The Brain: What is going on in there?
Time: 45 minutes
Overview
At the end of this lesson, people will learn that neurons are the functional unit of the brain
and understand the hierarchical organization of the brain. Students will learn how neurons
convey, and interpret information. Students will also understand how neurons communicate
using electrical impulses and how chemical messengers also known as neurotransmitters activate
or inhibit neurons. Students will also be introduced to my current research on depression and
how it affects the population and activity of neurons in the brain.
Lesson Objectives
At the end of this lesson students will understand:
1. How the brain is organized, and that the neuron is the basic unit of the nervous system
2. How neurons communicate at their synapses
3. How chemical messengers, also known as neurotransmitters, can either excite or inhibit
neurons
4. The changes that current research has found to occur in people suffering from depression
Background Information
What is the brain?
The brain is the most important organ of the body. The brain controls how we think, what we
feel and how we act. The brain also controls body functions such as breathing, sleep, our heart
rate and body temperature. The field of neuroscience studies the brain and the nervous system.
The field of neuroscience studies how people control their behaviors, thoughts, and feelings, and
how these actions sometimes get out of control. The brain is responsible for processing a huge
amount of information in a remarkably efficient manner. Most of the activities that we do
without thinking such as driving a car involves a number of tasks that are processed by the brain.
How does the brain carry out multiple tasks at one time?
The brain splits larger tasks into smaller ones. Each part of the brain is divided into special parts
that analyze smaller information to create a bigger picture. For example, the back of the brain,
called the occipital lobe, specializes in seeing while the side portions of the brain called temporal
lobe is responsible for hearing. The downside to this type of organization is that if there is
anything wrong with one part of the brain, that part cannot perform the function it is designed to
do. For example, if there is something wrong with the occipital lobe of a person, that person may
loose his or her sight without any impairment in hearing or smell. This way of information
processing is referred to as parallel processing and has been used in the development of
computers.1
How does the brain communicate with the body?
The brain communicates with the body through the help of nerves. Nerves can be seen as the
extension of the brain and they carry information about the way we feel to the brain. For example
if you put your hands in cold water, the nerves in your hands carry the information from the
water (known as the stimulus) to your brain which then interprets this information to you as the
water being cold. There are millions of nerves in the body and these nerves communicate with
each other via chemicals known as neurotransmitters and these are secreted by nerves. There are
various types of neurotransmitters in the body and nerves are classified based on the types of
neurotransmitters that they secrete. For example, nerves that secrete dopamine, the
neurotransmitter that plays a major role in alertness and mood are called dopaminergic neurons.
How do drugs affect the brain?
The part of the brain that controls our emotions and motivations is referred to as the limbic
system. The limbic system controls how we respond to the world around us. The limbic system
uses memories, information about how your body is working, and current sensory input to
generate your emotional responses to current situations. The limbic system is composed of
various parts namely the amygdale which plays a major role in anger, and the hippocampus,
which plays a major role in learning and memory. Drugs can affect how neurotransmitters are
released and broken down in the limbic system, and thus affect the way we respond to our
environment. For example, cocaine blocks the reuptake of dopamine into the neuron, which
prolongs the effects of dopamine. There is a lot of ongoing research in the role of the limbic
system in depression and how anti depression drugs affect neurotransmitters in the human body.
Materials needed:
1. Projector
2. computers
3. pencils and paper
Procedure:
1. Have a brief 20 minute introduction of the brain with the students. Define what the
nervous system is and how the brain fits into the nervous system. It is important that
students realize that the neuron is the functional unit of the nervous system just as the cell
is the functional unit of the body. Then explain the roles of neurotransmitters in the
nervous system. Make mention of the types of neurotransmitters and how they either
excite or inhibit neurons in the nervous system.
2. Divide students into groups with no more than three to a computer. There are a series of
activities that involve critical thinking that students will perform. Select a leader for each
group and instruct the leader to write their response to the activities which would be
presented later on in class. This should take no more than 10 minutes. The activities are
designed to acquaint students with the brain, how it functions, and how neurotransmitters
work. Most of these activities are available at www.scicenceposse.org
3. Have each group report their results of the critical activity which should take no longer
than 10 minutes.
4. I will then present the results of my research to the class with videos showing the roles of
neurons in depression in the brain of rats.