is damaged, arousing stimuli are not
attended.
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24. Neuroscience and Socio-Emotional Aging
Aging and Emotional Processing
• Younger and older adults process positive and negative
information differently.
– Older adults are more motivated to derive emotional meaning
from life and to maintain a positive affect.
– As a result, older adults pay attention and remember positive
more than negative information.
– Younger adults tend to pay attention and remember negative
more that positive information.
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25. Neuroscience and Socio-Emotional Aging
Neurological Recruitment Underlying the Positive Effect in
Memory
• Core emotional memory network consists of the:
– amygdala
– hippocampus
– lateral orbitofrontal cortex
• In older adults, these areas are relatively well preserved in
emotional memory and correspond to memory performance in
both positive and negative items.
• In both older and younger adults, the occipito-temporal regions
(specifically the fusiform gyrus) are used for successful encoding
of negative information.
• Positive information activates the anterior prefrontal regions.
• Older adults show activation of the medial prefrontal cortex and
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26. Neuroscience and Socio-Emotional Aging
Neurological Recruitment Underlying the Positive Effect in
Memory
• The positivity effect should be seen only when an individual has a
high degree of cognitive control resources.
– Older adults who are low in cognitive resources show no positivity
effect.
• Young and old adults show different brain activation when viewing
faces with negative emotional expressions.
– Young adults show increased activity in the amygdala when viewing
negative emotional expressions compared to older adults.
– Older adults do show increased activity in the anterior cingulate gyrus
when viewing negative emotional expressions.
• Research reveals the core emotional memory networks is
preserved with aging. Age differences are found in encoding
positive and negative information.
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