The brain is responsible for the creation of language,
thought, attention and consciousness, memory and imagination – yet no extensive
knowledge of its structure has provided a clear insight on how the brain
develops and how early experiences affect that development (childwelfare.gov, 2015).
Adolescence is the phase between late childhood and
adulthood. During this phase adolescents thrive on new experiences, powerful
emotions, sometimes putting their lives at risk. Neuroscientific explanations
have presented correlations between academic and emotional behaviour. Enabling
neuroscientists to specify way of intervening adolescents in a social and
Large scale longitudinal structural neuroimaging is a highly
compelling tool in developmental neuroscience due to its capability in
measuring anatomical change in an individual over time – providing essential
insights in characteristics of human maturation, and in ways which
neurodevelopment varies in respect to sex, cognitive function, genetic profile
and disease status.
Self-regulation is the ability to control behaviour, cognition
and – failure of this is related to a range of neuropsychiatric issues (Fjell, 2012)
More specifically, decision making and control has been
linked to academic success and social adjustment. In support of this, lower
performance on the flanker task has shown poorer social interactions, leading
to peer rejection and more disruptive behaviour in classrooms (Fjell, 2012). . Investigation on
relationships between cognitive control via MRI and DTI by Fjell et al. found a
correlation between brain areas and regulatory problems in different
neurodevelopmental conditions – negatively impacting performance on cognitive
control tasks and daily life.
Harmful environments or prenatal substance exposure have
shown structural differences in the prefrontal and right anterior cingulate
cortex; causing psychopathological conditions such as ADHD. By studying the effects of prenatal
substance exposure (alcohol/drugs), neuroscientists can discover solutions to treat/prevent
psychopathological conditions within early childhood by introducing cognitively
enriched environments. For example, studies of environments in rats have shown
that greater complexity within an environment before or after brain damage in
developing and adult rats (Hannigan et al, 1993), strengthened the
process of recovery of cortical impairment of the brain (Jack P, 2000). In other words,
rats prenatally exposed to substances can gain from the positive attributes from
reinforced environments. (Hannigan et al, 1993).
Moving from animal studies to research the
neurodevelopmental features of human cognitive; executive and impulsive
development is a very time consuming, especially when this study would provide
more concrete evidence on cognitive control through longitudinal studies.
Neuroscientists have discovered a lot about the structure
and function of the brain. Majority of focus of research was on early
development of isolated cortical locations in the human brain. Now, with the
use of new imaging technology, neuroscientists can examine normal brains and
brains of normal people throughout their lives, with regards to sex and how
various cortical regions mature with respect to one another (Armin Raznahan, 2011).
In short, the development of prefrontal cortexes are vital
for cognitive control during structural development during adolescence.
Raznahan found that architectural changes of the developing brain had no structural
correlation. Whereas, great maturational coupling across the cortices provided
a clear correlation between frontal and temporal cortices in the brain, in
contrast to sensory cortices: and then identified the rate at which cortical
regions were most tightly coupled (Armin Raznahan, 2011).
What’s more is that by separating sex effect on prefrontal
maturations, it’s possible to identify sex difference in neurodevelopmental
mechanisms, in relation to cognition and behaviour. Female adolescents were
shown to have a distinct relationship between frontopolar cortex and left
prefrontal cortex maturations whereas male adolescents don’t. Suggesting that
the link between functional and maturational coupling may be a common property
of the brain, concerning sex differences and different cortical functions
during problem solving tasks (Steinberg, 2010) requiring extensive coordination of
multiple higher cognitive processes (Armin Raznahan, 2011).
during late childhood and adolescence
In developmental science, longitudinal studies have provided
evidence of maturational coupling of the brain occurs during adolescence – when
the overall number of synapses decrease to their adult levels, there is an
increase in white matter and changes in
neurotransmitter systems (Jonrad, 2013). Thus, the cognitive
functioning and physiological processes during maturation is more complex than
As mentioned in cortical development, the organisation of
cortices during adolescence affects anatomical and physiological regulations. By
understanding the link of early or late exposure of pubertal hormones to child
behaviour and mental disorders will aid in the recognition of influence of
social and cultural aspects of young people. Recent findings have tried to
establish the role of pubertal hormones on brain structure and functional
development (Simmons, 2014) through a group of
children who differ in their exposure of adrencheal hormones.
In summary, this research has introduced the investigation
on how minimal or over exposure to pubertal hormones may have a role in the
development of mental disorder symptoms. Although recent findings is scarce in
this area, this study has begun to recognize the association between potential
phases of pubertal brain development and physiological processes, unfortunately
the impacts of these have not established yet.
Suppressing risky behaviour on a neurophysiological basis
has been proven difficult. Therefore, it would be wise to allow adolescents to
express their emotions in a safe environment, while increasing their social
experiences and interactions without risky behaviours through regulatory
legalisation (Jonrad, 2013). By doing so adolescents are surrounded
by positive examples, for example: a teenage character on a TV show may express
clearly their suicidal feelings to parents or guardians confidently.
Laboratory studies of adolescents using hypothetical
scenarios without peer influence may not provide a real life understanding of
real-world decision making (Paus et al, 2008). As mentioned before (Hannigan et al, 1993), animal studies help
answer many questions on adolescent brain development and its influence on
disease – by modelling the adolescent phase in animals, scientist can begin to
understand the early symptoms of psychiatric disorders such as depression.
Improvement in cognitive control and self-regulation may
depend on maturation of great long distance long distance white matter fibres
and prefrontal structures being involved. Neuroimaging techniques implied that
the anterior cingulate area showed a relationship with white matter tracts and cognitive
control. Although, the cross sectional design used prevents the involvement of
individual personalities and differences on making depictions of relationships
between set variables. The lack of longitudinal studies also prevent
conclusions based on self-regulations to be replicated.
Other factors affecting brain development could be hormonal
changes. However the research on this topic are limited. By investigating the
neurobiological and behavioural issues of late or early exposures of hormones
could change the understanding of pubertal risks. E.g. findings of animal
studies have shown cannabis during adolescence has can cause permanent
cognitive impairment and structural changes in the brain, compared to adult
cannabis users (Jonrad, 2013). In other words, the plasticity of the
brain during adolescence causes vulnerability towards environmental influences.
Despite no link between behavioural changes and brain structure
and cognitive control has been made, findings through neuroimaging techniques (DTI,
CT scans and Functional MRI) help develop models on cognitive and
neurophysiological processes. In reference to cortical development, CT changes
have demonstrated strong correlations between cortical regions (Armin
However, CT changes on a cellular basis are not understood, so it’s not
possible to know if physiological changes are occurring at the same rate in
males and females. Therefore, the correlations between the rate of CT changes
in two cortical regions may or may not show that the change is due to a common
During childhood cognitive control develops rapidly
accompanied with prolonged development during adolescence. This implies that
self-regulation has an overlapping spectrum of normal to neurodevelopmental
disorders (Fjell, 2012). Insinuating that
there’s a wider time window of greater reorganisation during brain maturation (Evans et al, 2012).
Findings through neuroimaging techniques help understand
when and how refinement of normal development occurs and, may increase efforts
to prevent or treat disorder (Paus et al, 2008).
Until now, cognitive neuroscientists haven’t addressed the
importance of environmental influences and organisation of the brain (Jonrad, 2013). The integration of
animal and human studies use both neuroscience and behavioural approaches, and considers
the negative impacts of early stress and trauma (Jack P, 2000). The experiments on
rats presented that younger rats had an awareness for their environment;
suggesting that the removal from complex environments can negatively affect
development, with the brain trying to reorganise itself.
In sum, neuroscientific research on brain development provides
few insights on how early environments can begin to have an effect on
development. Evidence shows that brain development begins before birth, and is
prolonged into adult years, to gain experience for development and functioning.
Majority of brain development involved in cognitive control and social
development either suggests that critical/sensitive periods haven’t been fully
explored or the brain still desires new experiences throughout development.