7 - The aging brain

Question 1

Name the 4 lobes.

Answer 1

1) Frontal lobe
2) Parietal lobe
3) Temporal lobe
4) Occipital lobe

Question 2

Explain the role of the frontal lobe.

Answer 2

• Its main role is executive functioning, along with decision making, planning, imagining the future
• Motor cortex: movement
  → part of the frontal cortex
  → helps to plan, control and execute voluntary movement
  → the point where the motor cortex and the somatosensory cortex meet is the central sulcus – forms a boundary between the frontal and the parietal lobes

Question 3

Explain the role of the parietal lobe.

Answer 3

• Directs goal orientated movement
  → p.ex: grasping an object
• Somatosensory cortex: sensory information
  → p.ex: temperature, taste, touch, movement from the rest of the body

Question 4

Explain the role of the temporal lobe.

Answer 4

• Hearing, language, and music
• lies below the lateral fissure (boundary between the temporal and the frontal and parietal cortex)
• the underside of each temporal lobe plays a crucial role in memories

Question 5

Explain the role of the occipital lobe.

Answer 5

• Visual processing
  → processes imagines from the eyes and links that information to images stored in memory

Question 6

What are the largest and second largest parts of the brain?

Answer 6

1) Cerebrum: This is the 4 lobes
2) Cerebellum: Processes and regulates signals between other parts of the brain and body

Question 7

What are the 3 ways we talk about the brain (its orientation)?

Answer 7

1) Anterior vs. Posterior (front vs. back)
2) Lateral vs. medial (sides vs. middle)
3) Dorsal vs. Ventral (top vs. bottom)

Question 8

What is white matter?

Answer 8

• Part of the brain’s composure
• Is made up of nerve fibres and forms tracts that send information through the brain
• Made up of bundles of axons (which also gives it its white colour)
• Wrapped in myelin which gives the tissue its white colour (axons pathways) and provides insulation for the axon and helps nerve signals travel faster and farther (signal transmission)
• Axons may be short (like signals from one cell to another), and its less than a hair-width away; or can be very long (signals from the brain all the way down the spinal cord)
• Makes up 60% of the brain

Question 9

What is grey matter?

Answer 9

• Part of the brain’s composure
• Is made up of cell bodies and is where processing of information occurs
• The dendrites receive messages from other cells
  → dendrites: end portion of nerves
  → they extend out of the cell body like the branches of a tree and receive these messages
  → signals pass from the dendrites through the cell body and may travel away from the cell body down an axon or axon terminals then to another neuron
• Is grey because that section of the nerve lacks the fatty material called myelin
• The cerebral cortex (or gray matter) makes up the outer layer of the brain
  → these are the 2 ways we can refer to the outer layer
• 40% of the brain

Question 10

What are ventricles?

Answer 10

• Part of the brain’s composure
• Filled with cerebrospinal fluid (CSF) which cushions the brain and spinal cord
  → CSF is manufactured in the ventricles, which allows the brain to move and expand without pushing too much on the skull
  → CSF washes out waste and impurities and delivers nutrients
  → measure of atrophy, because as grey matter shrinks, the ventricles get larger
  → white space in the middle: for people with dementia, this space expands, which means you have less grey and white matter, but more CSF

Question 11

___ matter deals with signal transmission, while ___ matter deals with information processing.

Answer 11

White; grey

Question 12

Numerous changes in the brain are observed in aging including..

Answer 12

→ Decreased white and gray matter volume
→ Alterations in functional connectivity
→ Increases in vascular lesions
→ Changes in protein composition
→ Reductions in neural activity and blood flow

Question 13

What are reductions in white matter with age attributed to (structural brain changes)?

Answer 13

Reductions in white matter with age are attributed to factors such as myelin degeneration, axonal loss, and reduce white matter integrity (white matter reductions does just naturally decline with aging, part of normative aging)

Question 14

Explain the white matter structural brain changes with age.

Answer 14

• Most changes are often observed in areas involved with complex functions
  → frontal white matter tracts which connect the frontal lobe to other brain regions especially show degeneration, which can impact cognitive and motor functions due to disrupted communication between brain regions
• WM reductions are quite variable within and between people
  → the extent and rate of WM changes vary significantly
  → not everyone experiences the same degree of white matter loss, some people may have minimal or no WM loss
  → BUT, when losses are extreme, that’s when there’s a significant decline
• These losses are linked to widespread cognitive deficits
  → cognitive impact of WM with aging is actually quite broad, however, WM is mainly involved with processing speed, which is a major area that is affected because the role of WM is to facilitate communication between regions (frontal cortex relies heavily on white matter tracts)
  → declines here can lead to difficulties with goal setting, organizing thoughts, adapting to changing situations, the ability to make well-considered decisions and control impulses may also be affected
  → older adults may thus experience delay in responding to tasks

Question 15

Explain the grey matter structural brain changes with age.

Answer 15

• Reductions in grey matter volume are attributed to reduced synaptic densities (connections between neurons)
• GM reductions do not occur at the same rate between young and older adults in different areas
  → so a reduction in these means reduction in the amount of cell bodies throughout the brain
  → there’s a steady decline from 200 to 100 in synaptic density
  → its expected that if we live to 130, we would reach the same density as people with alzheimer’s disease
• GM reductions do not occur in everyone (or at the same rate in everyone)
  → reductions in brain volume is observed in some areas, more than others including the prefrontal cortex and the medial temporal lobe structures
  → reductions also differ between people
  → some will have an accelerated loss in GM, and some will have limited loss
• GM volume loss is associated with cognitive deficits – but the cognitive deficit is specific to the area of loss
  → p.ex: we can do paper tasks that look at executive functioning and if people score very very low, if we do an MRI, we’ll be able to see a reduction in GM in the frontal lobe

Question 16

What is a super-ager?

Answer 16

“super-agers” are older adults who don’t have much changes as they age; thus, they don’t lose a lot of GM or WM that we would see in the normal aging process

Question 17

What occurs to the grey matter in the lateral prefrontal cortex with age?

Answer 17

There is a general decrease here across age, BUT it is a wide range, i.e., some older adults have significant decline, while others have are above the mean of decline

Question 18

What occurs to the grey matter in the primary visual cortex with age?

Answer 18

The decline is not as bad here as it is in the lateral prefrontal cortex, so there is no real reduction in the visual cortex; i.e., no change in visual processing as we age.

Question 19

What occurs to the grey matter in the hippocampus as we age?

Answer 19

As we get older, the hippocampus experiences the most decline in aging, and it’s very steady after the age of 30

Question 20

Older adults typically show a __% volume loss in the whole brain and hemisphere.

Answer 20

15%

Question 21

Older adults show a 22% volume loss in the ___ lobes.

Answer 21

Frontal

Question 22

What hemisphere shows more decreased volume with age?

Answer 22

• The left hemisphere is more decreased in volume than the right
  → older men will typically show greater decreases in volume in left hemisphere and frontal left hemisphere than older women, indicating the larger left hemisphere is largely contributed to selective atrophy of the left frontal lobe in older men

Question 23

The peak rate of growth for grey matter occurs at ___; while the peak of grey matter volume occurs at ___.

Answer 23

6 months; 6 years old.

Question 24

Ventricle volume steadily increases after __ years of age.

Answer 24

40;
→ Coincides with maximum loss of gray and white matter starting around 40
→ Total cerebrum volume peaked just before the onset of puberty

Question 25

What are vascular lesions?

Answer 25

• Refers to abnormal changes or damages to blood vessels in the body, including those in the brain, which can disrupt blood flow; in the brain, if they’re in vascular regions they can lead to problems like stroke, hemorrhages and reduced blood supply

Question 26

What are the risk factors of the appearance of vascular lesions (i.e., due to risk factors such as…)?

Answer 26

• Appearance of vascular lesions due to risk factors such as smoking, high blood pressure, & drinking alcohol (because they appear in the vascular system
  → as we get older (60+) if they still have these vascular risk factors, the chances of having lesions is very high leading to decline, which can lead to dementia

Question 27

How are vascular lesions associated with dementia? With alzheimers disease?

Answer 27

Dementia:
- Brain damage from lesions due to impaired blood flow to the brain (causing dementia)
- With vascular dementia, we see that these lesions are all over the brain
Alzheimers:
- in alzheimers disease, they tend to be most prominent in the posterior regions

Question 28

Elaborate on white matter lesions.

Answer 28

• often indicate cortical vascular disease
• atrophy (decline in brain regions, both generalized or specific) is at least strongly associated with dementia
• these are areas of demyelinated cells found in the brain

Question 29

Elaborate on large cortical infractions (lesions).

Answer 29

• Cerebral infarction, area of necrotic tissue death resulting from blockage or narrowing in the arteries supplying blood and oxygen to the brain

Question 30

Elaborate on microbleeds (lesions).

Answer 30

• Small chronic brain hemorrhages
• Likely caused by structural abnormalities of the small vessels of the brain
• Structural abnormality of the small vessel

Question 31

Elaborate on multiple lacunar infarcts (lesions).

Answer 31

• Grey spots; most common type of stroke or blockages within the brain
• Result of these infarcts leading to blockages is that the small penetrating arteries that provide blood to the brain’s structures are impacted
• Stopping the regulation of blood flow within the brain; impacting specific parts of the brain getting oxygen

Question 32

What are the changes in protein composition that influence brain health and function?

Answer 32

• Many changes in proteins and enzymes change influence brain health and function
• Changes in protein and enzymes are not always structural changes
• Common increases in amyloid-beta and tau proteins occur with age (moderate amounts)
  → the increases seen with age are common, however a certain level of increase is seen in people with alzheimers
• May have specific directionality of accumulation in the brain (starting in temporal lobe and then spreading out)
• Can lead to dementia and cause severe deficits in cognitive functioning

Question 33

What are some functional connectivity changes?

Answer 33

• Dependent on white matter changes
• Reductions of tract are within lobe
• Reductions between lobe
• Reductions between hemisphere
• On the right side of the image (notes), the white lights are dimmer, which means lower functional connectivity due to white matter
• If we have damage to the tracts (because of dimmer white matter) these reductions impair the ability of these regions to exchange information effectively
  → p.ex: connection of left to right brain hemisphere won’t be as effective
• The reduction of WM tracts also slows down the transmission of neural signals along the affected tracts; so the slower signal transmission can lead to delays in processing and in responding to stimuli (leading to slower reaction times and impaired coordination)

Question 34

Slower signal transmission leading to delays in ___.

Answer 34

Processing

Question 35

What are the changes in neural activity (functional change) with age?

Answer 35

• Results in changes in brain activation patterns during cognitive tasks and at rest (seen in EEG)
  → we see a lot of changes in neural activity with age
• Changes observed can be decreases or increases in activity (some areas may see no changes)
  → as we age, parts of the brain that weren’t as active in the past can go up in neuronal activity (there’s a tendency of this)
  → decreases: if they have a reduction during cognitive tasks
  → increase might be observed in other regions to then compensate for that decrease
  → sensory areas may remain stable because there are no major changes in processing the sensory information to THAT level (sensory areas aren’t as steep of a decline)

Question 36

True or false: Neural changes are influenced by individual variability.

Answer 36

True: factors such as genetics, lifestyle, cognitive reserve and overall health

Question 37

How are the changes in neural activity as we age associated with cognitive deficits (or maintenance of cognitive functioning if the activity is compensation)?

Answer 37

• A decrease in activity is likely associated with decline in cognitive functioning, on the other hand if someone is showing compensation then maybe the increase in activity is helping their performance (other sections picking up slack)

Question 38

What did an EEG study show when comparing YA and OA doing easy, moderate and difficult tasks?

Answer 38

• Increases in OA in easy task but decreases in difficult task
  → Compensation
• YA’s neural activity doesn’t change across the tasks
• This shows OA need more resources to complete the task with the same efficiency as YA at easier levels, but as the task gets harder, they run out of resources and the activity decreases
• OA have reductions in activity in parietal and central region during 2-back
  → reflects a posterior-to-anterior shift; additional frontal regions in OA are often recruited to compensate for declines in parietal regions
  → OA will get both hemispheres to complete a task, while YA only need 1

Question 39

What are some alterations in blood flow seen with age?

Answer 39

• Alterations, as well as reductions in cerebral blood flow, are observed during cognitive tasks and at rest
• Similar to neural activity, there can be increases (compensation) or decreases in blood flow at rest or to cognitive tasks
  → whereas when they were younger, they didn’t necessarily need an increase in blood flow for the task
• Aging often leads to increase stiffness of blood vessels, which can impair the ability of arteries to regulate blood flow effectively
  → can result in reduced cerebral blood flow, and increase risk of vascular related cognitive impairments
• A reduction in activity is often associated with poorer cognitive performance
• Changes in blood flow are largely influenced by arterial stiffness and vascular risk factors
  → if an older adult does a task and they have lower blood flow, this is often associated with reductions in cognitive performance; on the other hand if they have increase in activity compared to young, they may perform at the same level or even lower than YA in some cases

Question 40

What did a blood flow study show when comparing older and younger adults doing a cognitive task?

Answer 40

• Older adults showed decreases in activity compared to younger in the right prefrontal cortex (a) and the parahippocampal gyrus/ hippocampus (b)
• in the same study, using the same task, they also found that older adults showed increases in activity compared to younger in the left prefrontal cortex
  → OA have a more bilateral activation in the prefrontal cortex (i.e., recruiting multiple sources to complete the same task)
  → this is why OA have higher activity, because they’re recruiting multiple sources

Question 41

What commonalities exist across all brain changes?

Answer 41

• Changes are influenced by individual variability
  → this is why we see general trends, this is why there is a range of decline called normal aging
  → due to genetics, lifestyle factors, etc.
• Associations with cognition are dependent on the area affected
  → p.ex: if the hippocampus loses grey matter, memory will be affected
• Compensation methods can result in increased blood flow and neural activity despite changes in GM
  → if an older adult has reductions in brain volume, they may recruit additional areas to help maintain performance

Question 42

Cognitive tests help us see how…

Answer 42

how people perform on certain tests, because they will tell us how active a specific brain area is (p.ex: if declines in inductive reasoning, there is decline in prefrontal cortex)

Question 43

How do we evaluate cognitive changes with cross-sectional data? (looking at a graph about cognitive changes)

Answer 43

• Studying different groups at the same time
• Declines are evident in all domains except verbal and numeric ability
• Inductive reasoning: typically involved in drawing general conclusions from observations
  → prefrontal cortex is involved in this reasoning
• There are overlapping areas
  → when using cognitive tests, we can’t exactly say that one specific brain area is the only one being utilized because a lot of them overlap in functions
  → in order to be thorough, researchers will have people do cognitive tests while in an MRI
• Provides a snapshot of the data
• This graph shows that there is age-related declines for speed, episodic memory, spatial ability and reasoning; only verbal and numeric ability remain somewhat stable

Question 44

How do we evaluate cognitive changes with longitudinal data? (looking at a graph about cognitive change, what declines are seen in longitudinal reserach)

Answer 44

-Declines are evident in all domains after 55 (inductive reasoning, spatial orientation, perceptual speed, numeric ability, verbal ability, and verbal memory)
- Only processing speed declines before 55 (starts after 25)
→ this means, reaction time is one of the first things to go with aging
- Inductive reasoning and spatial orientation are the last to decline
→ this means, executive decision making (p.ex: cost-benefit analysis) remains intact until a later age

Question 45

How do cohort effects play into cognitive changes studies?

Answer 45

• Different cohorts have different levels of cognitive performance
• The cross-sectional results may be influenced by cohort effects
• The same tests are being done, but different people are performing differently across time
  → p.ex: testing parents vs. students
  → due to access to education, their own lifestyle growing up, etc.
• Numeric ability declines: this is due to computer aid to help handle numbers
• A lot of aging research involves cohorts, to see if the declines we’re seeing are due to age or just due to the era in which each cohort was raised

Question 46

Differentiate crystallized from fluid intelligence.

Answer 46

• it’s important to know these and to control for them when doing studies
• Crystallized abilities: cumulative abilities built up over time (facts and skills)
  → E.g., general knowledge, vocabulary
  → Remains stable with age
• Fluid abilities: require flexibility of cognitive processing at time of test
  → E.g., processing speed, attention, task switching, ability to reason, think
  → Declines with age

Question 47

Explain what processing speed is in relation to crystallized vs. fluid intelligence.

Answer 47

• Processing speed declines steeply from early in life and is fluid
  → p.ex: when driving, your executive thinking is functioning, but processing time and reactions will be slower
  → you’re able to process everything just as well, but simply slower
  → reaction time is the biggest decline

Question 48

Explain what attention is in relation to crystallized vs. fluid intelligence and the different types of attention (3)

Answer 48

• Attention is fluid
• Not all aspects of attention decline
• Sustained attention: ability to focus on an activity over a long period of time; makes it possible to concentrate on an activity from start to finish, even with distracting stimuli
  → this one is preserved because older adults can read a book for a long period of time p.ex
• Selective attention: focusing to a particular object or stimulus for a certain period of time; when focusing on smt very minute, you’re able to inhibit unimportant details
  → this one declines
• Divided attention: such as driving, where you’re paying attention to other cars, your speed, the pedestrians, the signs around, etc.
  → this one declines

Question 49

What aspects of attention declines in aging?

Answer 49

Simple tasks do NOT decline
- sustained attention
Complex tasks DO decline
- selective attention
- divided attention

Question 50

What are the types of memory?

Answer 50

• Long term episodic memory
• Long term semantic memory
• Working memory
• Short term memory

Question 51

What is long term episodic memory?

Answer 51

• Memory with the conscious recollection of information from a specific event or point of time
  → retrieval of specific episodic memory
  → p.ex: seeing your pet for the first time, then a few years later seeing a similar dog, your brain will recall the memory of getting the dog for the first time
• Researchers can test this with a list of words, ask them to memorize it and repeat the list of words, THEN ask them to repeat the list again but with cue words
  → this is a very intuitive way to recall elements from long-term memory
• Stable until about 55-60
• Declines around 65

Question 52

What is long-term semantic memory?

Answer 52

• Meaning of words and concepts not specific to events or times
  → language comprehension, how we structure knowledge using words
• People can draw on memories from the past just by experience or word meaning associations
• p.ex of changes of semantic memory with age: learned a language at a young age, but stopped using it, you may have trouble recalling it
  → you can help recall it if you know the english word for example, it may play as a cue for the word in the other language
• p.ex: not remembering the name of movie but being able to tell someone what happens IN the movie, they could then help remember it
• p.ex: tip of the tongue or feeling of knowing smt, trying to retrieve the name of smt that you should know can come to you if you can just tap into associated words
• Increases from 35-55 followed by a plateau

Question 53

True or false: Long-term semantic memory is relatively spared in the normal aging process.

Answer 53

True: We don’t lose it as much

Question 54

What is working memory?

Answer 54

• Holding information in mind and manipulating it in short periods (typically a few seconds, less than a minute while performing mental operations)
• includes temporary holding, storing and processing information for complex tasks such as learning, problem solving and decision making
• with working memory, we’re encoding, storing and retrieving
• p.ex: complex math question will be worked out here
• p.ex: smt important being said in class, you’re taking the important parts of it, holding it in this working memory and writing it down

Question 55

What happens to working memory with age?

Answer 55

• Declines in aging
• the loss of ability in holding items
• however, these declines are not universal, it can depend on the type of information presented AND can vary across tasks
  → there is a general trend of decline in working memory, but it isn’t always the case for EVERY task
• typically we see a decline in spatial working memory and it’s even greater than verbal working memory
• BUT if an older adult has always been really good with numbers, this greater prior knowledge can counterbalance declines in working memory in some situations (p.ex)
• the general consensus though, is that the more complex the task, the more decline we see in OA compared to YA

Question 56

What is short-term memory?

Answer 56

• Holding information in mind for short times
• Relatively preserved in normal aging
• p.ex: complex math question will be stored here

Question 57

Long-term memory is a second order memory component; explain this statement.

Answer 57

i.e., whatever you have stored from short-term memory (hence also working memory) will be passed onto long term if it’s important or if there’s an emotional component to it→ p.ex: seeing your pet for the first time

Question 58

Explain what language is in relation to crystallized vs. fluid intelligence.

Answer 58

• Composed of both crystallized and fluid cognitive abilities
  → because of this combo, we see declines in some aspects but not all when it comes to language; thus the overall language ability remains in tact with aging
• Vocabulary remains stable and even improves over time
• Semantic memory also remains stable or improves
• Visual confrontation naming is stable until around age 70, and then declines
  → visual confrontation naming: the person recalls the names of visually presented items
• Verbal fluency also shows declines with aging
  → if we were to show an older adult a picture of a projector, they might be able to know what that is (visual confrontation naming), BUT if we presented them with the word for it (rather than the picture) they may not remember it

Question 59

Talking about processing speed, attention, memory and language; which of them are crystallized vs. fluid, and which ones decline in aging?

Answer 59

Processing speed: Fluid - Declines in aging
Attention: Fluid - Simple tasks, no; complex tasks, yes
Memory: Fluid - Mixed
Language: Crystallized > Fluid - In general does not decline, but with verbal confrontation naming and naming fluency, yes

Question 60

What are the ways we can maintain high functioning with age? (4)

Answer 60

1) Physical activity
2) Intellectual stimulation
3) Minimize chronic stressors
4) A brain-healthy diet

Question 61

How does physical activity help maintain high functioning?

Answer 61

• Exercise aids executive function
  → p.ex: regular aerobic exercise (walking, swimming, biking) have been linked to reduced decline in gray matter volume in brain regions associated with exec functioning (prefrontal cortex and hippocampus, both of which typically shrink with age)
  → p.ex: yoga and tai chi have been shown to improve emotional regulation and exec functioning
• Reduces declines in tissue density in frontal, parietal, and temporal cortex
  → significant positive effect on executive functioning (planning, decision making, working memory); these improvements in exec functioning are particularly important if you want to maintain independence and improve your quality of life
• Might have global effects on the brain

Question 62

How does intellectual stimulation help maintain high functioning?

Answer 62

• Mental activity seems to protect against age-related declines and progression to AD
• Mental activity also increases our baseline cognitive function
  → p.ex: reading books (not just fantasy), playing chess, learning new languages
  → older adults who engage in these activities experience lower rates of cognitive decline
• Rats show neurogenesis in enriched environments, indicating possible benefits for cognitive stimulation

Question 63

How does minimizing chronic stressors help maintain high functioning?

Answer 63

• Increased stress is associated with risk of alzheimers and faster rate of cognitive decline
• Also damages hippocampal neurons
  → increased stress increases glucocortisol levels, which accompanies stress and might damage neurons, especially over the lifespan
• Cortisol administration reduces glucose metabolism in the hippocampus in normal older adults
  → prolonged exposure to stress increases cortisol, memory

Question 64

How does a brain-healthy diet help maintain high functioning?

Answer 64

• Focusing on minimally processed foods, more on foods that promote a better balanced diet
• A diet rich in:
  → Poly- and mono-unsaturated fatty acids (found in fish and olive oil)
  → Polyphenols & Antioxidants (found in citrus and dark-skinned fruits and veggies)
  → *naturally occurring compounds that we can find in many natural foods are very good for the brain and diet
• Can slow cognitive decline and even prevent progression to AD

Question 65

There are 14 main ___ risk factors that increase risk of cognitive decline in age. __% of risk factors are ___.

Answer 65

Modifiable; 45%; modifiable

Question 66

What is cognitive reserve?

Answer 66

• Better cognitive reserve is protective against age-related changed
• Individual differences in how people process tasks, which allow some people to cope better than others with brain pathology
  → extra bit of cognitive processes that we have
  → ability to adapt; how efficient we are, what our cognitive capacity is to do certain tasks
  → explains how people with the same brain morphology can have differences in day-to-day functioning and now people can develop dementia while others don’t (even if they have the same brain as someone without)
  → that’s why we can’t always assume someone’s cognitive functioning based on ONLY an MRI

Question 67

What are the positive and negative factors that improve healthy cognitive reserve?

Answer 67

• Positive: Mental stimulation, active lifestyle, social simulation, cognitive remediation, physical activity
• Negative: Poor education, mood disturbances, poor nutrition, alcohol/drug abuse, poor health

Question 68

How do the processes of cognitive reserve interact to either build it or lower it?

Answer 68

• They are always interacting
• Individual differences in interactions of innate genetic and lifetime experiences such as education, occupation, exercise, social engagement (factors to the left) can either lead to a high cognitive reserve, or can lead to a low cognitive reserve, if all of these interact in a negative way
  → build-up of all these interacting factors that allow you to cope better with brain changes

Question 69

True or false: Cognitive reserve is static and unchangeable.

Answer 69

False; cognitive reserve is not static, not fixed or unchangeable, it’s smt that is always changing (p.ex: when you get older and start reading more, you’re building your reserve)
→ its always being influenced by interactions of genetic and lifetime experiences (education, stimulation, etc.)

Question 70

Cognitive reserve acts as a ___ between pathology and clinical outcome. Explain this.

Answer 70

→ reserve is a third variable that affects the relationship between both variables
→ cognition as IV, and brain as DV, the moderator (CR)

Question 71

How does cognitive reserve influence how a person copes with pathology?

Answer 71

• The brain actively attempts to cope with pathology by using pre-existing cognitive-processing
  → CR moderates, therefore an individual with high CR will cope better with the same amount of pathology (dementia) that’s seen in an individual with low CR
  → p.ex: if someone with high CR has dementia, it would take them longer to succumb to the symptoms that come with dementia
  → p.ex: brain as a computer; the more files you have in the computer, the more intricate those files are, the longer it takes for a virus to break down all those files

Question 72

True or false: better cognitive reserve can protect you against age-related changes.

Answer 72

True

Question 73

How is dementia different in a person with high cognitive reserve, vs. someone with low cognitive reserve?

Answer 73

• Someone with high reserve requires more pathology to show the same symptoms
  → the disease will emerge later in people with high CR
  → this creates a steeper decline in those with high reserve; it takes a lot more amyloid buildup in the brain for them to first start showing decline, but when they do, their decline is quite rapid
• Someone with high reserve will show less symptoms than someone with low severity
  → people with high CR remain clinically normal for longer periods of time even though they have the same amyloid buildup as those with low CR
  → even with lower amounts of amyloid buildup, they already start off with mild AD
  → those with high CR will appear to be less clinically severe than those with lower CR

Question 74

What type of life experience is associated with better cognitive function / high cognitive reserve?

Answer 74

At any given level of brain pathology, higher education was associated with better cognitive functioning

Question 75

True or false: CR is related to brain size.

Answer 75

False

Question 76

What is brain reserve?

Answer 76

• Individual differences in the brain itself allow some people to cope better than others with brain pathology
• Often measured in terms of neurobiological capital (numbers of neurons, synapses, etc.)
• Can be considered a more passive form of reserve (cause it’s fixed)… it does not invoke active adaptation of functional or cognitive processes in the presence of insult
  → the brain reserve is a fixed construct, unlike cognitive reserve
• Cognitive deficits or functional deficits would only occur after a certain fixed threshold has been reached
  → for those with greater BR, there’s essentially more to lose if they’re on the dementia trajectory before cognitive changes occur; because it does not invoke active adaptation
• A larger brain might be able to tolerate more pathology or more amyloid buildup before it reaches the clinical threshold and symptoms begin to appear BUT, it’s still fixed with a fixed amount of resources

Question 77

Differentiate cognitive reserve from brain reserve.

Answer 77

Cognitive reserve
- Individual differences that influence how the brain copes with pathology
- Measured in terms of educational attainment, social engagement, occupational status
- Active, dynamic process
- Not fixed or unchangeable
Brain reserve
- Individual differences in the brain itself that help people cope with pathology
- Measured in terms of biological processes such as number of neurons or synapses
- Passive and static
- Is a fixed construct

Question 78

Explain the scaffolding theory of aging and cognition - revised.

Answer 78

• Life course model that captures how lifestyle and brain factors interact to influence aging and cognition
  1) Cognitive reserve factors such as education and multilingualism
  2) Brain reserve factors such as head trauma
  these first 2 both influence brain structure and function
  3) Eventually everyone declines, therefore compensation methods may be used to help maintain functioning
• brain changes occur naturally, because we all experience cognitive decline, btu the brain may try to compensate with these changes using a variety of methods; this is where compensatory scaffolding comes in
• this (STAC) is the brain responding to changes in aging and dementia by engaging in continuous functional reorganization and repair to maintain high cognitive function
• how?
  → the brain recruits additional brain regions in order to cope with the pathology in a particular brain region

Question 79

What is the posterior to anterior shift in aging?

Answer 79

• Part of the scaffolding theory of aging and cognition
• It’s how the brain responds to changes in aging and dementia; by recruiting additional brain regions in order to cope with the pathology in a particular brain region
  → The main area involved in memory is the parietal region
  → Memory declines are associated with atrophy and pathology in parietal regions
  → Because of this decreased functioning, additional frontal regions are often recruited to help maintain high function and to compensate for these declines
  → This additional recruitment of the anterior regions is considered a method of compensatory scaffolding and reflects a posterior-to-anterior shift in aging

Question 80

What is bilateral recruitment in the STAC-r?

Answer 80

→ Left frontal Activity is increased in high-performing older adults vs younger adults
→ Low performing older adults do not show this additional recruitment
→ older adults show an additional right region recruitment (whereas YA show only a left region activation
→ the right lateralized engagement in OA was seen as them recruiting additional area during a verbal memory task, which allowed them to perform that task