Question 2. When the neurotransmitter glutamate is applied to the
neu ron, how does its activity change?
Glutamate stimulates the neuron and causes it to generate more
electrical impulses.
Question 3. How does the application of the two neurotransmitters,
glu tamate and GABA, change the activity of the neuron?
In this case, GABA is present in high enough concentrations to override
the effects of glutamate.
Question 4. Predict how the activity of the neuron would change if only
GABA was applied to the neuron.
If GABA can inhibit a neuron even when glutamate is added, GABA
by itself should inhibit the neuron’s activity.
Question 5. Do all neurotransmitters affect a neuron in the same way?
No, the neurotransmitters glutamate and GABA have opposite effects
on the neuron’s activity.
Question 6. How would the application of glutamate to a neuron change
the amount of neurotransmitter that is released from that neuron?
How would the application of GABA to a neuron change the amount
of neuro transmitter that is released from that neuron?
If glutamate is applied to a neuron, it causes the neuron to generate
more electrical impulses. This would increase the amount of
neurotransmitter that the neuron releases from its axon terminals.
55
Student Lesson 2
The Brain: Understanding Neurobiology Through the Study of Addiction
If GABA is applied to a neuron, it reduces the number of electrical
impulses generated by that neuron. The decreased activity in the
neuron would decrease the amount of neurotransmitter that the
neuron releases from its axon terminals.
3. Students can continue this activity using the simu lation on the
Web site of applying neurotransmitters to a neuron.
Go to the supplement’s Web site. Click on Lesson 2—
Neurons, Brain Chem istry, and Neurotransmission and then
select Neurotransmitter Actions.
Activity 4: One Neuron Signals Another
This activity is the most challenging one in the lesson. It requires students
to integrate what they learned in Activities 2 and 3. If students successfully
Content Standard A:
com plete this activity, they will have a good understanding of how neurons
Formulate and revise
com municate.
scientific explanations
1. Copy the chart from Master 2.8b, Neurons in Series, onto the board.
and models using logic
and evidence.
2. Now that students understand that neurotransmitters can either
Content Standard A:
stimu late or inhibit the generation of action potentials in a neuron,
Communicate and defend
they will continue to examine how one neuron signals another in
a scientific argument.
a series. Give each student a copy of Master 2.8. As a class, work
Content Standard C:
through Case A on the master to determine how the stimulatory
Cell functions are
and inhibitory neurotrans mitter effects alter dopamine release
from the last neuron in the series. Fill in the answers on the chart.
regulated.
You may wish to use an up or down arrow to indicate an increase or
decrease in the activity of the neuron or the amount of neurotransmitter
released from a neuron. Students may find it helpful to refer to their
work on Master 2.5.
Case A
The signal molecule that affects Neuron #1 in this case is inhibitory. It
reduces the chances that Neuron #1 will fire. Thus, it acts to decrease
the activity of Neuron #1. If Neuron #1 is less active, it releases less
neurotrans mitter. Neuron #1 produces glutamate, an excitatory
neurotransmitter. The decreased level of neurotransmitter released
from Neuron #1 leads to a decreased level of activity of Neuron #2.
If Neuron #2 is less active, it will release less dopamine.
56
Does the
amount
Does the
Does the
of neuro-
What is
Is the neuro-
amount of
signal
Does the
transmitter
the name of
transmitter
Does the
dopamine
molecule
activity of
released from the neuro-
released
activity of
released from
excite or
Neuron #1
Neuron #1
transmitter
from Neuron
Neuron #2
Neuron #2
inhibit
increase or
increase or
released from #1 excitatory
increase or
increase or
Case
Neuron #1?
decrease?
decrease?
Neuron #1?
or inhibitory?
decrease?
decrease?
A
inhibit
↓
↓
glutamate
excitatory
↓
↓
Tip from the field test: Students sometimes became confused by
the multiple neurotransmitters involved in each case. A common
misconception was the same neurotransmitter that acted to stimulate or
inhibit a neuron then passed through the neuron and was released from
the axon terminals at the other end. Remind students what they learned
in Activity 2 regarding the fate of a neurotransmitter after it binds to,
and then comes off, its receptor. The released neurotransmitter is either
degraded or taken back up into the axon terminal that released it.
For the purpose of this activity, the signal molecule is a
neurotransmitter. In Lesson 3, students will learn that drugs of
abuse can also act in a similar way to alter neurotransmission.
3. After the students have worked through the first example as a class,
ask them to work in their small groups to complete the chart for
Cases B–D. Students will determine how inhibitory and excitatory
inputs con tribute to the activity of a neuron that is part of a series.
As a student group finishes one of the cases (B–D), have a group
member come to the board and fill in the blanks for that problem.
When all of the groups are finished, ask the group that completed
each line on the board to explain its answers to the rest of the class.
If another group disagrees with the answer, have that group explain
its reasoning. As a class, resolve the discrepancies and reach a
consensus explanation. In this way, students practice critical
thinking and communication skills.
57
Student Lesson 2
The Brain: Understanding Neurobiology Through the Study of Addiction
Sample Answers for Master 2.8
Case A. The signaling molecule is inhibitory. Neuron #1 releases
gluta mate as its neurotransmitter. Neuron #2 releases dopamine
Listening to students
as its neuro transmitter.
explain their answers,
defend their reasoning,
The inhibitory signal molecule decreases the activity of Neuron #1. If
Neu ron #1 is less active, it releases less neurotransmitter. Neuron #1
and modify their responses
produces glutamate, an excitatory neurotransmitter. The decreased
after listening to other
amount of neuro transmitter released from Neuron #1 leads to a
students explain their logic
decreased level of activity of Neuron #2. If Neuron #2 is less active,
will help you assess
it will release less dopamine.
students’ understanding
of neurotransmission.
Case B. The signaling molecule is excitatory. Neuron #1 releases
gluta mate as its neurotransmitter. Neuron #2 releases dopamine
as its neuro transmitter.
The excitatory signal molecule increases the activity of Neuron #1. If
Neu ron #1 is more active, it releases more neurotransmitter. Neuron
#1 pro duces glutamate, an excitatory neurotransmitter. The increased
amount of neurotransmitter released from Neuron #1 leads to an
increase in the activity level of Neuron #2. If Neuron #2 is more
active, it will release more dopamine.
Case C. The signaling molecule is inhibitory. Neuron #1 releases
GABA as its neurotransmitter. Neuron #2 releases dopamine as
its neurotransmitter.
The inhibitory signal molecule decreases the activity of Neuron #1. If
Neuron #1 is less active, it releases less neurotransmitter. Neuron #1
pro duces GABA, an inhibitory neurotransmitter. The decreased amount
of neurotransmitter released from Neuron #1 leads to an increase in the
activity level of Neuron #2 (less GABA = less inhibition of Neuron #2).
If Neuron #2 is more active, it will release more dopamine.
Case D. The signaling molecule is excitatory. Neuron #1 releases
GABA as its neurotransmitter. Neuron #2 releases dopamine as
its neurotransmitter.
The excitatory signal molecule increases the activity of Neuron #1. If
Neu ron #1 is more active, it releases more neurotransmitter. Neuron #1
pro duces GABA, an inhibitory neurotransmitter. The increased amount
of neurotransmitter released from Neuron #1 leads to a decrease in
the activ ity level of Neuron #2 (more GABA = stronger inhibition of
Neuron #2). If Neuron #2 is less active, it will release less dopamine.
58
Does the
amount
Does the
Does the
of neuro-
What is
Is the neuro-
amount of
signal
Does the
transmitter
the name of
transmitter
Does the
dopamine
molecule
activity of
released from
the neuro-
released
activity of
released from
excite or
Neuron #1
Neuron #1
transmitter
from Neuron
Neuron #2
Neuron #2
inhibit
increase or
increase or
released from #1 excitatory
increase or
increase or
Case
Neuron #1?
decrease?
decrease?
Neuron #1?
or inhibitory?
decrease?
decrease?
A
inhibit
↓
↓
glutamate
excitatory
↓
↓
B
excite
↑
↑
glutamate
excitatory
↑
↑
C
inhibit
↓
↓
GABA
inhibitory
↑
↑
D
excite
↑
↑
GABA
inhibitory
↓
↓
4. Ask students to keep their completed worksheets, Masters 2.5 and 2.8.
Students will refer to these when they do activities in Lesson 3.
5. Students may continue to explore how signals from one neuron
influence the target neuron by doing the online activity Neurons
in Series.
To access the Neurons in Series activity, go to the supplement’s
Web site and click on Lesson 2— Neurons, Brain Chemistry, and Neurotransmission, and select the Neurons in Series tab.
59
Student Lesson 2
The Brain: Understanding Neurobiology Through the Study of Addiction
Lesson 2 Organizer: WEB VErSION
What the Teacher Does
Procedure
reference
Activity 1: Anatomy of a Neuron
Remind students of the PET images from Lesson 1. Ask students to
Page 50
think about what composes the differently colored areas.
Step 1
Display a transparency of Master 2.1. Explain to students that the
Page 50
neuron is the basic functional unit of the brain and nervous system.
Step 2
Point out the parts of the neuron and their function.
Display the top half of a transparency of Master 2.2. Point out that
Page 50
axon terminals of one neuron end near the dendrites of another
Step 3
neuron.
Reveal the bottom half of the Master 2.2 transparency. Inform
Page 51
students that the connection between the two neurons is called a
Step 4
synapse. Explain the terms presynaptic and postsynaptic.
Show the transparency of Master 1.7 from Lesson 1. Discuss the
Page 51
reward system in terms of the neurons that form the reward system.
Step 5
Activity 2: How Do Neurons Communicate?
Ask students to consider what purpose synapses serve.
Page 51
Step 1
Remind students that the brain is an organ that regulates many
Page 51
functions. Ask, “How do neurons fulfill these diverse functions?”
Step 2
Divide the class into groups of three. Give each group a copy of
Page 51
Master 2.3. Each group should work together to write descriptions of
Step 3
what is happening at each step.
Show the online animation How Neurotransmission Works
Page 52
to the class.
Step 4
Reconvene the student groups. Give each student a copy of
Page 53
Master 2.5. Ask students to work individually to revise their
Step 5
description of neurotransmission using the appropriate terminology.
After individuals have completed their descriptions, students can
discuss them with their team members.
60
What the Teacher Does
Procedure
reference
Discuss the descriptions of neurotransmission as a class and
Page 54
generate a consensus summary of neurotransmission.
Step 6
Remind students of the reward system and inform them that the
Page 54
neurons in the reward system use a neurotransmitter called dopamine.
Step 7
Activity 3: Do All Neurotransmitters Have the Same Effect?
Show a transparency of Master 2.6. Briefly explain that scientists
Page 54
study the activity of neurons by recording the electrical impulses
Step 1
that neurons generate when they are activated, or fire. Introduce
the term action potential.
Students return to their groups of three. Give each group a copy
Page 54
of Master 2.7. Ask students to work through the information and
Step 2
answer the questions.
Allow time for students to work through the simulation on the
Page 56
Web site. To access the simulation, select Lesson 2— Neurons, Brain
Step 3
Chemistry, and Neurotransmission from the activities menu and then
Neurotransmitter Actions.
Activity 4: One Neuron Signals Another
Copy the chart from Master 2.8b onto the board.
Page 56
Step 1
Give one copy of Master 2.8 to each student. As a class, work
Page 56
through Case A to determine how stimulatory and inhibitory
Step 2
neurotransmitter effects alter dopamine release. Write the answers
on the chart.
Have students work through Cases B–D in their teams. As teams
Pages 57–59
finish, ask for teams to volunteer to fill in the blanks for one of the
Step 3
cases on the chart on the board. Have teams explain the answers.
If teams disagree, discuss how they arrived at their answer. Work
through each case until there is consensus.
Have students keep their copies of Masters 2.5 and 2.8. Students Page 59
may then do the online activity Neurons in Series.
Steps 4, 5
= Involves using the Internet.
= Involves copying a master.
= Involves making a transparency.
61
Student Lesson 2
The Brain: Understanding Neurobiology Through the Study of Addiction
Lesson 2 Organizer: PrINT VErSION
What the Teacher Does
Procedure
reference
Activity 1: Anatomy of a Neuron
Remind students of the PET images from Lesson 1. Ask students to
Page 50
think about what composes the differently colored areas.
Step 1
Display a transparency of Master 2.1. Explain that the neuron is the
Page 50
basic functional unit of the brain and nervous system. Point out the
Step 2
parts of the neuron and their function.
Display the top half of a transparency of Master 2.2. Point out
Page 50
that axon terminals of one neuron end near the dendrites of
Step 3
another neuron.
Reveal the bottom half of the Master 2.2 transparency. Inform
Page 51
students that the connection between the two neurons is called a
Step 4
synapse. Explain the terms presynaptic and postsynaptic.
Show the transparency of Master 1.7 from Lesson 1. Discuss the
Page 51
reward system in terms of the neurons that form the reward system.
Step 5
Activity 2: How Do Neurons Communicate?
Ask students to consider what purpose synapses serve.
Page 51
Step 1
Remind students that the brain is an organ that regulates many
Page 51
functions. Ask, “How do neurons fulfil these diverse functions?”
Step 2
Divide the class into groups of three. Give each group a copy of
Page 51
Master 2.3. Each group should work together to write descriptions
Step 3
of what is happening at each step.
Display a transparency of Master 2.4. Read through the material
Page 52
with the students.
Step 4
Reconvene the student groups. Give each student a copy of
Page 53
Master 2.5. Ask students to work individually to revise their
Step 5
description of neurotransmission using the appropriate terminology.
After individuals have completed their descriptions, students can
discuss them with their team members.
62
What the Teacher Does
Procedure
reference
Discuss the descriptions of neurotransmission as a class and
Page 54
generate a consen