1
Q
What is REM sleep?
A
- Associated with dreaming
- EEG activity looks as though you are awake
- Apart from physical twitching and eye darting, muscles are totally inactive
- Cerebral blood flow and oxygen consumption increase
• At the end of a REM cycle, people may wake up and reposition and fall back to sleep
2
Q
What is slow-wave, deep non-REM sleep?
A
Sleep stages 3 and 4
- Associated with large amplitude low frequency oscillations of brain activity as measured with EEG
- This pattern of neural activity reflects bursts of action potentials that are synchronized across large collections of neurons
- Oscillatory activity is the most pronounced
3
Q
What is beta activity?
A
- Typical of an aroused state
- Reflects dyssynchronous neural activity (high frequency, low amplitude oscillations)
4
Q
What is alpha activity?
A
- Typical of an awake person in a state of relaxation
- Desynchronized neural activity
5
Q
What is theta activity?
A
Appears intermittently when people are drowsy, and is prominent during early stages of slow-wave sleep
6
Q
What is delta activity?
A
- Occurs during deepest stages of slow-wave sleep
- Reflects synchronized low frequency, large amplitude brain activity
- After stage 4, you go back into REM
7
Q
What is the glymphatic system?
A
Waste clearance pathway of the brain; it removes excess proteins and other metabolic waste from the interstitial space in the brain (use of CSF as a filter)
- The clearance of proteins and waste products from the brain is almost nonexistent during wakefulness but really high during sleep
- In contrast, the waste clearance system in the rest of the body, the lymphatic system, is always active
8
Q
What are circadian rhythms?
A
• The daily change in behaviour and physiological processes that follows a cycle of approximately 24 hours is known as a circadian rhythm
• They are controlled by internal biological clocks
- Regular variations in light levels keeps the clock adjusted to 24 hours
9
Q
What is the suprachiasmic nucleus (SCN)?
A
- Located in hypothalamus, it regulates sleep cycles – it receives a direct input from the retina
- SCN lesions alter the length and timing of sleep-wake cycles, but they do not change the total amount of time that animals spend asleep
- Every cell within the SCN has its own clock
10
Q
What is advanced sleep phase syndrome?
A
A mutation of a gene called per2 (period 2) causes a 4-hour advance in the biological clock – a string desire to fall asleep at 7pm and wake up at 4am
- Sets the clock wrong, better for them to just get used to it because their clock will not change
11
Q
What is delayed sleep syndrome?
A
a mutation of a gene called per3 causes a 4-hour delay in rhythms of sleep and temperature cycles – a strong desire to fall asleep at 2am and wake up at 11am
12
Q
What is caffeine?
A
an adenosine receptor antagonist
13
Q
What does norepinephrine activity correlate with?
A
focus and attention
14
Q
What does serotonin (5-HT) neuron activity correlate with?
A
Positively correlates with cortical arousal, and drugs that increase serotonin signalling tend to suppress aspects of REM sleep (without affecting memory)
15
Q
What are neuropeptides?
A
they are released in many areas of the brain but are only made in small groups of neurons in the hypothalamus
16
Q
What are histamine receptor blockers (antihistamines)?
A
Often cause drowsiness, since they could cross the blood-brain barrier
• Histamine release can cause allergies
17
Q
What do neurons in the ventral lateral preoptic area (vlPOA) of the hypothalamus do?
A
They promote sleep
- Electrical stimulation causes drowsiness and sometimes immediate sleep
- Lesions suppress sleep and cause insomnia
- They inhibit wake-promoting neurons such as histamine, serotonin, and norepinephrine neurons
18
Q
What is the function of the ventral lateral preoptic area (vlPOA)?
A
It receives inhibitory inputs from the same regions it inhibits ( inhibited by histamine, serotonin, and norepinephrine)
- This kind of reciprocal inhibition characterizes a flip-flop circuit; both regions cannot be active at the same time and the switch from one state to another is fast
- Either the sleep neurons are active and inhibit the wakefulness neurons, or the wakefulness neurons are active and inhibit the sleep neurons.
19
Q
What is orexin (hypocretin)?
A
A peptide produced by the neurons in the hypothalamus that promotes wakefulness
- Absence or degeneration = narcolepsy
20
Q
What is narcolepsy?
A
• Sleep disorder characterized by periods of excessive daytime sleepiness and irresistible urges to sleep as well as other symptoms
- It’s a hereditary autoimmune disorder
- For most with narcoleptics, this disease is caused by the death (degeneration) of orexin neurons in the hypothalamus
21
Q
What is cataplexy?
A
complete paralysis that occurs during waking, typically precipitated by strong emotional reactions or sudden physical effort (ex: laughter, anger, excitability)
22
Q
What is sleep paralysis?
A
REM-associated paralysis occurring just before a person falls asleep
- Often accompanied by vivid dream-like hallucinations
- Due to the lack of orexin neurons and the lack of promoting the arousal system, sometimes the REM circuits become activated while the circuit is awake, triggered by emotional reactions in the amygdala
23
Q
What is insomnia?
A
• Difficulty falling asleep after going to bed or after awakening during the night
24
Q
What is fatal familial insomnia and sporadic fatal insomnia?
A
• A very rare disease that involve progressively worsening insomnia, which leads to hallucinations, delirium, and confusional states
- Typically inherited but can also develop spontaneously
- Has no known cure and he average survival span after the onset of symptoms is 18 months
• Going under anesthesia gives the benefits of sleep, so this is what some people try
- However, it is risky, as too much anesthesia can be fatal
25
What are disorders associated with non-REM sleep (non-REM parasomnias)?
• The brain seems to get caught in between a sleeping and waking state; many people are unaware that they exhibit this behaviour
- Sleepwalking, sleep-talking, etc
- Some of these tend to be more prevalent in children
- Episodes can last seconds to minutes or longer
- These states can be caused by certain medications or medical conditions
26
What are sleep terrors?
Characterized by overwhelming feelings of terror upon waking
- May include panic and screaming and bodily harm caused by rash actions
- People sometimes have no recollection of these events
- Prevalent in people diagnosed with post-traumatic stress disorder
27
What is REM sleep behaviour disorder?
• Neurological disorder in which the person does not become paralyzed during REM sleep and thus acts out dreams
• Happens in the SECOND half of the night
- It is often associated with better-known neurodegenerative disorders such as Parkinson’s disease
- Absence of GABA signalling to regulate motor commands
28
What is sexual dimorphism?
• The condition where the two sexes of the same species exhibit different characteristics beyond the differences in sexual organs
- These differences may be subtle or exaggerated and can include differences in size, weight, color, behaviour, and cognition
- They include secondary sex characteristics (features that occur during puberty)
29
What is sexual dimorphic behaviour?
behaviours that have different forms or occur with different probabilities or under different circumstances across males and females
- In mammalian species, the most striking category of sexual dimorphic behaviours are their reproductive behaviours
- The brain gives rise to sexual dimorphic behaviours because it is a sexually dimorphic organ
30
What are the sex chromosomes?
X and Y
| - They typically determine an organism’s sex
31
What are gonads?
Ovaries or testes
- they make reproductive cells called gametes, which are either ova (egg cells) or sperm
- Split to make gametes
32
What are undifferentiated gonads?
Embryonic precursor of ovaries/testes
33
What is the Mullerian system?
Embryonic precursors of female internal sex organs
34
What is the Wolffian system?
Embryonic precursors of male internal sex organs
35
What is the SRY gene?
• One specific gene on the y chromosome that encodes a protein that causes the undifferentiated fetal gonads to develop into testes
- This gene overpowers xx-ovary instructions, so XXY individuals develop testes
36
What is the defeminizing effect?
Effect of anti-Mullerian hormone early in development, which prevents development of the internal anatomy typical of females
37
What is the masculinizing effect?
Effect of androgen hormones early in development, which promotes anatomical characteristics typical of males
38
What are androgens?
Male sex steroid hormones
39
What is terstosterone?
Principle mammalian androgen
40
What is dihydrotestosterone?
Made from testosterone, it triggers development of male external sex organs
41
What is Turner syndrome?
When you only have one sex chromosome (X0)
| - Associated with abnormalities on account of missing a full chromosome
42
What is swyer syndrome?
When you are XY but have a bad SRY gene
- In both cases, gonads don’t develop
- Internal and external female sex organs will develop normally, since there are no testicular hormones, but the person will be sterile since they lack ovaries
- Without gonads, puberty will have to be artificially induced (with the hormone estradiol)
43
What will insufficient anti-Mullerian hormone signalling cause?
It will cause insufficient defeminization: both male and female internal sex organs will develop and get tangled together; there is often functional external male genitalia
44
What is androgen insensitivity syndrome?
Results in partial or no masculinization
- In severe cases, no internal sex organs develop, yet the person will have external female genitalia and typically identify as a heterosexual woman who is sterile and has a short vagina
45
What happens if the production of anti-Mullerian hormone is insufficient or the receptors for it are lacking in either number or function?
- Mullerian system will not wither away and it will develop internal female organs
- Wolffian system also develops and creates internal male organs
- External male genitalia will also develop
46
What happens if there is insufficient testosterone signalling?
- Male internal and external organs will not be created
| - The Mullerian system will also wither away if it’s defeminized
47
What is behavioural defeminization?
Refers to organizational effects of androgens on the brain that prevent animals from displaying female-typical behaviours in adulthood
48
What is behavioural masculinization?
Refers to organizational effects of androgens on the brain that enables animals to engage in male-typical behaviours in adulthood
49
What is puberty triggered by?
the releases of signalling molecules in the hypothalamus
50
What is the peptide that leads to the triggering cascade of puberty?
Kisspeptin (relates to sexual maturation)
| - Neighbouring neurons release GnRH
51
What is GnRH?
Causes pituitary cells to put two gonadotropic hormones in the blood
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone
52
What is the function of gonadotropic hormones?
They have a stimulating effect on cells of gonads
53
What is estrogen?
Class of sex hormones typically released by the ovaries that cause maturation of the physical features characteristic of females, such as the growth of breast tissue and female genitalia
54
What is estradiol?
principal estrogen of many mammals, including humans
55
What is the menstrual cycle?
- Female reproductive cycle of most primates, including humans
- Characterized by menstruation (if pregnancy doesn't occur)
- Sexual arousal is somewhat influenced by ovarian hormones, but ability to mate is not
- Animals with a menstrual cycle exhibit sexual activity throughout the cycle
56
What is the estrous cycle?
- Female reproductive cycle of mammals other than most primates
- Females that have estrous cycles do not menstruate; they absorb their endometrium
- Only typically sexually active during estrous phase of cycle (referred to as being in 'heat')
57
What is the lordosis response?
When rodents stick their genitals out for a mate
58
What is congenital adrenal hyperplasia (CAH)?
in females, excess androgen signalling can cause some degree of masculinization of either the body or brain or both
59
What is the function of the medial amygdala?
gets fairly unprocessed inputs from sensory systems
60
What is the ventromedial nucleus of hypothalamus (VMH)?
Large nucleus in the hypothalamus that plays essential role in female sexual behaviour – in rodents:
- Electrical stimulation of VMH facilitates female sexual behaviour
- Injections of estradiol and progesterone directly into VMH also stimulates sexual behaviour, even in females whose ovaries have been removed
- Females with lesions of VMH will not display lordosis, even if she is treated with estradiol and progesterone
61
What is the medial preoptic area (mPOA)?
Nucleus in the anterior hypothalamus that plays essential role in male sexual behaviour
- Electrical stimulation of mPOA in rodents elicits male copulatory behaviour
- Lesioning the mPOA of female rats doesn’t affect their sexual behaviour, but it does cause them to ignore their offspring
- This is not true in males, it only changes their reproductive behaviour
62
What is the SDN?
sexually dimorphic nucleus of the preoptic area (much larger in males than in females)
63
What are the two peptides in the brain related to pair bonds?
vasopressin and oxytocin
| - released during sex, childbirth, and breastfeeding
64
What are pheromones?
Chemical released by one animal that affects behaviour or physiology of another animal; usually smelled or tasted
- Detection of normal odours occurs in the olfactory system, but the effect of pheromones is mediated by the VNO
65
What is the vomeronasal organ (VNO)?
A small collection of sensory receptor cells that detect the presence of certain molecules in the nasal cavity
- Mediates effects of many pheromones in rodents, which often influence reproductive cycles and sexual behaviour
- Humans do not seem to have a functional VNO, although some pheromone effects have been demonstrated
- VNO is typically activated when a rodent investigates the mouth or anogenital region or another rodent
- The VNO system connects to the accessory olfactory bulb via the vomeronasal nerve
66
What is the lee-boot effect?
when female mice are housed together (without any male urine present), their estrous cycles slow down and eventually stop
67
What is the Whitten effect?
Synchronization of menstrual or estrous cycles of group of females, which occurs only in presence of pheromones in male’s urine
- Typically happens after the lee-boot effect
68
What is the Vandenburgh effect?
earlier onset of puberty seen in female animals that are housed with males; caused by pheromone in male’s urine
69
What is the Bruce effect?
The tendency for female rodents to terminate their pregnancies following exposure to the scent of an unfamiliar male
- Males tend to get violent towards other pups (not their own), so females terminate pregnancies, so their offspring doesn’t get killed by the unfamiliar male
70
What is volitional facial paresis?
Condition where people are unable to voluntarily control their facial muscles, but they can express genuine emotion with the same muscles
- Damage in facial region of primary motor cortex
- You can naturally show emotion, but not when told to
71
What is emotional facial paresis?
Opposite of volitional
- Can voluntarily show emotion, but not naturally
- Damage around insular cortex and parts of the thalamus
72
What is the theory of emotion?
1. Perception of the emotion-eliciting event (ex: see a bear)
2. Subjective feelings of emotion (ex: fear)
3. Behavioural and physiological responses (ex: trembling, sweating, and running away)
73
What is the James-Lange theory?
1. Perception of emotion-eliciting event (see a bear)
2. Appropriate set of behavioural and physiological responses are triggered (clench fists, run away, sweating, trembling, increased heart rate)
3. The brain receives feedback from these changes in the peripheral nervous system which, in turn, produces the subjective feelings of emotion
- The brain is interpreting the changes that it observes through the body, not the actual source of fear (the bear)
74
What is the function of the central nucleus of the amygdala?
Regulates emotional responses, particularly fear responses
- It sends information to various brain structures which control different emotional responses
- Lesions of the central nucleus reduce/eliminate fear responses
- Stimulation causes fear, anxiety, or agitation
75
What happens to patients with damage to primary visual cortex or visual association cortex?
They may have no conscious awareness of looking at a person’s face, yet they still show amygdala activity in response to viewing faces and often mimic the presented facial reaction
76
What happens to patients with bilateral amygdala damage?
When shown photos of faces, she doesn’t look at the eyes
- They can recognize the emotion if she is trained to look at the eyes, but she doesn’t do it spontaneously; she has to be reminded every time
77
What is the simulation theory?
When we see someone’s facial expressions, in order for us to understand what emotion it is, we imagine ourselves making facial expressions
78
What are mirror neurons?
Neurons that are activated similarly when an animal performs a particular behaviour or when it sees another animal performing that behaviour
- They will fire the same action potentials
- They are thought to be involved in mimicry and empathy
79
What is the lateral nucleus in the amygdala?
Receives both raw and processed information
| - Projects to many places, most prominently the central nucleus
80
What is extinction learning?
Involves forming a new memory (CS --> nothing) in addition to weakening the old memory (CS --> US)
- it reduces the likelihood the animal will respond to the CS with a CR, but it will not go to 0% - there is always some probability of the CR
81
What is spontaneous recovery?
when the CR reappears for no apparent reason
82
What is renewal?
When a change in context (new or old) brings back the response
- If you bring them to a new room, mice will likely get scared as not all rooms are ruled out
83
What is reinstatement?
When random delivery of the old US brings back the response
84
What is savings?
Reduction in amount that is needed to refrain the animal on the same task or a related task (in comparison to the first learning of it)
85
What is the role of the ventromedial prefrontal cortex?
Has inhibitory connections with the amygdala which are responsible for suppressing emotional responses in social situations
- Damage causes impairments in behaviour control and decision making
86
What is the role of serotonergic neurons?
Play inhibitory role in human aggression
- A depressed rate of serotonin release is associated with aggression and other forms of antisocial behaviour
- Drugs that increase the amount of serotonin in the synapse decreases irritability and aggressiveness
PSYC 211
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