Brain, Hormones and Metabolism (HAP30806) 2019-2020
Brain, Hormones
And Metabolism
Tutorial SW1
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,Brain, Hormones and Metabolism (HAP30806) 2019-2020
Theme 2 - Tutorial SW1: Sleep
Introduction:
In this tutorial class specific aspects of Sleep will be addressed in more detail. Before being able to answer
the questions below, please study Chapter 14 from the book Behavioral Neuroscience, 8th edition, 2017
and the recording of classroom lecture 3. Make the questions for the tutorial class when studying
Breedlove and upload your answers in Brightspace before Friday March 20, 10.00 am. Your answers to
the questions will be extensively discussed online.
Questions:
1. During sleep the activity of the brain undergoes dramatic changes.
a. Explain the function of these brain activity changes during sleep. What proof do we have for
this?
The brain reorganizes in this period to be able to maintain cognitive performance and memorize your
experiences from the day.
b. In line with (a) discuss what the consequences are of sleep deprivation in relation to physical
exercise and mental activity.
Mental activity will decrease and cognitive performance and forming memories will decrease. Sleep
deprivation results in a decrease in the production of glycogen and carbohydrates, leading to a lesser
physical performance.
2. Sleep is a highly preserved behaviour throughout the animal kingdom. The amount of sleep an
animal needs depends on its way of living. Try to answer the following questions:
a. Can we or other mammals do without REM sleep?
During REM sleep, active dreaming takes place and your some of your muscles paralyse, heart rate,
blood pressure and body temperature are variable during REM sleep. Humans and all mammals
need REM sleep. Only insects and fish don’t have REM sleep.
b. Are there differences in the amount of REM sleep we need during growing up? Explain your
answers.
Yes, REM sleep decreases with age. REM sleep is associated with brain development and as this is
mostly needed in early ages, REM sleep occurs more/longer when you are younger.
3. Name as much factors as you can recall that are involved in the initiation of REM sleep, and
how do these factors interact with each other in the initiation of this process. Explain your
answer.
Acetylcholine is associated with REM sleep and the initiation is starts in the acetylcholine neurons
located in the pons (peribrachial area).
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, Brain, Hormones and Metabolism (HAP30806) 2019-2020
4. The SCN also provides the primary control over the timing of sleep. Lesions of the SCN can
interfere with the day-night rhythm of an animal.
a. Do lesions of the SCN interfere with the amount of sleep an animal normally gets? Explain your
answer.
Yes, lesions in the pons for example may cause alternation in acetylcholine release and this
consecutively affects the amount of sleep.
b. The SCN receives its information from photoreceptors in the retina. Discuss what would happen
to the day-night rhythm in blind people. Take into account while answering this question the
cause of blindness.
Light is the primary factor to reset your internal circadian clock, which regulates the day and night cycle.
In blind people, light can’t or hardly reaches the SCN, so the internal clock is not synchronized, which
alters their circadian clock, they will have a body clock that is a bit longer than 24 hours. Their rhythm
moves forward every single day. If blind people do have some perception of light, the internal clock can
be synchronized.
5. Sleep disorders can have different causes. One sleep disorder, narcolepsy is found both in
animals and humans.
a. What are the major characteristics of narcolepsy?
Narcolepsy is a sleeping disorder in which people can fall asleep during the day and can have a
continued feeling of sleepiness. They have uncontrollable periods of sleepiness.
b. Narcolepsy is considered to be a REM sleep disorder. Do you agree with this assumption, and
if yes/no, why? Please explain your answer.
No, as there is no abnormal REM sleep generation in narcolepsy.
c. Is narcolepsy always caused by a genetic disorder? What sort of disorder(s) are involved and
how can one find out the cause of the disorder (you may explain your answer using
experimental animal models).
Narcolepsy is thought to be caused by a lack of a brain chemical called hypocretin, which regulates
sleep cycles. The deficiency of this chemical is considered to be the result of an immune disorder (the
immune system, antibodies, attacks parts of the brain where hypocretin is produced). This can be due
to an inherited genetic disorder, hormonal changes, psychological stress, change in sleep patterns or
an infection. Also, brain tumours, head injury, MS or encephalitis can cause narcolepsy. The cause of
the disorder can be found by checking for physical injury, by doing a ct scan. Blood tests can be
performed and the presence of certain antibodies and hormones can be checked.
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