Lecture 1: Introduction to cognitive aging Flashcards
When it comes to general aging, there is a decline in acuity of senses; what are the senses affected?
Vison
Audition
Somatosensory
Gustatory
Olfactory
Vestibular
What are the reasons why visual acuity declines?
changes in our visual system which occur with normal aging
there are also a number of disorders that increase this in prevalence with age
What is the sclera?
the white part of his eye
What is the cornea?
surface of the eyeball
What is an anterior chamber?
space between cornea and lens (filled with aqueous humour)
What is the iris?
changes to the pupil size
What are lens?
changes shape to focus light rays on retina
What is vitreous humor?
maintains shape of eyeball
What is within the retina?
Rods: night visions
Cones: day & colour vision
What are some examples of age-related changes in vision?
cornea becomes thicker and less curved
anterior chamber become smaller; aqueous humorous may drain inadequately, causing increased intraocular pressure and glaucoma
iris colour fades and pupil diameter decreases
the lens: continues to grow, becomes less elastic, denser, and yellower this causes changes in colour vision (likelihood of presbyopia increases
vitreous humour becomes more liquid. loose cells may cause shadows; retina: vessels & capillaries narrow, loss & change in chemical sensitivity of rods & cones
What is Arcus senilis?
gray ring that forms around the edge of the cornea.
Arcus senilis is caused by fat lipid deposits deep in the edge of the cornea. It does not
affect vision, nor does it require treatment
What do age related changes mean for decreased visual acuity?
changes in refraction by cornea & lens
* decreased accommodation ability
* less light admitted due to smaller pupils
* reduced number of rods & cones
* Decreased light/dark adaptation.
* Higher visual threshold (minimum light required
to stimulate receptors).
What is aging?
begins from birth
What is senescence?
the final stage(s) of the normal lifespan
What are the ages within older adulthood?
young old (65-74)
old-old (75-84)
oldest old (over 85)
What are the three ways we define “old age”
Chronological, biological and psychological
What are the 5 subfields of cognition?
Memory, executive function, language, numerical cognition and categorization & knowledge representation
What are the three ways we can study cognition?
Standardized test, on-line studies (chronometric) and neuroimaging
What is a standardized test and name example?
how we assess cognitive function: MMSE
What is MMSE?
Mini Mental State Examination; a screen for dementia in multiple cognitive domains
What are on-line studies and name examples?
use to measure the time to react to stimulus as well as response accuracy in tasks requiring cognitive processing: digit span, troop test, Boston naming test
What is a digit span?
when you repeat numbers; forward test is for short term memory and backward test is for working memory
What is a stroop test?
assessing inhibitory function
what is a Boston naming test?
test of language function
What is neuroimaging and provide example
medical images of the brain: fMRI & PET
What is fMRI?
Functional Magnetic Resonance Imaging measures the hemodynamic response in the brain; the underlying assumption that oxygenated blood goes to areas where neural activity is occurring
What is a PET?
Positron Emission Tomography detects the gamma rays emitted when the positron emitted from the radioactive substance collides with an electron in the tissue
What are three research methods?
Human research, animal research, in vitro research
Name advantages of human research
since the topic of interest is humans and we are using humans its the best
we can study systems that are difficult to study in animals/in vitro models
don’t need to worry about if findings will transfer to a human model
List disadvantages of human research
the aging is very heterogenous across individuals; people can be the same age but look completely different, act completely
the gang is ver heterogeneous within individuals; some systems in the body age faster than others like your hearts in good shape but not your bones
What are challenges in human research?
it is difficult to follow an individual from brith to death due to cost and attrition of subjects due to unwillingness to participate, illness, or death
there are ethical considerations that are grater with humans than in vitro or animal research such as experimental approaches that are unethical for humans but good In other cases
some approaches also need to be tested first in animals/in vitro before humans (gene therapy)
Why do we use animals for studies?
the aging process is much faster and we can build models and perform studies we can’t do in humans
How do we choose a species and what are some examples we can choose from?
have to factor in your research question, select species that have a particular feature of interest, often in an exaggerated form; genetics in mice, opossum for fast aging rate, canine models for AD
What are some considerations in animal research?
specificity: the model must exhibit trait of interest, generalizability/transferability: the results observed in the chosen model must be applicable to other species, feasibility: the availability, cost, convenience of the model must be reasonable
Why do we use in vitro cells/tissue?
can examine cell properties at different ages
cultured cells can serve as model for identifying specific cell functions or mimicking aging pathologies
Why use birds, bats and naked mole rats?
live longer than humans in terms of the amount of oxygen processed
ties into major theory of aging, free radical theory
great species for assessing interventions based on free radical theory
What is the hayflick limit?
hay flick observed that cells dividing in cell culture divided about 50 times before dying; the number of times our cells can divide before experiencing the senescence phase; as cells approach the limit they show more signs of old age
What are the advantages and disadvantages of in vitro?
easy to control confounding variables
however, we don’t know how well the results in vivo; just because in works in cells doesn’t mean it will work the same in animals/humans
