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BRAIN ARCHITECTURE
MENTAL HEALTH
TEEN MENTAL HEALTH & WELLNESS
BACKGROUNDER: Page 1 of 4
BRAIN ARCHITECTURE
The human brain is one part of our nervous system, which is the control system through which all other
body systems receive their instructions. Much like the engine of a car, the brain is made up of many
different parts. These parts have different functions, but they work closely together, to coordinate
complex thoughts, feelings and behaviours.
BRAIN CELLS
All organs in the body, including the brain, are made up
of cells. Each of the many different cell types in the
brain has a specific function. The most recognizable
type of brain cell is the neuron (see Figure 1). Neurons
are specialized cells that transmit electrical signals,
similar to the wiring in your home.
The brain is made up of 100 billion neurons. Each of
these neurons is connected to at least one other
neuron, forming 100 trillion connections in the brain.
Electrical signals jump from the axon end of one neuron
to the dendrite end of a neighbouring neuron (see
Figure 1). To do this it has to cross a tiny gap called a
synapse. The electrical signals travel between brain
regions at a variety of speeds.
REGIONS OF THE BRAIN
Weighing just over 1 300 g and yet using up to 20% of
the body’s energy, the brain is the powerhouse of the
human body. Contrary to popular belief, humans do not
use only 10% of their brain power. The entire brain is
involved in coordinating internal and external actions
like sneezing, kicking a ball, or texting.
Figure 1: Diagram of a neuron & Schwan cell. The
neuron has dendrite branches on one end and
the axon terminal at the other. The ‘Schwann’
cell is a separate cell in charge of making a fat
coating (called the myelin sheath) around the
neuron. This is like the plastic/rubber housing
around the wiring in your home. Electric current
flows in the direction of the red arrow, from cell
body to axon terminal.
Source:
https://commons.wikimedia.org/wiki/Neuron#/m
edia/File:Neuron.svg
The brain is made up of two hemispheres (left and right sides of your brain), which contain six distinct
regions (see Figure 2 on next page).
Frontal Lobe: This lobe is located at the front of the brain. It is responsible for actions like critical
thinking and planning, feelings of reward and motivation, our knowledge of our self-identity and the longterm storage of memories.
Parietal Lobe: This lobe is located near the back of the brain. It sits behind the frontal lobe and in front
of the occipital lobe. The parietal lobe is responsible for sensing proprioception (movement in space in
relation to the body), touch, pain and temperature. It is also responsible for language processing
(interpreting the rules of language).
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BRAIN ARCHITECTURE
MENTAL HEALTH
TEEN MENTAL HEALTH & WELLNESS
BACKGROUNDER: Page 2 of 4
Occipital Lobe: This lobe is found at the back of the brain. It contains the visual cortex which is
responsible for vision. Damage to this area can lead to blindness, hallucinations and seizures (called
occipital lobe epilepsy). The visual system is contralateral, which means that images perceived in your
right eye are processed in the visual cortex on the left side of your brain and vice versa.
Temporal Lobe: There are two parts of the temporal
lobe - one on each side of the brain – in the part of the
head that people call their temples. This lobe is
responsible for learning, memory, understanding the
meaning behind language and navigating through
obstacles in the surrounding space.
Cerebellum: Under the occipital lobe sits the
cerebellum. This structure is best known for its role in
fine-tuning muscle movement. Disorders of the
cerebellum result in disabilities in balance, posture and
motor learning.
Brainstem: The brainstem is the part of the brain that
connects the base of the brain to the spinal cord. The
brainstem acts as the coordinating centre which
connects the brain to the internal organs and the rest of
the body. It also helps coordinate involuntary actions like
breathing and heart rate.
Figure 2: Lobes of the human brain (from left to right):
Frontal Lobe (blue), Parietal Lobe (yellow),
Temporal Lobe (green), Occipital Lobe (pink),
Cerebellum (white), Brainstem (white beside
cerebellum). Source:
https://commons.wikimedia.org/wiki/Lobe_of_th
e_brain#/media/File:Gray728.svg
Now we are going to dive deeper into the internal structures of the brain to understand how it functions.
INSIDE THE BRAIN
Cerebrum and Cerebral Cortex: The cerebrum is the
large wrinkly part that spans both hemispheres and sits
on top of the brainstem and cerebellum. It is responsible
for coordinating complex functions and voluntary actions.
The cerebral cortex is the outermost layer of the
cerebrum. It is the part known as grey matter (see
glossary below).
Figure 3: Diagram of the internal structures of the brain.
The highlighted area shows a portion of the
cerebrum and the right half of the corpus
callosum. These areas are important for the
coordination of critical thinking.
Source:
https://commons.wikimedia.org/wiki/File:Brain_
human_sagittal_svg
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Corpus Callosum: The corpus callosum is a bridge of
nerve fibres that connects both hemispheres of the
brain. It allows the two halves of the brain to
communicate with one another in order to coordinate
and synchronize activity.
BRAIN ARCHITECTURE
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TEEN MENTAL HEALTH & WELLNESS
BACKGROUNDER: Page 3 of 4
Thalamus: This region is located above the
brainstem. The thalamus is the part that
coordinates all sensory information coming into
the brain. It is also involved in regulating sleep
and consciousness.
B
C
A
= dopamine pathway
Figure 4: Diagram of the internal structures of the brain. The
highlighted area shows the regions of the
hypothalamus, the
thalamus (above
the
brainstem), and the pituitary gland.
Source:
https://commons.wikimedia.org/wiki/File:Brain_hu
man_sagittal_section.svg
Hypothalamus: The hypothalamus sits just
below the thalamus – hence its name. This
region links the nervous system to the
endocrine (hormones) system. It is responsible
for creating brain hormones and controlling the
pituitary gland.
Pituitary Gland: This gland is found below the
hypothalamus. It is a major part of the endocrine
system, and is extremely important during
human development. It is the control centre for
all other hormone glands in the body.
The Dopamine System: Also known as the
reward system, the dopamine system (see
Figure 4 and Figure 5) is critical for the control of
mood and the reinforcement of behaviours. It
consists of the following structures:
1. Hippocampus: This structure is found in
the temporal lobe (see Figure 2 and
Figure 5) and is part of the Hippocampal
formation.
It
is
responsible for
coordinating a variety of cognitive
functions including learning, memory and
navigation.
2. Ventral Tegmental Area (VTA): This
area is the first region involved in the
reward system (see Figure 4a and Figure
5). It receives input from the brainstem
and sends signals to the striatum and
nucleus accumbens (see below).
Figure 5: The reward pathway (black arrows) and the brain
regions that make up this system. Source:
https://commons.wikimedia.org/wiki/File:Dopamine_
pathways.svg
3. Striatum: The striatum plays a major role
in the reward system (see Figure 4b and
Figure 5). It regulates abilities and
feelings such as action-planning, motivation, and decision-making.
4. Nucleus Accumbens: This structure is responsible for feelings of pleasure, motivation and
learning through reinforcement. It also plays a role in the coordination of movement (see
Figure 4c and Figure 5).
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BACKGROUNDER: Page 4 of 4
GLOSSARY
Contralateral: Coordinated by structure on the opposite side of the body.
Endocrine System: Collection of glands throughout the body that regulate growth, metabolism and
mood.
Grey Matter: This is brain tissue consisting of cells without myelin, including the cell bodies of many
neurons (see Figure 1).
Hippocampal Formation: Region of the brain composed of many structures that are involved in
memory, navigation and attention.
Proprioception: Awareness of movement in space in relation to the body.
Reinforcement Learning: Learning by interacting with the environment and strengthening the
associated behaviour. It is like learning by ‘trial and error.’ If the interaction or behaviour creates a feeling
of reward, it is more likely to be performed again.
White Matter: This makes up the deep tissue of the brain. It consists of axons covered in white myelin
(see Figure 1). Myelin is a fatty tissue that insulates the axon and is important for signal transmission.
REFERENCES
Basic Brain Anatomy (Massachusetts Institute for Technology (MIT))
http://video.mit.edu/watch/basic-brain-anatomy-24559/ (Accessed August 13, 2015)
Reward pathway in the brain (Khan Academy on YouTube)
https://www.youtube.com/watch?v=YzCYuKX6zp8 (Accessed August 27, 2015)
Brain Anatomy and Functions (Nucleus Medical Media on YouTube)
https://www.youtube.com/watch?v=HVGlfcP3ATI (Accessed August 28, 2015)
Interactive Brain Anatomy (National Geographic)
http://science.nationalgeographic.com/science/health-and-human-body/human-body/brain-article/
(Accessed August 10, 2015)
The Brain – Anatomy and Function (WISC-Online)
https://www.wisc-online.com/learn/career-clusters/health-science/ota502/the-brain----anatomy-andfunction (Accessed August 10, 2015)
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