Lecture 14 Flashcards
Sleep molecule hypothesis
SCN makes sleep regular, what decides how much we sleep?
Build up of adenosine during wake/massive drop even with a small amount of sleep
Drowsiness and duration of sleep are modulated by adenosine receptor signaling in the brain
Caffeine - promotes carousal - is an adenosine antagonist
Likely adenosine is one of the chemicals that builds up which makes us sleepy
Norepinephrine neuron activity
Serotonin activity
rises with concentration and focus
Locus coeruleus - makes it
correlates with cortical arousal (as measured by EEG) and drugs that increase serotonin function tend to suppress REM sleep
Raphe nucleus - makes it
Made in brain stem, distributed all over brain
5 hormones that seem to control arousal
All found in neurons that are active when aroused and alert and dropped in slow wave sleep Histamine Serotonin Norepinephrine Ach Hypocretin/Orexin
Histamine and orexin
neuropeptides
Only made in hypothalamus
Antihistamines are histamine blockers
The first generation antihistamines caused drowsiness
Neural control of sleep/wake behaviour
Neurons in the ventral lateral preoptic area (vIPOA) of the hypothalamus promote sleep
INHIBIT arousal centers
Electrical stimulation causes drowsiness and sometimes immediate sleep
Lesions suppress sleep and cause insomnia
They inhibit wake-promoting neurons such as histamine or serotonin neurons
The sleep/wake flip-flop circuit
The vIPOA receives inhibitory inputs from the areas it inhibits
So there is reciprocal inhibition
both cannot be active at once
Animal is awake when the wake-promoting system is more active than the vIPOA
Asleep when not
Sleep molecule 2
Adenosine receptors are expressed by many neurons in the brain
Excites vIPOA and inhibits ACh
So the idea is that the build ip promotes vIPOA and inhibits Ach
Reduces arousal and promotes sleep
In sleep, adenosine is cleared and the animal wakes up
Orexin/hypocretin
Made in hypothalamus
promotes wakefulness
LH orexinergic neurons have inputs from hunger and satiety and also the SCN
Allows them to influence wakefulness
Narcolepsy
Sleep disorder
Excessive daytime sleepiness and urge to sleep
Hereditary autoimmune disorder for most
Death of orexin neurons in the hypothalamus
REM in the waking state
Cataplexy - complete paralysis that occurs while awake
Often due to a strong emotion or physical effort
Sleep Paralysis - REM associated paralysis just before a person falls asleep
Often with vivid dream-like hallucinations
Determining the stages of sleep
Orexin neurons weigh in on sleep/wake cycles but also sleep stages
Without them, sometimes REM comes on while awake
When these people sleep - straight to REM
Narcolepsy people wake up a lot at night cos in REM sleep which is light and easy to wake from
A lot of knowledge about sleep comes from
sleep disorders
Insomnia
Difficulty falling asleep or awakening in the night
25% of population, 9% regularly
Fatal Familial Insomnia/Sporadic Fatal Insomnia
Worsening insomnia Hallucinations Delirium Confused states Can be inherited (normally) but also spontaneous No cure Die after 18 months from onset
Michael Jackson
Died to to anesthetics
Had insomnia
Doc put him to sleep nightly
Cos anesthetics do the same thing
Non-REM parasomnias
Sleep-X
Sleep terrors
Sleep disorders that occurs in NREM or transitions out of sleep. The brain can get caught between a sleeping and waking state. Many are unaware they do this.
Sleep: Walking, talking, crying, eating, sex, teeth-grinding. More prevalent in kids. Episodes last seconds to minutes or longer. Can be caused by medications or conditions.
1st half of the night.
Usually grown out of/gone by 12 years old.
Sleep terrors - overwhelming terror on waking. Can include panic or screaming and harm caused by rash actions. Sometime shave no recollection of these events. Prevalent in PTSD.
REM sleep behavior disorder
Does not become paralyzed during REM sleep
Can act out dreams
Maybe neurodegenerative
Associated with better known neurodegenerative conditions like Parkinson’s
Sexual dimorphism
Two sexes of same species exhibit different characteristics beyond their sexual organs
Can be subtle or exaggerates and include secondary sex characteristics at puberty
associated with genetic and hormonal differences before and after birth
Sexual dimorphic behavior
behaviors with different forms or frequencies across males and females
Mammals have this in mating behavior
Brain gives rise to this as it is a sexually dimorphic organ
Genes and socialization both play roles in this
We do not know which is more important
Differences in the sexes
Can be caused by biology, socialization or the two
There are differences in mix of talents, temperament and interests
If you cannot study this you cannot treat mental illness
Even though some say you should not because genderless society is good
Sex and gender terminology
Sex is defined at birth by chromosomes, hormones and organs
Gender refers to the range of characteristics that pertain to masculinity and femininity, which are the characteristics associated with men and women, respectively. Reflect biology and culture
Gender expression is the expression of masculinity or fem
Gender role is the behaviors deemed appropriate for people of a given sex
Sexual behavior refers to sexual acts performed by people
Sexual orientation one’s enduring sexual attractions
Sexual identity individuals conception of themselves in terms of whether they identify or not with a sexual orientation
Gender identity is one’s personal sense of their gender.
Gender is a social construct
Consensual rules for determining gender and race designations differ across time and cultures
Independent of biology
Understanding and categorization of masculine/feminine are socially constructed from our shared xp
Biology influences these but its contributions are not decisive
Biology’s influence differs with the strength of the cultural inputs
Brains and behaviors are outcomes of conditioning and biology
Differences between sexes
There are _____ difference between the brains of men and women
There are _____ differences between the behavior of males and females’
The adjective placed in here is all to do with the opinion of the person making the statement about how much the culture should influence this
In genderless culture biology exerts it biggest effect as not masked
Socialization
Kids are taught by parents of something is good or bad
Kids are often racist. It is parents that socialize that kid depending on their opinion
WE ASSIGN the value to innate behavior. It is just THERE
Sex determination
X and Y chromosomes are SEX chromosomes
Gonads - ovaries or testes make sperm or ova
Gametes have 23 in total
Sex is determined by 5 factors at birth
Sex chromosomes: XX XY
Sec hormones: Androgen signaling
Gonads: testes/ovaries
Internal reproductive anatomy
External anatomy
(3 categories of sex organs)
Usually all 5 are male or female. If not = intersex
Embryonic sex organs
All embryos contain the precursor to male and female sex organs
In the second month of gestation, the undifferentiated gonads develop into testes or ovaries
In the theirs month, the Mullerian (female) or Wolffian (male) system develops and the other withers
Male sex organ development
The SRY gene on the Y chromosome overpowers all others
Grow testes
XXY also grow testes
SRY gene
Testes
Anti-Mullerian hormone - stops development of internal female sex organs
Test - triggers development of male sex organs via Wolffian system
DHT comes from test. Triggers development of external sex organs
Female sex organ development
XX
Silent until puberty
No anti Mullerian hormone so female sex organs develop
No test so external female sex organs develop
Female development is the default
You must have XX to have ovaries. One X is not enough
Genetic abnormalities - female sexual organs internal
XO - turners syndrome
XY but bad SRY gene - Swyer syndrome
Female internal sex organs develop but NO OVARIES so at puberty, no change.
STERILE
Can develop given hormones at puberty but are still sterile
Genetic abnormalities - male sexual organs internal
Two or more X chromosomes and an SRY gene eg XXY or XXXY
Develop as males with small testes, often sterile and have trouble growing a beard
Genetic abnormalities - Mullerian issues
XY male chromosomes and SRY gene but with either insufficient anti-Mullerian or no receptors
Testes so male characteristics develop. No defeminization
Male and female organs
Often functional male external organs
Androgen insensitivity syndrome
no masculinization
No internal sex organs develop
External female genitalia
Identify as hetro woman who is sterile with a short vagina
Grade 1 is mild - external male genitalia
Grade 6-7 is severe - female external genitals
Grade 2-5 are in between with mixed genitalia
Sex hormones
Influence development of body and brain. Permeant effects, put you on a track going forward.
Behavioral determinization - organizational effect of androgens on brain that prevents animals from displaying female-typical behaviors in adulthood
Behavioral masculinization - organizational effect of androgens on brain that causes animals to display male-typical behaviors in adulthood
Activational effects - puberty causes sex hormones’ to be released by the gonads which influence body and mind.
Ovulation/horniness
How the mind responds to this in adulthood depends how the body and brain were organized by hormones’ signaling in utero
