Adolescence

Question 1

what is adolescence

Answer 1

transistional phase between child and adulthood

12-18y/o typically - characterised by changes physiologically, cognitively and socially

Question 2

adolescence in LDM

everitt/casey et al

Answer 2

characterised by heightened reactivity in the sub-cortical limbic regions
ie VS + amyg to pos and neg valenced info
disproportionately more risk-taking and novelity seeking

may depend on disproportionately hyperactive reward system in consummatory approach beh and/or hypoactivity/protracted development of cortical control systems

• may play a role in the development of affective disorders(ernst et al)

Question 3

define impulsivity

Answer 3

broad construct
poor sc, risk taking, sensation seeking
poor temporal foresight - poor delay of grat

assoc deficits in motor control, attention and reward-related decision making

Question 4

LDM changes in development

Answer 4

as get older - must temporally bridge reciept of the rewards - requires temporal foresight

learn how to learn - focus on the outcome of behaviours in the future so that via experience we can learn from our mistakes (PE-) and our successes (PE+)
- allows us to learn how to navigate the world and become independent

Question 5

different between the young and the old

Answer 5

young - more diverse and broad experience of the world - explore and optimise what they can learn and what they can get from it

older -balance between cog function and ability alters - narrower function of interest
embedded in different way - focus on what achieved and maximise collective outcome of what already have

Question 6

cognitive changes in adolescence

Answer 6

abstract reasoning
-needed for temporal forsight, and ability to plan and improve selves

heightened emotional reactivity
- sensitive to gains and losses - influences how we integrate our beh with our environment

risk taking/novelity seeking

• want to learn and explore the world
• keen to individuate

**VARIABLE TO INDIVIDUAL DIFFERENCES

Question 7

pauss et al

psychopathological vulnerabilities in adolescence

Answer 7

peak age onset of mental health disorder = 14
(national comorbidity survey)
ie anxiety, bipolar, eating disorder, psychosis

onset related to abnormal/exaggerated typical adolescent maturational changes in concert with psychosocial/bio/environ factors

ie neural changes not adequately achieved = risk of cog/affect/addict disorders

Question 8

describe grey matter

Answer 8

cell bodies of neurons

involved in information processing

Question 9

describe white matter

Answer 9

axons and fibre bundles wrappen in myelin sheath

communication between brain regions for neurotransmission

Question 10

gied et al

describe

Answer 10

large scale longditudinal MRI structural brain development study
89 males 56 females
4-22y/o
total of 243 scans

Question 11

gied et al

findings

Answer 11

volume of white matter increased linearly with age
-less in f>m
changes in volume of cortical gray matter were nonlinear and regionally specific
- Gray matter in the frontal + parietal lobes increased during pre-adolescence followed by a decline during post-adolescence that resulted in a net decrease
in volume
- Temporal-lobe gray matter followed a nonlinear developmental course- max around 16-17 with a slight decline thereafter
Occipital-lobe gray matter increased linearly over the age range, without evidence of significant decline or leveling.

Question 12

gied et al

functional significance of findings
WHITE MATTER

Answer 12

linear white matter increase = intuituve

more myelination, axons and efficient communication across diff regions of the brain

Question 13

gied et al

functional significance of findings
GREY MATTER

Answer 13

grey matter change is counterintuitive

when greater in size - more arborization (branching of dendrites - richer)
reduction infers pruning - removal of dendrites and connections not being used - make simpler and more efficient

use it or lose it - remove connections that no longer need - dont expend energy in maintaining them - die off

EXPERIENCE DRIVEN PRUNING

Question 14

gogtay et al 2004

describe

Answer 14

5-20 y/os MRI over 8-10 years

statistical model for gray matter density
human cortical development visualized across the age range in a spatiotemporally detailed time-lapse sequence

Question 15

gogtay et al 2004

results

Answer 15

pruning as early as 4/o
Parts of the brain associated with more basic functions
matured early: motor and sensory brain areas matured first, followed by areas involved in spatial orientation, speech and language development, and attention (upper and lower parietal lobes).

Later to mature were areas involved in executive function, attention, and motor coordination (frontal lobes). The frontal pole, involved in taste and smell processing, and the occipital pole, containing the primary visual cortex, also matured earlier
last = dlPFC

Question 16

explanation of gogtay and geil in light of adolescent behaviour

Answer 16

may exist conflict between cog control processes
struggling to communicate developmentally between subcortical/limbic ‘hot’ areas and cortical/prefrontal cognitive control ‘‘cold’ areas

heightened emotional reactivity a likely consequence of early maturation of subcortical brain areas such as the amygdala

Question 17

ernst et al

triadic brain

Answer 17

continuum between systems facilitate approch to reward/pos outcomes and avoidance of punishment/neg outcomes

assumes that motivated behavior results from the
balanced of three systems:

(1) approach (reward-driven) - goal-seeking behavior
in response to cues of reward

(2)avoidance (harm-avoidant) - withdrawal from aversive cues

(3) regulatory -
cog control - orchestrate relative contribution of the approach and avoidant systems
supervisory/ modulatory control of behavior.

Question 18

ernst et al
triadic brain

model - brain regions

Answer 18

Approach:
dlPFC
VS (NAcc)
DA

Avoid:
amygdala
temporal pole
serotonin

Reg:
PFC

Question 19

ernst et al
triadic brain

model - in adolescence

Answer 19

clinical imbalance between affective and cogntiive maturation
maps onto the structural deveopment of the adolescent brain

hyp: protracted development of control regions of PFC and early maturation of reward and emotion centres = imbalance
- behaviour is driven by hypersensitivity to pos + hyposensitivity to neg cues - beh appears underregulated

response of VS increase – more susceptible to reward
AMYG less sensitive to threat - More likely to take risks
Connections from PFC to systems are weaker than in adults so less regulation of behaviour and more likely to respond to emotional response and not make the same cognitive assessments of risk

Question 20

experimentally studying the adolescent brain

Answer 20

longditudinal/cross sectional MRI brain scans

gonogo- look at emotional responsivity + fmri

temporal discounting paradigms - impulsivity

iowa gambling task - decision making paradigms

Question 21

hare et al
testing the triadic brain

method

Answer 21

go no go on 60 children, adolescents and adults

aim: investigate spike in emotional reactivity in asolescence predicted by the triadic model

response to happ fear and neutral faces (RT) and fMRI - alt go/nogo across trials

Question 22

hare et al
testing the triadic brain

results - behavioural

Answer 22

faster RT for happy > fear, with adults and adol faster to respond than children

slower responses by adolescents and children for fear faces > adults

Question 23

hare et al
testing the triatic brain

results - anxiety

Answer 23

habituation for fear in amyg less prevalent in more anxious adolescents

vPFC activity heighten in early>late to fear in less anxious adol and more anxious adults
no diff in early>late activity for anxious teens and less anxious adults

lower vPFC in less anxious adults (+more in less anxious teens) despite rapid amyg habituation may mirror more efficient reg of amyg in adulthood - require less prefrontal reg

less functional connectivity between amy and vPFC assoc with higher anxiety + influenced by emotional context

Question 24

temporal discounting procedures

Answer 24

quantifies the ability to refrain from immediate reward in favour of delayed/LT ones
involves temp foresight and ability to delay grat - mental time travel of future value
reward devalued as a function of its delay
- steepness that one discounts reward considered proxy of impulsivity
- inversely proportional to the ability to delay gratification

Question 25

christaou et al (1) temporal discounting in adolescence method

Answer 25

fmri - all males - adol + mid adulthood hypothetical discounting task - monetary delayed rewards chose between £0-100 immediately, or fixed £100 available after a week/month/year

Question 26

christaou et al (1) temporal discounting in adolescence results - beh

Answer 26

adolescents discounted more steeply as a function of delay - subj value of £100 more steeply discounted in adol>adults area under the curve - maintain geometric features of the temporal discounting curve (steepness/height) - large individual differences but linear increase in ability to temporally discount - become more able to wait for delayed reward as mature over adolescence

Question 27

christakou et al (1) brain areas associated with developing ability to delay gratification

Answer 27

vmPFC and enhanced coupling with inferior prefrontal cortices inversely assoc with steepness of discounting - supports the development of foresighted beh strength of connectivity between vmPFC and VS assoc with age dependent increse in area under the curve - ability to delay grat frontoreg influence redirects decision making away from the pursuit of immediate rewards as VS hyperresponsivity, and towards context sensitive eval of delayed alt in older individuals

Question 28

christakou et al (1) results - brain areas

Answer 28

reductions with age: vlPFC, VS, insula, MTL + posterior/parietal cortices for both immediate and delayed choice ++++ imediate also: reduced dACC with age reductions assoc with improved delay with age: VS, insula and ACC

Question 29

christakou et al (1) what is context sensitive eval

Answer 29

the adaptive incorporation of information -higher order ie freq, cost, LT impact - integrate calculations to determine appropriate discounted value **not just looking at the immediate absolute value of a reward

Question 30

christakou et al (2) method

Answer 30

iowa gambling task + fMRI in adol and adults 4 cards: 2 safe, 2 risky

Question 31

describe iowa gambling task

Answer 31

requires foregoing high rewards that notheless have a long term loss (risk) in favour of modest rewards which accumulate into long term gains (safe)

Question 32

christakou et al (2) results - beh

Answer 32

task performance improve with age and stabilise into adulthood more stable shift in preference towards the safer decks adol prone to approch risky decks but shift as mature - learn from reward and punishment outcomes

Question 33

christakou et al (2) results - PE

Answer 33

high sensitivity to PE+ predict risk high sensitivity to PE- predict safe differential responsivity to PEs as mature: adults more sensitive to PE- asol no diff in learning from either reduced sensitivity to PE+ characteristic of maturation and experience heightened sensitivity to PE- strengthened in adol - may be dev marker - adol beh more PE- (worse than expected sensitivty) than pe+ (better than)

Question 34

logistical problems with investigating asolescence

Answer 34

``` 'age range' age range is differential across studies what constitudes what development on a continuum too many individual differences ``` a lot of inconsistencies - are the results generalisable to all? / generalisable across studies?

Question 35

problems with the paradigms used in adolescent research

Answer 35

when using monetary reward paradigm in ounger ages - is it the same as when using on older adults who have experience of money and value - differential value at different ages likely to have different consequences on decision making

Question 36

problem with adolescent research lab studies

Answer 36

doesnt take into account the amount of changes going into development and the impact of a range of different assoc factors such as environ/culture/puberty/gender low eco validity - how act in real life?

Question 37

why may children not present a similar response in VS to rewarding cues

Answer 37

children may rely on the surrogate decisions: parents or carers adolescents accumulate the arsenal of cognitive capacity, self-knowledge, and world experience to orchestrate increasingly independent and individual behaviour

Question 38

triadic brain approach system

Answer 38

approach to rewards - stimuli which individuals strive to approach underlies goal-seeking behavior in response to cues of reward -typically associated with positively valenced emotions. goal-seeking behavior

Question 39

triadic brain avoidant system

Answer 39

avoidance of punishments - stimuli which individuals strive to avoid. - underlies withdrawal from aversive cues and is typically assoc with neg valenced emotions

Question 40

triadic brain regulatory system

Answer 40

PFC supporting exec functions for planning and execution of complex behavioral sequences ie planning, inhibition, switching, wm the regional specificity of behavioral modulation may differ as a function of cognitive and emotional contexts and demands - nature of the circuits that balance approach vs avoidant systems is complex likely candidates: mPFC, ACC, vPFC, OFC These regions play important roles in the control of motivated behavior, such as conflict monitoring (ACC), adaptation to changes in stimuli value (OFC) and self-monitoring for (mPFC)

Question 41

define temporal discounting

Answer 41

describes the observation that the subjective value of a reqard declines as a function of the prospective delay to its attainment ainslie

Question 42

# define pruning pauss

Answer 42

a process by which 'redundant' synapses which are overproduced in the early years of life are diminished structural and functional maturation of neural paths permit ideal conditions for development of successful cog, motor and sensory functions into adulthood

Question 43

brain regions thought to be assoc with TD

Answer 43

limbic frontotriatal circuitry in reg of reward discounting via DA/serotonergic input ventral striatal activation tracks value of delayed reward - neural responsivity invesely correlated with steepness of discounting (ballard et al) protracted PFC dev believed to mediate responsivity to motivational/emotional/social cues - reflection of percieved impulsivity in young adults

Question 44

Christakou (2) Results - PE BRAIN

Answer 44

neural rep of PE maturation - vm/dl PFC - predictive of performance degree of PE rep in vmPFC assoc with better performance in adults degree of PE rep in vlPFC + VS assoc with worse performance in adol top down vmPFC on VS (christ..1) reflected by pos correlation between performance and PE mod vmPFC in adults (vs vlPFC worse in adol)

Question 45

christakou (2) results vm vs vl pfc

Answer 45

vmpfc - represnts value of stimuli/actions with contextual input vlPFC - fundamental in assoc learning - lacks contextual sophistication adolescents may lack contextualisation of reward in the vmPFC and rely of vlPFC/VS to provide counterproductive values in stiuations where need to elicit TD

Question 46

hare et al test triadic brain results - amyg and pfc

Answer 46

adolescents had heightened amygdala activity than children and adults, specifcally to fear>calm faces in early trials (habituation) no sig diff between fear and happy amyg assoc with slowe RT for fear vPFC assoc with faster RT to fear inverse correlation between vPFC and amyg assoc with habituation of amyg acitivty trength of coupling between vPFC and amyg correlate with habituation of amyg in adolescents - can suppress competing response but must recruit prefrontal more so than adults

Question 47

hare et al results - explain in adol

Answer 47

competition between subcortical emotional processing systems and immature top down prefrontal control systems - important to guide behaviour in emotional context elevated amyg + protracted prefrontal in terms of both reduced grey matter density and heightened myelination to other brain regions in asolescents may underlie individual diff in emotion reg