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Adolescence - Intro (Y1) - Coggle Diagram
Adolescence - Intro (Y1)
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Brain development
Brain development is protracted - 24 years + to fully develop, with main sensory systems being ready at birth / infancy but cognitive control, flexible learning and social cognition developing throughout life
- This is beneficial for allowing us to continually move and change throughout life, and we have a long developmental window with which to add new skills
- Adolescence is the development of social cognition, cognitive control and flexible learning
- Different regions develop at different rates - allows individual to respond flexibly to changing environments and challenges (frontal lobe)
What changes -
Grey matter (neuronal bodies) decrease during adolescence
- This is due to synaptic pruning - use it or lose it principle
- Results in more efficient, fine tuned circuits
White matter - increases during adolescence and continues to do so throughout life (nerve fibers and axons)
- Our connections
- During development, the brain's axons become increasingly ensheathed and so signalling improves and becomes more reliable - if a skill is not sued, or a behaviour is not practised, the myelination is removed in these networks
Tamnes et al, 2013 - high rate of change in adolescent brains between 8-22; ventral temporal stream and visual cortex develop first, then the prefrontal, frontal cortexes and limbic system
- Longitudinal study of volume changes - compared ageing and adolescent groups
- Lateral cortical changes found to be similar
- Frontal lobes of cognitive ability develop rapidly after sensory systems are completed - more abstract spatial thinking areas are developed in adolescence
- Some of the risk taking behaviour can be attributed to these brain regions developing later than perception, emotional regions (attachment) and the regions for behaviour control only just starting to develop in adolescence
- Medial temporal reduction in ageing not seen in development
- Converging patterns of change in ageing and adolescent groups, particularly in the medial prefrontal cortex, suggest that later developed cortices are especially vulnerable to atrophy in ageing
- Changes are dense and numerous in the youth in a number of brain areas involved in emotional regulation, memory, control, motor control, linguistics and cognitive ability
- Differing rates of change across brain structures and regions in development, as well as accelerating changes in cortical frontal areas and decelerating change in posterior areas suggesting that maturation proceeds in a posterior to anterior direction
- Overlap and spatially distinctive areas between the two groups - indicates the areas most vulnerable to atrophy later in life, and the expectation in the medial temporal lobe
- Change allows adaptation to new situations - executive function takes longer, main targets for interventions
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Changing brain networks
fMRI based neurofeedback - Scharnowski and Weiskopf (2015)
- Participants placed in brain scanner, look at stimuli and are presented decision making tasks which provide neural feedback
- We are therefore able to change people's behaviour and observe brain activity, by encouraging down regulation of brain regions (e.g. pain response), reduce cravings; also able to achieve up regulating of other regions
- Being used to train autistic people to look at eyes and shrink brain regions involved in fear and anxiety - changing brain regions to change behaviour
- Adolescents can be brain trained in self regulation
Most commonly targeted control regions - NF used in the up and down regulation of emotional responses in adults
- These interventions affect emotional regulation networks
- Used in clinical populations for those with chronic pain, depression and Parkinson's
- De Charms et al 2007, Linden et al 2012 (and many others)
NF and development:
- shape the setup process of important brain networks - do not need to wait for anything to mature, and if the patient is using the wrong network we can nudge them towards using correct ones - adaptive response pattern
- Excellent temporal and spatial resolution - target brain areas relevant to each developmental stage
- Track plasticity from before and after (structural and metabolite change)
- Can we teach children and adolescents to regulate response in specific emotion regulation regions, and how does regulation affect the wider network - questions needing further research
Feasibility Study - anterior insula, Cohen Kadosh (2017) - pre clinical sample of 17 children and adolescents aged 7-17 years
- Localised task to activate emotion regulation networks
- fMRI based NF to increase responsiveness in anterior insula
- 4 sessions of thermometer against yellow background, whenever the feelings of coping / positivity were felt the thermometer went up - 5 20 second rest blocks, and 4 20 second regulation blocks
- Task - either relax and do nothing with yellow background, or when on green background tap into positive feelings that create a differential activation pattern for right insula by increasing activity - boosting mode of up regulation, and calm down mode of down regulation
- Children very good at regulating and trying to keep temperature positive, which is intuitive; very used to trial and error, takes around 15-30 minutes for them to crack it
- NF regions defined individually and each strategy used to regulate emotions is unique to the individual
- Having an 'unfinished' brain is helpful, as you are able to learn fast is a benefit for adapting and changing regulation
- Up-regulation success.- in right insula, able to boost response in all sessions, and in the left insula, able to boost in 2 of 4 sessions
- Young children are able to control their own brains, making it possible to push interventions to help increase control of these regions and prevent mental health issues, using neurofeedback to tweak brain function
- When asked to up regulate, amygdala activity increased into the right insula, and whenever there was no feedback or no regulation, feedback went from the insula to the amygdala, not the other way around
Cohen Kadosh - plasticity during development, cognitive bias modification and fMRI neuroregulation:
- Brain changes occur specifically during adolescence to allow cognitive development, enable rational thinking and develop complex cognitive strategies for regulating responses to emotional and social stimuli
- Greater plasticity at this age allows for sensitive period criteria to be met, however little is known about the existence of sensitive periods for emotional and cognitive development
- Deprivation socially before adolescence leads to less myelination of prefrontal cortex and behavioural differences - area of brain involved in social interactions and understanding other people's mental states (effects reversible)
- Myelination reflects plasticity
- Interventions developed can be tested to find the optimal plasticity and sensitive period in which to implement them to help adolescents move through periods of emotional difficulty - regulation of emotions
- Adolescents can self regulate emotions - useful for helping mental illness; the more of our time that is spent with mental illness, the more opportunities in our prime learning period that we miss
Emotion processing and regulation develop continually throughout adolescence - identification and categorisation of emotional expressions as well as evaluating and regulating one's affective response
- Individual can respond flexibly to changing environments, which is important for the internal and external changes faced by adolescents
- high vulnerability levels - adolescent anxiety major predictor for anxiety disorders in adulthood
- Adolescence is a sensitive period of plasticity for acquiring successful emotional coping strategies - issues with limbic system and slow development of prefrontal cortex leads to impaired coping strategies
CBM and ABM - cognitive bias modification (or attentional) which aims to modify the automatic processing of an affective stimuli and train participants to systematically direct their attention away from threat-inducing stimuli
- Dot probe task - present neutral and threatening stimuli, then replace one with a target stimuli in the same location - faster orientation towards threat location suggests bias toward threat, whereas opposite orientation signals avoidance
- Modify processing of stimuli to lower anxiety levels
fMRI NF seems to affect the functional connectivity of the regulated area, defined on the correlation between this area and the rest of the brain - up regulation of amygdala associated with increased functional connectivity in frontal areas
- Positive behavioural effects can also be associated with changes in neural plasticity
- NF can impact regulation in a specific brain region, but also the processing flow within a larger network of regions highlights its ability to impact the whole brain - adolescent emotional regulation is possible with activation in areas increasing during up regulation in prefrontal cortexes, and with training also the ventral striatum
- However, effects could be more powerful with a specific cognitive emotional regulation method such as positive mental imagery - use of CBM as a cognitive regulation strategy in combination with NF could improve functioning during periods of exceptional plasticity
Could be used to identify optimal periods, by targeting sensitive ones and avoiding time where disruption potential is high
- Ability to avert maladaptive response patterns, especially in those at risk of psychological disorders by developing tools to shape response strategies during childhood and adolescence
- Could it be used in conjunction with therapy techniques to target underlying biological network issues in disorders - possible drug alternative
- Could be used to improve functioning in both typical and nontypical development, but the use of this to improve typical brains would be an ethical dilemma
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Johnson, 2015 - Brain adaptation and alternative development trajectories:
Four types of brain adaptation in the face of early risk -
- Redundancy - some pathways not needed and are pruned - in ASD, helpful ones sometimes pruned or alternative systems are used for similar functions
- Reorganisation - hierarchy of structures - autism has deficits in executive function
- Niche construction - construct the environment to suit your adaptations; unique attentional style of ASD is the result of the atypical brain adapting to the pace and quantity of sparse information flow
- Adjustment to developmental rate - adjusted to maixmise chances of fitting the environment - too much neural noise in ASD, early environment is poorly predicted and sample, causing anxiety as they lack the ability to predict environments
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In autism - ASD results from nonoptimal synaptic function but intact adaptive mechanisms, leading to behavioral adaptations that constitute part of the ASD symptoms
- It is possible phenotypic variability relates to the degree in which the adaptive mechanisms are compromised by synaptic malfunction
- Neural basis of key symptoms in autism are investigations of the brain's ability to adapt and reorganise in the face of diffuse and wide spread synaptic differences, which occur at earlier points in development and can impact information processing
- Major issue in developmental conditions is selectivity - what conditions make it ASD over ADHD etc; most commonly, the neural systems affected differ in each condition
- However, the genetic overlap causes the actual selection to come in the developmental stage at which the diffuse and widespread neural detuning occurs which determines the nature of adaptive responses and the behavioural traits that emerge as a result e.g. ADHD usually emerges a few years after autism, suggesting it is different developmental responses
May be a larger pool of adaptive syndromes - species typical adaptive processes that underlie the phenotype associated with autism, specifically changes in the connectivity and activation patterns
- Autism requires the study of the interaction between atypical early processing and species typical adaptation responses
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