Brain Development
The Brain Continues to Grow Throughout Adolescence
Until recently, increased hormone activity during
puberty has always been the blame for the characteristic behaviours
expressed by teenagers at home and at school. Although different types
of hormones are responsible for the many changes that occur during
adolescents, including sexual maturation and acne, it has now know that
increased myelination of the frontal lobe also plays a major role in
teenage behaviour. The frontal lobe, as the name suggests, is an area of
the human brain located anterior to the parietal lobe (Figure 1). This
area of the brain is involved in: judgment, impulse control, behavioural
spontaneity, reasoning, planning, sexual behaviour, long-term memory,
and language, and is often referred to as the seat of 'executive
functions' (Teenage Brain, 2008). Furthermore, myelin is a soft, white,
fatty material that insults a neuron by forming a sheath around the
axon, thus, serving as a protective barrier. As the brain processes
information, the development of myelination within the nervous system
adds to the speed and efficiency of messages as they are transmitted
(Auger & Rich, 2007).
Figure 1. The human cerebral cortex.
Each side of the cerebral cortex is divided into four lobes, and each
lobe has specialized functions. Some of the association areas on the
left side (shown here) have different functions than those on the right
side. For further information on the four lobes displayed, click on the
lobe of interest.
Prior to recent studies, research had shown that the
brain would overproduce gray matter during prenatal development to the
first 18 months of life, and then would undergo pruning. These
discoveries were heavily challenged in 1999 when a group of scientists
discovered that a second wave of gray matter is produced just prior to
puberty in the frontal lobe (Castellanos et al., 1999). This suggests
that the frontal lobe is not fully matured during a person's adolescent
years. To confirm this discovery, researchers compared MRI scans of
young adults, 23 to 30, with results obtained from teenagers aged 12 to
16 (Holmes et al., 1999). They looked for signs of myelin,
because more myelin would imply greater development within the gray
matter. As expected, areas of the frontal lobe showed the largest
differences between young adults and teens. This increased myelination
in the adult frontal cortex likely relates to the maturation of
cognitive processing and other "executive" functions (Teenage Brain,
2008). In other words, prior to becoming an adult, sense of reason and
the control of impulses have yet to ripen.
Figure 2. Structure of a neuron.
The knowledge of this information will highly benefit
all secondary school teachers and intermediate-level elementary school
teachers as they try to piece together their students' complicated and
diverse ways of thinking. Educators who are aware of the physiological
aspects of the brain will know better than to criticize a student for
not thinking ahead before making an unwise remark in class. Adolescence
have a difficult time trying to reason about a more sensible way to do
things, partly because their frontal lobe has yet to develop. Therefore,
it is easier for an educator to understand these circumstances and
accept that most students do have a hard time foreseeing the future
consequences for their faulty actions (Pertler, 2007). On the contrary,
lack of this knowledge may prevent an educator from handling this
situation more professionally; that is, they may become short-tempered
and unmotivated when confronted with intolerance in the classroom. The
frontal lobe also plays an important role in retaining long-term memory.
That said, a teacher should regularly update the homework board and
remind students of any assignment due dates. Finally, since emotional
responses are processed in the frontal lobe, attitudes towards learning
can be seriously influenced or seriously comprised by negative emotional
states during this myelination period (Auger & Rich, 2007). Therefore,
educators must be mindful of the importance of promoting a positive
emotional learning environment for students of all ages through
motivation and encouragement. This will keep their learning experiences
positive and improve their emotional status, stimulating them to want to
learn.
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