Quiz 1 Flashcards
aging is universal
- one of our major goals is to get old
- all of us are aging
Gerontological explosion
older adults are living longer, the population is growing
they have more active lifestyles and more are in the workforce
pockets of preservation
performance is preserved over age for World Knowledge
hidden upsides of aging
what older adults are better at than young adults
successful aging
varies across individuals, time, and situations
- meaningful, joyful, healthy
selective optimization and compensation
- change what we do to fit our abilities
- select activities and goals we wish to achieve, optimize the time and abilities we have to achieve these goals, and compensate for any declines or deficiencies that may result from aging
- a trick to successful aging
socioemotional selectivity theory
- our goals shift as we age from a focus on accumulating knowledge to emotionally meaningful goals
- driven by a limited perspective
value-directed remembering
as we age, we get more selective about what we value and prioritize that
subjective age
- what age you feel like
- a positive attitude, associated with health, cognition, strength, and longevity
brain reserve hypothesis
brain reserve may function as a moderator on the relationship between brain damage and cognitive outcome
ways to boost cognitive reserve
- genetic influences
- socio-economic status
- intelligence
- educational attainment
- social engagement
- sleep
- cognitive stimulation
- healthy lifestyle
nun study
- the nuns had biological signs of aging (atrophy, plaques and tangles) but showed normal cognition
- cognitive reserve was a protective factor, active lifestyle prevented cognitive decline
cognitive training (pros and cons)
Pros: boosts cognition
Cons: does not generalize to other activities or daily life; no more beneficial than “real-world” cognitive activities
Pros and cons of animal research in aging
Pros: great for studying neural mechanisms, reduces variables and confounds
Cons: ethical concerns, still expensive, human aging has unique attributes, cognitive functions are difficult to measure in animals
pros and cons of behavioral research
Pros: cheap and easy, non invasive, can answer most questions about cognition
Cons: can only infer effects of neural structure and function
longitudinal study design (pros and cons)
Pros: control for individual differences and cohort effects
Cons: takes 50+ years to run an aging study, retest effects, attrition
cross-sectional study design (pros and cons)
Pros: faster to run, no attrition, no practice effects
Cons: individual differences, cohort effects
cohort effects
generational differences; differences that occur due to one’s membership in a group
attrition
people leaving a study
practice effects
changes in score due to having taken the test before
cross sectional does not equal longitudinal: implications for research
cohort effects can be mistaken for aging effects and vice versa
cohort-sequential studies
design that combines cross-sectional and longitudinal elements by following two or more age groups over time
Twice-minus-once-tested method and
Quasi-longitudinal method
Trying to predict what follow up scores would be without practice effects
Correlation does not equal causation (why this is a particular problem for aging research and how to get around it)
- it is impossible to manipulate age so the research is always correlational
- we can conduct studies that turn young adults into old adults by manipulating resources; ensure there are no plausible alternative explanations for the relationship; be careful with wording
selection bias
-self selection: contacted by adults who live independently, active in community and see ads, interested in psychology research, concerned about their cognitive declines, healthy and able to travel
- our selection: exclude poor cognitive performers, recent cardiovascular events or head trauma, are non-native English speakers
identification as “older adult”
where does old age begin? No distinct line
age as a continuous variable (linear vs non linear effects of age)
do dependent variables have inflection points or change linearly over time
Pros and cons of structural neuroimaging studies
Pros: directly measure neural structure, can be used to examine brain-behavior connections, relatively non invasive
Cons: very expensive (time and $), lots of contraindications for fMRI means more selective sample, correlational
gray matter
neuronal cell bodies
white matter
connections between brain regions
Structural magnetic resonance imaging - how does it work
aligns water molecules in brain and sends pulses to disrupt this alignment; measures the different speeds or rebounding
Structural magnetic resonance imaging - what is measured
gray matter
Diffusion tensor imaging - how does it work
measures the diffusion of water
Diffusion tensor imaging- what is measured
strength of white matter integrity
strong= ellipsoid patterns
poor= spherical patterns
axon
long, thin fiber that carries electrical pulses from the cell body
myelin sheath
fatty layer that insulates the axon and increases the speed of electrical impulses
frontal lobe
controls higher order functions, behavior, emotions, language
parietal lobe
processes sensory information
occipital lobe
processes visual information
temporal lobe
processes sensory information, hearing language and memory
hippocampus
learning and memory
amygdala
assigns emotional salience
thickness
traditional cortical measure for measuring gray matter
are
another traditional cortical measure for measuring gray matter
volume
traditional cortical measure for measuring gray matter; most common
fractal dimensionality
measure of cortical folding
how much is lost by increasing the size of the voxel (3D pixel)
More complex objects lose fidelity with larger voxels
cortical parcellation
dividing gray matter locations in the brain into parcels
Fractional anisotropy
measure of integrity of myelin sheath along axons
age related structural changes - gray matter
longitudinal decrease in gray matter
age related structural changes - white matter
longitudinal decrease in white matter
age related structural changes - CSF
longitudinal increase in cerebrospinal fluid (ventricles and sulci)
age related structural changes - regional differences
- gray matter decrease is greater for frontal and temporal lobes, less for parietal and occipital lobes
Why look at structural changes
- estimating effects of age
- distinguish healthy from pathological aging
Motivation as a mediator (socioemotional selectivity theory)
As a driver of age related change
- as we age, we prioritize affective and emotional goals to promote wellbeing
Speed of processing theory
As a driver of age related change
- we get slower as we age, this slowing affects cognitive performance
Independent variable
the variable that is manipulated
dependent variable
the variable that changes as a result of manipulation of the independent variable
mediating variable
a third variable that explains the relationship between an independent and dependent variable
Requirements for mediation
1) significant effect of independent on dependent variable
2) significant effect of independent on mediating variable
3) significant effect of mediating on dependent variable
4) Effects of independent variable on dependent variable disappears or is reduced when the mediating variable is added to the model
Interpreting mediation
if it does not make sense, the statistics do not matter
Brain aging hypothesis
the reduced structural integrity in older age interferes with cognitive performance
Why difficult to test neural mediation
high-dimensionality and complex interrelationships
MoCA
Montreal Cognitive Assessment - test for mild cognitive impairment
Rangus et al. results: effects of age on MoCA subscales
direct age-related effects on memory, attention, and visuospatial processing
Rangus et al. results: greatest age-related structural changes
greatest age-related reduction in medial temporal lobe volume
Rangus et al. results: greatest mediating effects on total MoCA score
greatest total mediating effects in frontal lobe
Double mediation of white matter integrity and processing speed
increased age is associated with reduced processing speed, caused by
reduced white matter integrity, resulting in impaired cognitive performance
Why study mediation?
- understand causes of age-related impairments
- identify targets for intervention
- design better experiments
Senile Dementia of the Alzheimer’s type
Most common form of dementia
Prevalence of AD
15% of general population over 65
5.1 million Americans, 26.6 million worldwide
Alois Alzheimer
German psychiatrist, first described the disease
Auguste D
patient studied by Alzheimer
profound memory impairment, language disruptions, delusions, loss of self
AD pathology
- atrophy - degeneration of temporal lobe and parietal lobe, parts of frontal cortex and cingulate gyrus
- Tau tangles - deposits of protein tau that accumulate in nerve cells
- amyloid plaques - deposits of beta-amyloid protein that accumulate in the spaces between nerve cells
Development of AD - stages
AD is progressive
Preclinical, MCI, dementia
Development of AD - symptoms
Preclinical - slight changes the individual might be aware of
Development of AD -regional pathology
- early pathological changes are seen in the medial temporal regions
- pathological abnormalities impact more and more brain regions
- some regions show minimal pathology in more advanced stages, like primary motor and sensory cortex
Development of AD - cognition
MCI: episodic memory impairment
Early AD: memory (particularly episodic, newer memories lost first), select aspects of executive function
Moderate AD: difficultly with navigation, spatial layout, directions; naming and verbal fluency impairment
Attention is largely unaffected
Treatment options
- cholinesterase inhibitors: for mild/moderate AD, postpones the worsening of symptoms for 6-12 months in half patients
- Namenda: moderate/severe AD, may delay the worsening of symptoms in some, allows patients to maintain certain daily functions
Anti-amyloid antibody infusions
- facilitate the removal of beta-amyloids in the brain, based on amyloid hypothesis
- successful reduction in amyloids, inconsistent effects on cognition, concerning side-effects
Gamma neuromodulation - why might it work?
cognition is supported by synchronous oscillations in different parts of the brain, particularly gamma waves
-gamma is decreased in AD, tau and amyloid levels correlate with gamma
gamma modulation is shown to decrease AD symptoms
-reduce tau and amygdala pathology
-physical neural changes at the synaptic level
-decreased cognitive decline
