PSYC 381 Chapter Notes - Chapter 2: Diffusion Mri, Functional Neuroimaging, Hyperintensity
14 Jun 2018
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Describe the two types of neuroimaging techniques and the value of each. Why are
these techniques important? (pp. 34-35)
1. Structural neuroimaging. This provides highly detailed images of anatomical
features in the brain. The most commonly used ones are X-rays, CT scans and
MRI's. Can detect bone fractures or tumours
2. Functional neuroimaging. Provides an indication of brain activity but not high
anatomical detail. The most commonly used techniques are PET scans or fMRI. A
typical image will show different levels of brain activity as different colours.
Are important because it has proven that age related brain changes are
responsible for age related changed in performance. Research has shifted from
describing brain activation patterns to explaining them. Help improve quality of
life.
1.
Compare and contrast the three neuroscience perspectives, and explain how they
promote theoretical development in the field of aging. (pp. 35-36)
1. Neuropsychological approach. This approach compares brain functioning of
healthy older adults with adults displaying various pathological disorders in the
brain. Researchers are interested in whether patients of any age with damage in
specific regions of the brain show similar cognitive deficits to those shown by
healthy older adults.
2. Neurocorrelational approach. Attempts to relate measures of cognitive
performance to measures of brain structure or functioning. Instead of direct
measures of brain structure or functioning, some researchers using this approach
investigate the correlation between behavioural tests that are associated with
the function of specific brain regions.
3. Activation imaging approach. Attempts to directly link functional brain activity
with the cognitive behavioural data. This approach relies on functional
neuroimaging techniques, such as fMRI.
These approaches promote theoretical development in the field of aging because
they make it easier to understand the neuroscience of aging. They give multiple
perspectives and approaches to understanding the development of aging.
2.
Summarize the major age-related changes in brain structure, and describe how
these changes have been linked to cognitive and emotional function. Be sure to
include a description of white matter hyperintensities and diffusion tensor
imaging. (pp. 37-44)
• The major age-related changes in brain structure include an average overall
deterioration in certain brain structures in both size and density.
• Some of these structures that tend to shrink over the lifespan include the
prefrontal cortex, the hippocampus, and the cerebellum.
• Another area of the brain that may decline or deteriorate over the lifespan are
white matter tracts.
White matter are neurons covered by a myelin sheath that function to
transmit information from one portion of the cerebral cortex to another,
or to other portions of the brain.
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• As humans age, our white matter shrinks and becomes less dense, and in turn
declines our overall health.
• Diffusion tensor imaging evaluates the direction and rate of water diffusion
through the white matter of the brain. Using diffusion tensor imaging, studies
examining white matter hyperintensities have demonstrated that the
deterioration of white matter in the brain may be a cause of increased prefrontal
cortex dysfunction in older adults.
• Poor performance on executive functioning tasks has been associated with
decreased volume in the prefrontal cortex.
• Older adults tend to regulate emotions better than younger adults.
• Brain structures involved in more automatic processing (amygdala) show less
age related deteriorating, whereas those involved in mote reflective processing
(prefrontal cortex) show more severe deterioration.
This concludes that older adults may rely more on automatic processes.
3.
Describe the age-related changes in neurons and neurotransmitters in brain
neurochemistry and their relation to cognitive function. What are the functional
consequences of brain deterioration? (pp. 38-39)
• As we age, the number of neurons in the brain declines and structural changes
happen.
• Decreases in the size and number of dendrites, as well as the number of
potential connections.
• Declines in the dopaminergic system are related to declines in different aspects
of memory.
• Abnormal processing of serotonin has been shown to be related to cognitive
decline both in normal aging and other disorders.
• Acetylcholine has a role in arousal, sensory perception and sustaining attention.
Damage to these neurotransmitters cause serious memory loss.
Major consequence to brain deterioration would be memory loss. The same
changes that occur in our brain when we age, are the same changes that occur In
Alzheimer patients but more extreme. It all has to do with the speed and number
of changes, not in the kind of changes that occur.
4.
Describe the Parieto-Frontal Integration Theory. What is bilateral activation, and
what role does it play in the HAROLD model? Describe the CRUNCH Model and
the STAC model. How do these models differ from each other? (pp. 45-50)
The Parieto-Frontal Integration theory proposes that intelligence comes from a
distributed and integrated network of neurons in the parietal and frontal areas of
the brain. Research has shown that the prefrontal cortex connects to the limbic
system and the amygdala, which influence how we process emotional content.
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Bilateral activation happens in older adults and is activation of both sides of the
prefrontal cortex. This happens because older adults are compensating for lost
neurons.
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The Harold model stands for Hemispheric Asymmetry Reduction in OLDer adults.
It explains the reduced ability of older adults to separate cognitive processing in
different parts of the prefrontal cortex.
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The Crunch model stands for Compensation-Related Utilization of Neural Circuits
Hypothesis. This model describes how the aging brain adapts to neurological
decline by recruiting additional neural circuits. It has the same concepts as Harold
model, except instead of just bilateral thinking it uses two additional processes as
well. The first one is called more of the same, which means it activates more of
the same brain region. The second is called supplementary processes which
means different brain regions are activated to compensate for lacking or
insufficient processing.
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The STAC model is based on the idea that age-related changes in ones ability to
function reflect a life long process of compensating for cognitive decline by
recruiting additional brain areas. In older adults, they struggle to suppress the
default network of the brain (regions of the brain that are most active when one
is at rest). Older adults create and rely on a back up neural pathways. It displays
that the brain can change and adapt to new ideas.
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5.
What is neural plasticity? What are neural stem cells? Describe the evidence that
supports plasticity. How do exercise and nutrition affect brain aging, and how are they
related to plasticity? (pp. 50-52)
• Neural plasticity is changes in the structure and function of the brain as the
result of interaction between the brain and environment.
• This shows that basic cognitive processes affected by aging can indeed be
improved through training.
• Neural stem cells are cells that persist in the adult brain and can generate new
neurons throughout the life span. You can teach your brain new things and it will
remember it.
• Brain plasticity is enhanced through aerobic exercise. Higher aerobic fitness
level is associated with the preservation of greater hippocampal volume.
• Higher vitamin B,C,D and E, and other omega 3 fatty acids was associated with
better cognitive functioning.
• Only EPA acid (omega 3) was associated with better neuro structure in the right
part of the amygdala.
6.
L2 -Neuroscience & Aging
Tuesday, May 22, 2018
11:18 AM
Document Summary
Describe the two types of neuroimaging techniques and the value of each. This provides highly detailed images of anatomical features in the brain. The most commonly used ones are x-rays, ct scans and. Can detect bone fractures or tumours: functional neuroimaging. Provides an indication of brain activity but not high anatomical detail. The most commonly used techniques are pet scans or fmri. A typical image will show different levels of brain activity as different colours. Are important because it has proven that age related brain changes are responsible for age related changed in performance. Research has shifted from describing brain activation patterns to explaining them. Compare and contrast the three neuroscience perspectives, and explain how they promote theoretical development in the field of aging. (pp. This approach compares brain functioning of healthy older adults with adults displaying various pathological disorders in the brain.
