Chapter 14: Biological Rhythms, Sleep, and Dreaming Flashcards
1
Q
What is an example of a short rhythm?
A
Pacemaker cells in the heart
2
Q
What is an example of a long rhythm?
A
Seasonal cycles (circannual rhythms)
3
Q
Circadian Rhythms
A
A pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period.
4
Q
What is NOT TRUE about circadian rhythms?
A
The light/dark cycle can influence them.
5
Q
What is true about a TRUE circadian rhythm?
A
It is independent and cannot be influenced.
6
Q
Free Running
A
An animal maintaining a circadian rhythm without external cues.
7
Q
What are example of external cues in free running?
A
- Outside noises
- Temperature
- Barometric Pressure
8
Q
Phase Shift
A
A shift in activity of a biological rhythm, provided by a synchronizing environmental stimulus.
9
Q
Synchronizing Stimulus
A
A signal that can cause people to temporarily align their movements/brain activity.
10
Q
Entertainment
A
The process of synchronizing a biological rhythm to an environmental stimulus.
11
Q
Zeitgeber
A
The external cue that an animal uses to synchronize its activity with the environment.
12
Q
What is the Zeitgeber also known as?
A
The “time giver”
13
Q
What is an example of a zeitgeber?
A
Light
14
Q
What do circadian rhythms provide in connection to animal behavior?
A
Temporal organization
15
Q
Suprachiasmatic Nucleus (SCN)
A
A small region in the hypothalamus above the optic chiasm that sets the circadian rhythm.
16
Q
Explain the hamster experiment in relation to the SCN.
A
- Hamsters that had damage to the SCN were placed in constant conditions, causing their natural rhythms to be completely disrupted.
- The hamsters received transplants of SCN tissue from fetal hamsters with the same tau mutation.
- After a week, the transplanted hamsters started showing a new rhythm. However, this rhythm was shorter than the usual 24 hour cycle, which matches those of the donor hamsters SCN.
17
Q
What happened to the hamsters that had the tau mutation in a gene?
A
They usually had short circadian rhythms.
18
Q
What provides evidence for the SCN to be an endogenous rhythm maker?
A
The hamster experiment
19
Q
What do most vertebrates have outside their eyes?
A
Photoreceptors that are associated with circadian rhythms.
20
Q
What is an example of photoreceptors being outside the eye?
A
The pineal gland in amphibians is sensitive to light.
21
Q
What type of cells do mammals have in their eyes?
A
Cells that provide light/dark information to the SCN
22
Q
What do the special ganglion cells do?
A
Form the retinohypothalamic pathway due to the presence of melanopsin.
23
Q
Melanopsin
A
A photopigment found in some retinal ganglion cells that project to the suprachiasmatic nucleus.
24
Q
Retinohypothalamic Pathway
A
The projection of retinal ganglion cells to the suprachiasmatic nuclei.
25
Explain how the SCN has an endogenous rhythm in relation to fruit flies.
- Fruit flies display diurnal circadian rhythms in activity.
- Flies with a mutation that disabled the gene called per were arrhythmic when transferred to a constant dim light.
= internal clock is not running
26
What is the importance of the fruit fly experiment?
It was discovered that mammals have mechanisms that underly SCN circadian rhythms due to similar genes in fruit flies.
27
What do SCN related genes in flies and mice provide?
A molecular clock, regulating a 24-hour expression based off of protein products working together.
28
What two proteins do cells in the SCN make?
Clock and Cycle
29
Explain the process of genes in the SCN.
1. Two proteins, Clock and Cycle, bind together to form dimer.
2. The Clock/Cycle dimer binds to the DNA, enhancing the transcription of the genes for Per and Cry.
3. Per and Cry bind together as a complex that inhibits the activity of the Clock/Cycle dimer.
= Slows production of Per and Cry genes, and production of Per and Cry proteins.
4. The Per/Cry proteins eventually break down/modified so they no longer inhibit the Clock/Cycle, allowing the process to start again. (process takes 24)
5. Retinal ganglion cells detect light with melanopsin, and their axons in the retinohypothalamic tract release glutamate onto neurons in the SCN. The glutamate stimulation leads to increased transcription of the Per gene
= Synchronized molecular clock to the day/night schedule.
30
What can mutations in the SCN genes cause?
Issues to circadian rhythms
31
Dimer
A complex of two proteins that have bound together.
32
What happens when there is a mutation to the Clock gene?
The mouse is able to maintain rhythm until it is in dim light. After 27 hours it completely loses rhythm but an ultradian rhythm remains.
33
What causes some people to be night owls/early birds?
Different alleles (version) of Clock or Per gene
34
What can we take away from time zones?
Light still entrains humans
35
Ultradian Rhythms
Frequency is greater than once/day
36
What is an example of ultradian rhythms?
The basic rest activity cycle in humans
- about 90 minutes
37
Infradian Rhythms
Frequency is less than once/day
38
What is an example of infradian rhythms?
The menstrual cycle (humans and apes) or estrous cycle (other mammals)
39
Circannual Rhythms
Frequency is about a year
40
What can affect circannual rhythms?
Light
41
What are circannual rhythms not dependent on?
SCN
42
What is the most prominent circadian rhythm?
The sleep/wake cycle
43
How long does the free running sleep/wake rhythm last?
About 25 hours in humans.
44
What 3 tests can help investigate sleep in humans?
- EEG
- EMG
- EOG
45
EEG
The recording and study of gross electrical activity of the brain recorded from large electrodes placed on the scalp.
46
What does an EEG indicate?
An "awake" brain as musculature is relaxed/limp
47
EMG
The electrical reading of muscle activity. -
48
EOG
The electrical recording of eye movements.
49
What are the 5 stages of sleep?
Awake
1. NREM
2. Basic alpha rhythm
3. Slow wave sleep (SWS)
4. REM
50
Rapid-Eye Movement Sleep (REM)
A stage of sleep characterized by small amplitude, fast EEG waves, no postural tension, and rapid eye movements.
51
What is REM sleep also known as?
Paradoxical sleep
52
Non-REM (NREM) Sleep
Sleep without rapid eye movements.
53
What is NREM sleep divided into?
Stages 1, 2 and 3 of sleep
54
Awake Stage
EEG is out of its usual patten
- 15 to 20 Hz and low amplitude
55
Stage 1: NREM
- 8 to 12 Hz activity (alpha rhythm)
- Vertex spikes (sharp spikes in EEG)
- "Hypnic Jerks"
56
"Hypnic" Jerks
People can experience the sensation of falling and jerk into wakefulness
57
Stage 2: Basic Alpha Rhythm
- Sleep spindles
- K complexes
58
Sleep Spindles
12-14 Hz bursts that occur periodically
59
K Complexes
Sharp negative EEG potentials
60
What happens when people are awoken in stages 1 or 2 of NREM?
They will deny having been asleep.
61
Stage 3: Slow Wave Sleep (SWS)
- Delta waves
- Large amplitude and very slow waves (1 Hz)
62
Delta Waves
Widespread synchronized activity across the cortex
63
Stage 4: REM Sleep
Despite deep muscle relaxation, the EEG activity in REM sleep resembles that of waking.
- Eyes move rapidly
- Breathing and heart rate become uneven
64
What stage do people usually experience vivid dreams?
Stage 4: REM
65
What is the relationship between REM and stage 3 sleep?
REM lengthens throughout the night as stage 3 decreases.
66
How long are the cycles during sleep?
90-110 minutes
67
What do the sleep cycles refelct?
Basic rest activity cyle
68
When do dreams occur?
REM and NREM sleep
69
REM Dreams
Vivid, highly visual, and often built around stories where the dreamer is present.
70
Non-REM Dreams
More about thoughts/thinking.
71
Night Terrors
Sudden arousal from stage 3 sleep with intense fear and activation of autonomic system
- feel a crushing on your chest
72
Who are night terrors the most common among?
Children
73
Night terrors are not the same as....
nightmares
74
What are the 2 pieces of evidence to support the evolution of sleep?
1. Even vertebrates show NREM when inactive.
2. REM is only present in birds and mammals
75
What happens to your sleep patterns as you age?
- Less sleep is needed
- Typical sleep pattern changes (more awakenings at night)
76
What do infant mammals show?
A higher % of REM sleep
77
What age has the shortest sleep cycles?
Infant
78
Explain how sleep deprivation affected rats.
In the rats that sustained sleep deprivation they faced..
-increased metabolic rate
-weight loss
-death after an average of 19 days.
79
What caused the death in rats who experienced sleep deprivation?
A bacterial infection that is usually fought off by the immune system
80
What is sleep important for?
Immune function
81
Fatal Familial Insomnia
A genetic defect where an individual stops sleeping mid age
-dies within 7-24 months.
82
Does loss of sleep cause people to go crazy?
83
What causes occasional hallucinations?
Prolonged sleep deprivation of greater than 8 days.
84
What are the most common changes in sleep deprivation?
- Increased irritability
- Difficulty concentrating
- Disorientation
85
Even with moderate sleep deprivation (4-6 hours), what can an individual experience?
A decrease in attention and reaction times
86
What do you never completely recover from?
Sleep Loss
87
What are the 4 functions of sleep?
1. Energy Conservation
2. Niche Adaption
3. Body Restoration
4. Memory Consolidation
88
Energy Conservation
- Reduced body temperature, slower respiration, and slower heart rate
= Reduced metabolic activity
89
When does energy conservation occur in animals?
When an animal would not be good at getting food (conserve energy)
90
Plant eaters sleep more when...
Their body size is smaller
91
What is the relationship between meat eaters and sleep?
They sleep a lot no matter their body size.
92
Niche Adaption
Sleep enforces this adaption to a particular ecological niche
93
Ecological Niche
Unique assortment of environmental opportunities and challenges to which each organism is adapted.
94
Body Restoration
Sleep helps rebuild/restore body materials and functions.
95
What does prolonged deprivation of sleep lead to?
A weakened immune system
96
What is a factor of working night shifts?
People who work at night and sleep during the day are more likely to develop cancer.
97
What does body restoration not refer to?
Simple wear and tear
(exercise does not cause people to sleep longer)
98
Memory Consolidation
Sleep PROMOTES memory consolidation
99
What are researchers still debating?
The relationship between REM sleep and memory
100
There is a strong relationship between memories and...
NREM sleep
101
What can improve one's performance on a task?
Thinking about a task during sleep
102
What are the 4 neural systems?
1. Forebrain System
2. Brainstem System
3. Pontine System
4. Hypothalamic System
103
Forebrain System
Can display slow-wave sleep (SWS) by itself
104
What happens when the basal forebrain is stimulated?
It leads to sleepiness
105
Explain the movement of the basal forebrain neurons.
- The basal forebrain neurons become active at the onset of sleep.
- The neurons project to the tuberomammillary nucleus (hypothalamus)
- The neurons release GABA there
106
Brainstem System
Activates forebrain into wakefulness
- The cells are projected to a variety of structures which promotes wakefulness
107
Reticular Formation
Collection of cells throughout the brainstem
108
Pontine System
Triggers REM sleep
109
Explain how the Pontine system works.
- There are a small group of cells in pons that triggers REM sleep.
- Some cells project to motoneurons and strongly inhibit them
= Muscles flaccid (not just relaxed)
110
Hypothalamic System
Controls other three brain systems to determine sleep/wake
111
How was the hypothalamic system discovered?
Through narcoleptic dogs
112
Narcolepsy
A person/animal has sudden, intensive bouts of sleep during the day.
113
When do people with narcolepsy typically enter REM?
Immediately after falling asleep rather than NREM at night.
114
How long does sleep usually last for people with narcolepsy?
5-30 minutes
115
What is the cause for narcolepsy in dogs?
A mutant gene in a recetor for hypocretin (neuropeptide)
116
Hypocretin
Hypothalamic peptides involved in switching between sleep states, in narcolepsy, and in the control of appetite.
117
What causes mice to suffer from narcolepsy?
The hypocretin gene is knocked out.
118
What causes humans to suffer from narcolepsy?
There is a profound loss of hypocretin neurons (in the hypothalamus)
119
Hypocretin Neurons
Project to the basal forebrain, reticular formation, and locus Corneluis
= control sleep/wakefulness.
120
Where are hypocretin neurons also found (not main area)?
The tuberomammillary nucleus in the hypothalamus
121
What do narcoleptics also suffer from?
Cataplexy
122
Cataplexy
Sudden loss of muscle tone without loss of consciousness
123
What can cataplexy in dogs be caused by?
Strong emotions (positive or negative)
124
How can narcolepsy be treated?
Various medications
125
What is the newest narcoleptic medication?
Modafinil
126
What is the most common symptom in narcolepsy?
Sleep Paralysis
127
What could be a possible cause for sleep paralysis?
Continued activity in the pontine system that inhibits motoneurons
128
What are the 2 most common sleep disorders in children?
- Night terrors
- Enuresis
129
Sleep Enuresis
Bed wetting
130
When stage of sleep does sleep enuresis occur?
Stage 3: SWS
131
How can sleep enuresis be treated?
-Drugs that decrease stage 3
- Antidiuretic (controls water balance)
132
Somnambulism
Sleepwalking
133
Who is somnambulism most common in?
Children but it can persist into adulthood
134
When does somnambulism occur?
Stage 3: SWS
135
What does somnambulism not mean?
They are acting out a dream
136
REM Behavior Disorder
One appears to be acting out a dream in their sleep
137
What is REM Behavior Disorder characterized by?
Organized behavior
138
What age does REM Behavior Disorder usually begin at?
50
139
What gender is REM Behavior Disorder most common in?
Males
140
What disorders is REM Behavior Disorder usually followed by?
Parkinson's or Dementia
141
Insomnia
Difficulty falling asleep/staying asleep as one would like.
142
What are the two kinds of insomnia?
1. Sleep onset insomnia
2. Sleep maintenance insomnia
143
Sleep Onset Insomnia
Difficulty in falling asleep.
144
What is sleep onset insomnia often caused by?
Situational factors
145
Sleep Maintenance Insomnia
Difficulty in staying asleep.
146
What is sleep maintenance insomnia usually caused by?
Sleep apnea
147
What 3 drugs are used to treat insomnia?
1. Barbiturates (highly addictive)
2. Benzodiazepines (recent)
3. Benzo mimics (amien, sonata, lunesta)
148
What is the BEST treatment for insomnia?
Visit a sleep clinic/work with a sleep disorder expert to practice good "sleep hygine"
149
Sleep Hygiene
Habits, such as avoiding caffeine shortly before bedtime, that promote healthy sleep.
150
What are the problems with using drugs to treat insomnia?
- Lose effectiveness overtime
-Do not produce normal sleep
- Drowsiness during the day
151
Sleep Apnea
Respiration becomes unreliable, and a person may stop breathing for a minute.
152
What is the most concerning problem of sleep apnea?
It may kill neurons and lead to a variety of cardiovascular problems.
153
What is the solution to sleep apnea?
CPAP machine to maintain air pressure in airways to prevent collapse.
154
Sudden Infant Death Syndrome (SIDS)
The sudden, unexpected death of an apparently healthy human infant who simply stops breathing, usually during sleep.
155
What is a possible cause for SIDS?
Abnormalities in the serotonin system (brainstem) that regulate respiration
