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Developmental - Adolescence - Intro (Y1) - Coggle Diagram
Developmental - Adolescence - Intro (Y1)
The unique developmental period of adolescence
Adolescence - a period of physiological, psychological and social transition between childhood and adulthood; as soon as you reach the height of an adult, we perceive them to be the same maturity and intelligence
Adolescents are therefore expected to behave like adults but without the tools to do so
As a developmental period - cognitive abilities are continually developing between the ages of 4 and 20+ years - early years about learning techniques, complex content comes later in adolescence)
puberty also occurs, and so physical growth, hormonal changes, peer orientation and social environments all change
It is a time of increased mental health problems due to cognitive development changing alongside puberty (Haller, Cohen Kadosh, Scerif and Lau (2015)
Most plastic brains, optimal learning period
Respond to rapidly changing psychosocial factors - Blakemore (2008), Burnett et al (2013) and Cohen Kadosh (2011)
Social environment
Expectations of others
Physical appearance
Impressive cognitive development and prime period for learning - cannot make the most of this if we are distracted by anxiety over change
Strong orientation towards peers
increased risk taking and novelty seeking
Most change in society comes from young people, and so it is in the societal interest to preserve adolescents so they can do this - young people should be given the opportunities they need to allow society to renew
Increased risk of mental health problems:
anxiety disorders developing between 5-20 years old
Impulse control disorders between 5-15 years
Mood disorders - key onset in late teens, alongside substance use disorders and psychiatric disorders
2/3 of mental health problems start in adolescence - estimates of the number of mental disorders globally for girls and boys aged 10-14, 15-19 in 2019, with over 80+ boys and girls impacted
Prevalence - anxiety and depressive disorders (42.9%), Conduct disorders (20.9%), ADHD (19.5%), idiopathic developmental intellectual disability (14.9%), remaining mental disorders (9.5%); UNICEF statistics
Higher risk of lifelong disorders if it begins in adolescence, due to the threat circuitry that is emerging during a time of high plasticity
Large co-occurrence of mental health issues
If you have a super threat network due to anxiety, this can lead to less cognitive capacity for learning and other pathways to develop, making you more sensitive to other large emotional dysregulation, such as increasing hostile attribution
Brain sets up networks for the stress environments we are in, and we have to correct these by providing better environments to fix maladaptive networks
Podcast on adolescent brains -
https://www.theguardian.com/science/audio/2018/mar/23/inside-the-secret-life-of-the-teenage-brain-science-weekly-podcast
Risk taking brain patterns remain constant across cultures despite societal expectations of adolescence - universal developmental patterns of it increasing in teenage years and decreasing in 20s
Need for independence and powerful influence of social factors on plasticity and learning
Social brain undergoes most change in this time - changes in the way the social mind works and the ability to take other's perspectives is still undergoing development
Because they look like adults, we place unfair adult expectations on them (mental illness?)
Social influence on risk perception - all age groups show a social influence effect - 12-14 year old adolescents are the most influenced by teenage risk ratings than adults, whereas all other age groups were more influenced by adults
Teenagers care more about social norms than health risks - social norm focus is the best way to get teenagers to change their behaviorus
Brain tracks both developmental and chronological age
3/4 of mental illnesses appear first before the age of 24
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
file:///Users/katie/Downloads/Required%20reading%20Tamnes_2013.pdf
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
file:///Users/katie/Downloads/Additional%20reading%20Cohen%20Kadosh%20_2013.pdf
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
file:///Users/katie/Downloads/Additional%20reading%20Johnson%20_2015.pdf
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
Nutrition and the gut microbiome
Improving nutrition in adolescence - WHO recommendations of reduced sugar, reduced salt intake and supplementation of iron and iodine (Sparrow et al, 2021)
Humans are colonised by over 30 trillion microorganisms and our body has adapted its organs in symbiosis with these
The microbiome in the gut is dominated by bacteria, archaea, yeast, viruses and protozoa
Microbiome - refers to the combined genetic material of these organisms
The gut-brain axis and the microbiome - gut microbiota influence initial brain development but also brain responsiveness and function across the life span
Gut brain axis - bidirectional communication via neural, endocrine and immune pathways - vagus nerve
Gut microbial composition has been shown to regulate gene expression and the release of metabolites in the brain (glutamate or GABA)
It has been shown that if something is wrong in the gut, there is dybiosis - significant reduction in bacterial diversity, and can lead to psychological abnormalities as common as mental illness
For example, in adults the gut microbiota has been related to atypical social functioning in autism, and symptoms of anxiety and depression
The period from childhood to adulthood has multiple, critical windows where microbioata help fine tune the gut brain axis, with long lasting consequences for the individual
Gut microbiome is part of a complex system (Sarkar et al, 2012) - exchange of bacteria with environment is important for preventing mental illness, through exercise, sleep, diet and social interaction
Microbiome differs as a function of lifestyle - those in non-industrial societies have a qualitatively different microbiome to those in industrial societies, and if you move from one to another, your gut changes within 12 months due to food etc (New Mexico stool samples have the same microbiome as the non-industrial society) - Wibowo et al 2021
Use of interventions in gut microbiomes as an intervention for mental health - Probiotic intervention in young women (Johnstone et al, 2021)
64 female participants, aged 17-25 years
4 week course of prebiotics (galacto-oligosaccharides, GOS, or placebo of maltodextrin)
Comprehensive behavioural and psychological assessment
Stratified into high anxious and low anxious groups
Nutrition diary
Stool sampling for microbiome sequencing
Found those who are taking the supplements had more change than the placebo group in their microbiome, and there was also a decrease in anxiety levels of those in the prebiotic group
There was also a change in diet from all participants (brain to gut direction) - prebiotic participants cut down on all sugar intake without knowing and also cut down in carbohydrates - intervention which affected gut impacted diet and behaviour
These research protocols are developed (Cohen Kadosh 2021) through asking young experts on psychobiotics
66% said that they attempted to use diet to manage mental well being, and asked for good scientific evidence for how this helps behaviour and clear instructions on what to do and the relevant benefits
Could be a supported intervention by young people, those whom it targets
Cohen Kadosh, 2020 - Prebiotics: file:///Users/katie/Downloads/Required%20reading%20Cohen%20Kadosh%202020.pdf
The use of prebiotics to improve gut health and diet has been linked to a decrease in feelings of anxiety and depression, but only in the groups that experience high levels of it - little change in baseline groups
Dybiosis in adolescents can lead to trait anxiety and long lasting impacts on mental illness - although gut brain axis is bidirectional, it may be that nutrition fine tunes these systems
Probiotics influence the gut brain axis through endocrine, immune and neural pathways - prebiotics influence the brain through glutamate and GABA release (excitatory and inhibitory neurotransmitters)
Greater diversity in GOS group - beneficiary to preventing the growth of non-beneficial bacteria
More stable microbiome - leads to less stressors, as microbiota instability is linked; gut health may be able to restructure biological mechanisms, but this much is yet to be determined in terms of biological mechanisms
Issues of sample size, placebo effects, mirroring of groups, lack of control over hormone contraceptives which could impact mood