cognitive neuroscience of ageing

Question 1

at what age is the brain fully developed

Answer 1

early 20s

Question 2

at what age is volume loss seen in brain

Answer 2

from young adulthood

Question 3

main parts of nerve cell

Answer 3

dendrite
axon
soma

Question 4

process of action potential in a nerve cell

Answer 4

inside of cell at rest is neg, if stimulus is good strength it alters balance of ions reaching threshold so action potential travels to pre synaptic terminal

Question 5

what does action potential cause

Answer 5

release of neurotransmitters to synaptic cleft
exitatory or inhibitory (increase or supress)

Question 6

how is the brain divided

Answer 6

according to structural similarity of neighbouring cells called brodmann’s area

Question 7

what does it mean by saying brodmann’s area was given functional relevance

Answer 7

instead of BA4, primary motor cortex is said instead

Question 8

what is the gyri and sulci

Answer 8

gyri = peak
sulci = trough

Question 9

what are the tissue types in brain

Answer 9

white matter = connections
grey matter = destinations/activity
CSF (cerebral spinal fluid)

Question 10

what is the cerebellum

Answer 10

not a lobe
-movement and balance

Question 11

function of:
frontal lobe
temporal lobe
parietal lobe
occipital lobe

Answer 11

frontal = executive hub, decisions
temporal = memory
parietal = attention
occipital = vision

Question 12

what does cortical and subcortical mean in the brain

Answer 12

cortical = superficial
subcortical = deep

Question 13

anatomical terms:
anterior
posterior
superior
inferior
dorsal
ventral
rostral
caudal

Answer 13

anterior = front
posterior = behind
superior = above
inferior = below
dorsal = above, anterior posterior axis
ventral = below, anterior posterior axis
rostral = to front, frontal cortex
caudal = to back, occipital cortex or brain stem

Question 14

what are the methodologies looking at the neuroscience of ageing

Answer 14

PET = positron emission tomography
MRI = magnetic resonance imaging
FMRI = functional magnetic resonance imaging
DWI = diffusion weighted imaging

Question 15

how do PET, MRI, FMRI and DWI work

Answer 15

PET = shows area of high glucose activity in diff regions

MRI = mm precision and detail

FMRI = shows active regions in specific tasks by looking at metabolic demands (areas with most O2)

DWI = white matter tracks by observing H+ molecules, shows where things happen not when

Question 16

brain shrinkage and ventricular expansion in older adults

Answer 16

-brain shrinkage and ventricular expansion seen and replaced by CSF
-approx 3% expansion per year in older adults

Question 17

grey matter and white matter decline research

Answer 17

sullivan et al 2004
-grey matter decline is fairly linear until age 70/80 yrs
-white matter declines after about 45yrs

Question 18

what does it mean if white and grey matter decline

Answer 18

white matter decline: decline in myelin sheath, slower processing so higher RT

grey matter decline: loss of vol and scope for activation, less available resources to perform cog functions e.g difficulty processing high cog loads and more demand on WM

Question 19

what is dopamine

Answer 19

a neuromodulator that regulates neurochemicals like GABA

provides evidence for chemical change in older adults

Question 20

what are the key regions associated with dopamine

Answer 20

striatum (connections with limbic system and frontal regions explaining links with abnormal emotional disorders)

Question 21

dopamine in older age

Answer 21

reduced binding due to less dopamine from age 50

Question 22

decreased dopamine research

Answer 22

seeman 1987
- 2-3% decline per decade after age 20

Question 23

what issues does having less dopamine cause

Answer 23

-problems with brain network dynamics and failure to activate task specific regions and deactivate irrelevant ones

Question 24

what is an issue and solution for FMRIs

Answer 24

• looks at haemodynamics and cant do this so well with thickened blood vessels that are seen in older adults
  e.g tsvetanov 2015: thought they had detected change in brain activity but it was actually change in blood properties

solution: study neurons directly NOT properties of blood by using EEG, MEG etc

Question 25

what does GABA stand for what does GABA show GABA and old age

Answer 25

GABA = gamma aminobutyric acid (primary inhibitory neurotransmitter) -shows neurochemical changes that take place -Gao et al 2013: 5% decline per decade of life -inability to filter out irrelevant items: larger N100 for irrelevant stimuli meaning less able to filter out distractors -inability to select correct response: RT time delay, increase by 1.5ms per year -deficits in multisensory integration (Freiherr et al 2013) = not able to distinguish between diff sources e.g crossing busy road

Question 26

visual perception in older adults

Answer 26

-amount of light entering retina of 60yr old is 1/3 the amount of a 20yr old -means slower search rates through visual displays

Question 27

what are the 3 pathways for visual info

Answer 27

dorsal stream = where something is (occipital -- parietal -- frontal lobe) ventral stream = what object is (occipital -- temporal -- frontal)

Question 28

age and activity in visual regions and why increase in visual regions

Answer 28

decline in activation of visual cortical regions although increase in prefrontal activation perhaps increase in prefrontal regions as decline in visual processing means frontal cortex must work harder

Question 29

memory processes research in older adults

Answer 29

Morcom et al 2003 -pp: 21-68 yrs -FMRI to look at brain activation in line with word judgement task -recognition memory tested after 10 or 30 min delay -in older adults we see more bilateral frontal activity

Question 30

working memory and older adults what occurs during encoding and retrieval

Answer 30

-task complexity produces greater age differences -vulnerability of memory due to loss of distractor inhibition -encoding: irrelevant material enters WM decreasing space for relevant material -retrieval: finding correct response is harder, many competing possibilities -WM uses greater bilateral prefrontal activation -overlap of activation in verbal and spatial areas in older people, these should be encoded separately in young adults

Question 31

examples of hemispheric specialisation in healthy younger adults

Answer 31

verbal - L spatial - R encoding - L retrieval - R recall - L recognition - R

Question 32

hemispheric specialisation in older adults

Answer 32

less of this, more bilateral activation

Question 33

what causes reduction in specialisation with age

Answer 33

driven by decline in function -activity in one hemisphere limits harmful inter hemispheric influence -age related decline in hemispheric inhibition = failure to inhibit opposite hemisphere/irrelevant input, decline in normal competition between hemispheres -integrity of corpus callosum decreases with age

Question 34

how does reducing specialisation with age protect function

Answer 34

-cooperation between regions = compensation -better to work tog when demand is high and resources low -to counteract decline older adults use both hemispheres rather than dominant one -if this was the case we would expect to see increased performance as all resources are being pulled together

Question 35

research for bilateral activation in older adults

Answer 35

cabeza et al 2002: older adults that perform well have bilateral activation

Question 36

what are the 4 major models of brain ageing

Answer 36

PASA HAROLD CRUNCH STAC

Question 37

what is PASA

Answer 37

posterior anterior shift in ageing (grady et al 1994) -brain reduces activity in posterior regions and shifts dominance to anterior regions

Question 38

what is HAROLD

Answer 38

hemispheric asymmetry reduction in OLD age (cabeza 2002) -aims to counteract decline rather than being caused by it (compensation)

Question 39

what is CRUNCH

Answer 39

compensation related utilisation of neural circuits hypothesis -reuter lorenz and cappell 2008: pre frontal over activation represents narrowing of focus to support most specific process

Question 40

what is STAC

Answer 40

scaffolding theory of ageing and cognition -Park and reuter lorenz 2009: age related reorganisation indicates formation of alternate goal oriented neural circuits to compensate grey matter volume loss

Question 41

what can be done to mediate neg impact

Answer 41

colcombe and kramer 2003 -aerobic exercise supports executive function in ages 55-79 -normal patterns of decline can be altered in accordance with fitness levels resnick et al 2001/2003 -grey matter loss mediated in healthy indivs -declines in white matter decrease in the super healthy