Creierul uman de-a lungul aniilor - imbatranirea

Question 1

what is white matter

Answer 1

structures that hold the grey matter

white matter - axons
-myelinated axons that told to different parts of the brain

not all axons are myelinated- the ones that need to be efficient are. If you lose myelination that becomes a problem to coordinate your body

it’s more active in some parts than others

Question 2

what is blood flow

Answer 2

brain is bathed in blood
thats where it gets energy from

3 major arteries coming into the brain - anterior, middle posterior cerebral artery

as you go deeper into the brain, arteries become finer
damage seen in ageing is to do with those fine blood vessels no longer functioning well and sending signals

blood carries oxygen to parts of the area that are more active

Question 3

What are the 3 arteries that provide blood to the brain?

Answer 3

Anterior Cerebral Artery
Middle Cerebral Artery
Posterior Cerebral Artery

Question 4

Where does brain take oxygen and glucose from?

Answer 4

From the blood stream.

Question 5

What are the changes in brain with age?

Answer 5

White matter volume decreases
swollen ventricles
more folds
lesions in the brain

Question 6

what is atrophy

Answer 6

enlarging of ventricles and sulci is related to reduction in brain tissue both in grey and white matter

Question 7

What is white matter hyper-intensities

Answer 7

white matter lesions

amount of areas that have lesions increase
start as early as in your 60s and go up until old age

Question 8

white matter across lifespan

Answer 8

increase from 20s and 30s
steady across 40s and 50s
50 and 70 you have beginning of decline
sharp decline from 70 onwards

period of time in which white matter is increasing

Question 9

grey matter across the lifespan

Answer 9

stays steady throughout life
does not decrease in volume greatly

Question 10

cognitive changes in ages

Answer 10

working memory
LTM
STM
see a steady decline from 20 onwards

verbal knowledge
stays steady and increases somewhere - you keep adding into your vocabulary

Question 11

What are the two theories of cognitive ageing?

Answer 11

1. Common cause hypothesis
2. Specific gain/loss hypothesis

Question 12

What is the common cause hypothesis?

Answer 12

Deficits in a single ability can explain almost all age-related cognitive decline.
-magic key that explains all deficits
- the cascade effect
-ones this goes down, it affects everything else

So if you are bad in one ability it is said that that can impact all your other abilities.

Question 13

What is the specific gain/loss hypothesis?

Answer 13

Age-related cognitive decline is best explained by changes in neuroanatomical so structure or function.
-changes to actual physiology of the brain

So this theory says that decline in cognitive ability is due to physical changes in the brain

Question 14

example of common cause hypothesis

Answer 14

information processing speed

Question 15

example of specific gain loss

Answer 15

frontal-executive hypothesis

disconnection hypothesis

Question 16

2. what is frontal executive hypothesis

Answer 16

frontal lobes
executive function
personality
higher cognition

Grey matter in frontal lobes is negatively impacted by ageing
So complex processes are going to be impacted

Executive tasks worsen with age - you see decline in grey matter in frontal lobes

Question 17

2. What happens to the executive function as a result of age-related damage to frontal lobes?

Answer 17

Executive function is a primary cognitive deficit in ageing.

So frontal lobes are affected and that in turns affects EF because that’s where it is located in the brain.
This is the frontal executive hypothesis.

Question 18

What is the role of white matter?

Answer 18

White matter is connecting areas of brain matter across the brain.

Question 19

3. What is the disconnection hypothesis in ageing?

Answer 19

Age-related white matter damage disrupts communication between brain regions.

-ability of brain to talk to different parts is going to be affected

That means complex cognitive abilities that rely on integration of information between brain regions will be affected.

EF relies on communication to and from frontal lobes.
Therefore EF is affected.

Question 20

What do both frontal executive and disconnection hypothesis suggest?

Answer 20

That executive function is the primary deficit in ageing.

Question 21

what is support for frontal executive hypothesis

Answer 21

grey matter decline in ageing
cross-sectional MRI study
decline per decade in terms of grey matter
prefrontal cortex has highest decline that any part of the brain - 4.9%

in hippocampus there is a decline but only 2% - hippocampus only areas that has neurogenesis

superior parietal cortex - 4.3% decline

Question 22

what is support for disconnection hypothesis

Answer 22

white matter volume decreases
and white matter goes through damage as WMH increases

Cross sectional: Diffusion tensor imaging shows sharp decline in white matter integrity with age

Longitudinal: white matter also sensitive to change in 2 years

Question 23

What happens to executive function with age?

Answer 23

It declines with age.
EF declines can have a knock off effect on LTM. - but not the other way around. EF was the primary deficit in one study

Question 24

what is the problem with research on executive function

Answer 24

mixed results
not clear whether EF decline is greater than other cognitive types of decline

Question 25

What is the relationship between grey matter and executive function? in support of frontal executive hypothesis

Answer 25

Frontal grey matter volume is associated with EF in ageing
In older subjects, individuals with lower frontal grey matter, lower scores in EF tasks.

Association does not mean cause

Question 26

what is the evidence for frontal changes in ageing

Answer 26

young adults used lateralised parts of the brain

as you get older, you start recruiting other parts of the brain

you can adapt to make changes to cope

Question 27

what is support for disconnection hypothesis

Answer 27

Working memory declined significantly over 2 years

White matter integrity correlated with EF, working memory and information processing speed

Question 28

What are white matter hyperintensities?

Answer 28

Brain white matter lesions. Larger WMH have been associated with Alzheimer’s disease and cognitive decline.

Question 29

What happens to WMH with age?

Answer 29

It increases with age. So that suggests that there is damage to white matter with age.

Question 30

what are problems with executive function hypothesis

Answer 30

evidence for non-frontal grey matter decline - superior parietal loss

EF is not only concentrated in frontal love, its distributed in the brian

Question 31

What are problems with disconnection hypothesis

Answer 31

Not only EF associated with white matter decline
EF also affected by processing speed and episodic memory

Question 32

what is the competing hypothesis

Answer 32

they dont have to be mutually exclusive
frontal lobes are connected to the rest of the brain by white matter
if you have effects in white matter, you have effects in frontal lobes
white matter damage occurs across the whole brain and within the frontal lobes
grey matter and white matter are connected and influence each other

Question 33

What happens as a result of changes in the cardiovascular system?

Answer 33

Changes impact blood supply to the brain.
Interruption to blood supply is associated with WHM and risk of stroke.

Question 34

What is hypertension?

Answer 34

High blood pressure

Question 35

What’s the relationship between hypertension and WMH?

Answer 35

Hypertension increase risk of developing WMH.
Hypertension is also related to cognitive difficulties.