Lecture 15

Question 1

Hormone control of puberty

Answer 1

The arcuate nucleus of the hypothalamus produces the neuropeptide kisspeptin. This initiates puberty and maintains reproductive ability by triggering the release of GnRH

GnRH is a hypothalamic hormone that causes the anterior pituitary to produce gonadotrophic hormones.

GnRH causes the hypothalamus to produce FSH and LH (gonadotropic hormones)

UP TO HERE IS THE SAME FOR MALES AND FEMALES

These cause the gonads to release Test or estradiol

Question 2

Male sexual behaviour

Answer 2

Men resemble other mammals in their behavioral responsiveness to test
Normal levels - fertile
Without it, sooner or later, sex stops
Dominant monkeys have sex for longer
Without test, castrated mice don’t bang. Will again if you inject test
Men taking GnRH antagonists have less androgens and low sex drive

Question 3

Female sexual maturation

Answer 3

Estrogen - sex hormones released by ovaries that causes maturation of physical features of females

Estradiol - principle estrogen of many mammals including humans

Question 4

Hormone control of female reproductive cycles

Answer 4

Menstrual cycle

Female reproductive cycle of humans and promotes
Sexual behaviour is influence by ovarian hormones but can happen at any time

Estrous cycle

Mammals that are not primates
Do not menstruate
Reabsorb their endometrium
Only active during estrus part of cycle
Is "in heat"

Question 5

Human female sexual behavior

Answer 5

not much of an influence on female behavior

Big studies show some in sexual deire but small

Question 6

Rodent female sex behavior

Answer 6

Responsive to males in heat
All hormone dependent
Big change
Hormones influence willingness/eagerness to mate and capacity as males cannot mate with those not on heat
Males ignore rats without ovaries but will be interested if she is given injections of estradiol and progesterone

Question 7

Estradiol followed by progesterone does 3 things to female rats

Answer 7

Proceptivity: Eagerness to copulate - seeks out male and entices him

Receptivity: Ability and willingness to copulate - accept advances via lordosis

Attractiveness: Physiological and behavioral qualities that attract the male. Pheromones’ (odors) are onw way. Proceptive behavior is another

Question 8

Hormonal control of sexual behaviour

Answer 8

Organizational effects of hormones on the body is over at birth but on brain lasts a few weeks

So we can masculinize or feminize rodent brains by altering signaling after birth after development of organs is complete

Castrate males at birth stops further androgen signaling - they develop some female behaviors
If they are injected with estradiol and progesterone as adults, they try to get other males to bang them

Introduction of females’ hormones in non-castrated adults does nothing

Question 9

Give adult rats female hormones

Answer 9

Hormone treatment
At birth When grown Resulting sec behavior
None E + P Female: yes M: no
None test F: no M: no

Test E+P F:no M:no
Test test F:no Male: yes

Test early on defeminizes female brains so they wont do sex behaviour when given EP later
Test early on masculinizes brains so they will do male sex behavior when given test later

Question 10

Congenital Adrenal Hyperplasia

Answer 10

Adrenal gland put out too much androgens before and after birth

In males, no drama. Females can get masculinized sex organs in brain and body

Higher likelihood of identifying as a man and being into girls

Higher prevalence of homosexuality’s and trans

This isn’t the main thing though. Other peptides act in the brain. We do not know which

Question 11

Male female brain configurations

Answer 11

if there are 50 sexually dimorphic areas

scan 100 ppl

only 5% have all of them

Most are mosaics

Why? Cos signaling is super different

Question 12

Important pathways for female behavior

VMH

Answer 12

GABA neurons in the medial amygdala
gets sensory input but unprocessed, doe not know what it is, just responds to it automatically
Activates the ventromedial nucleus of the hypothalamus (VMH)
Electrical stimulation facilitates female sexual behavior
Injections of estradiol and progesterone here cause sexual behavior even if animal has no ovaries
Female with bilateral VMH will not do lordosis even with estradiol and progesterone

Question 13

Important pathways for male behavior

Answer 13

GABA on amygdala
MEDIAL PREOPTIC AREA
Electrical stimulation = male behavior
In the mPOA is the SEXUALLY DIMORPHIC NUCLEUS
much larger in males than females
Lesioning the mPOA of females’ does not impact sex but they ignore their offspring
:lesioning males mPOA changes sex behavior but not parenting

Question 14

Pair bonding

Answer 14

5% of mammal species are fairly monogamous pair bonders

2 proteins: vasopressin and oxytocin

Some species of prairie vole form pair bonds and some don’t
Blocking or activating oxytocin receptors on the ventral forebrain influences who they pair with and when
Introducing oxytocin receptors to the non-pair bonding species makes them pair bond

Question 15

Regulation of priorities

Falling in love/becoming a drug addict

Answer 15

Nucleus accumbens in the ventral forbrain has oxytocin, vasopressin, dopamine and serotonin activity
When activated the right way, changes priorities and how you value things
Can cause love and addiction
If not, more coldly cognitively evaluate a situation

Question 16

Pheromones’ (mechanism)

Answer 16

Transmit chemical signals from one animal to another
Odors in humans are learned apart from maybe lavender and rotten fish
In animals more innate
Have a VOMERONASAL ORGAN
finds chemicals
is in nasal cavity
humans do not have a functional VNO
Removal of the VNO, the vomeronasal nerve disrupts the effects of pheromones’

Question 17

Pheromones (effects)

Answer 17

Lee-Boot effect - female mice housed together (no male urine) estrous cycles slow and eventually stop

Whitten effect - Synchronization of menstrual or estrous cycles of females which occurs only in the presence of male urine (may have advantages for childcare if all give birth at once)

Vandenbergh Effect - Earlier onset of puberty seen in females housed with males: Pheromones’ in male urine

Bruce effect - Females terminate permanency following scent of an unfamiliar male (male eats other males offspring, better to abort and have his kids)

Question 18

Pheromones’ in humans

Answer 18

VNO non functional
Women together synchronize period to within a day or two
Women in regular contact with men show shorter cycles than women without men

Maybe

Question 19

2 ideas of emotion research

Answer 19

Mammals have common ancestor so we can use them to study emotions

Cannot know if an animal is just behaving or of they are experiencing emotion

Question 20

Dopamine signaling experiments

Answer 20

All drugs of abuse increase dopamine so people thought it was the pleasure hormone
Intra-cranial self-stimulation in rats sees them doing it again and again
But in humans, dopamine does not increase pleasure
Do animals like dopamine or CRAVE it
Humans crave when dopamine messed with. Perhaps this is not a pleasure hormone

Question 21

Frequency of amygdala stimulation

Answer 21

If GABA stimulation at 5 a second = horny
20x = attack!
Change frequency , change behavior. Do they feel horny or angry or just ACT?

If we stimulate with glutamate, pull back and stop socializing. Depression? Or just the action?

Question 22

Old ideas about emotional expression

Answer 22

6 faces/emotions
Recognition via face is generally automatic, rapid and accurate
More time = no improvement over initial thought
Facial expressions serve a social function
Broadcast emotions and allow us to decide who to trust etc
Innate, natural and unlearned
No cultural or linguistic barrier
36 month old babies mimic facial emotions
Isolated tribes can read westerners and vice versa
No differences in facial expressions in congenitally blind people

Question 23

New ideas about emotional expression

Answer 23

BUT overstated
Expressions are not super specific - the same facial expression can convey different emotions and different facial expressions can convey the same emotion

Inferring emotions from the face is not very reliable. The same emotion is not reliably expressed through nor perceived from a common set of facial movements

The generalizability (contextual and cultural effects) of deducing emotions from faces is not well studies.

Emotional experiences do not reduce to 6 emotions but 25 unique blends. They do not manifest in prototypical facial-muscle configurations alone but in multimodal behavioral expressions such as voice, touch, posture, gaze and head/body movements

Not just face