PSYC342 MIDTERM 2

2 fundamental processes noted on aspects of sexual response

1. Myotonia (muscle tension)

2. Vasocongestion (swelling)

4 phases of the sexual response cycle by Masters and Johnson

1. Excitement

2. Plateau

3. Orgasm

4. Resolution

Kaplan’s 3 stage model of sexual response cycles

1. Desire

2. Excitement

3. Orgasm,

What happens to male sexual behaviour if we remove testes in adulthood

Reduces the frequency of all male mating behaviours

Definition of Appetitive behaviour

Behaviours on how to get near a goal

Definition of consummatory behaviours

What you do when you’re at a goal

Definition of precopulatory behaviours

Putting distance/coming back within copulatory bout

What is the appetitive phase

The sexual motivation phase, behavioural components that involve things like the sex drive/courtship

• males spend longer in this phase

What is the consummatory phase composed of

Series of movements

1. Mounting

2. Intromission

3. Ejaculation

What happens to male mice after ejaculation

Males ignore females - become sexually inactive and lethargic

Definition of the post ejaculatory interval (PEI)

The time between ejaculation and next copulatory series - why no sexual behaviour occurs after ejaculation

2 periods of the post ejaculation intervals

1. Absolute refractory phase - males completely non responsive to sexual, mildly painful or other stimuli during this phase

2. Relative refractory phase - a new or very potent sexual stimulus may elicit responsiveness

What is the Coolidge effect

phenomenon where males have renewed sexual interest and reduced refractory periods when seeing other females while having a current partner

What is the timing pattern for the disappearance of sexual behaviour after male castration

Following castration is first ejaculation then intromission then finally mounting

• androgen treatment restores in reversal order

What hormones can fully restore copulation in castrates

Estrogen (estrogen) and DHT (erection)

What happens with lesions in the mPOA

Disrupts male copulatory behaviours

• Neither T treatment nor access to females compensates for the lesions

What does the mPOA focus on

The motivation of sexually relevant stimuli and coordinates genital reflexes / necessary motor patterns

• critical role for dopamine

How did people first discover dopamines role in sexual behaviour

Parkinson’s patients when injected with L dopa had increased libido and sexual potency

4 important roles of dopamine

Male sexual behaviour

Female sexual behaviour

Maternal behaviour

Thermoregulation

Results of 5 days of hormone treatments after castration

At 5 days, copulatory and mPOA dopamine recovery was seen in most castrates

• complete recovery was found around 10 days

• 2 days was not sufficient

2 main roles of the vomeronsasal organs

• picks up pheromones to start sexual behaviour

• For males to be able to discriminate between males and females during mating

What happens if there’s a lesion in the corticomedial area of the brain

Doesn’t allow male rats to smell when females are in heat

What is the route that the pheramones take in the brain

1. Vomernasal organ in the nose

2. Then main and accessory olfactory bulb

3. Then MPOA

4. Then eventually the vomeronasal amygdala

What happens to the pheromone signals once it reaches the vomeronasal amygdala

It sends signals to areas that promote sexual behaviour

Olfactory Bulbectomy experiement on Syrian hamsters and results

Had 4 groups of hamsters - one had sham bulbectomy, one had bilateral, one had ipsilateral and one had contralateral

Results during mating

• sham ones had increased dopamine

• Bilateral didn’t mate and dopamine didn’t increase

• Both ipsilateral and contralateral mated but only dopamine increased in contralateral

What is the conclusion of the olfactory bulbectomy on hamsters experiment

Chemosensory cues are essential for mPOA dopamine release during mating in rodent species

How do males interpret estrous urine after being castrated

Estrous urine continues to increase neural activity in olfactory bulbs but not in mPOA

• T replacement restores mPOA responsiveness

What is the nucleus of the paragigantocellularis (nPGI) and what must be done to it to mate

It is a brain stem nuclei that inhibits the penis from getting an erection

• In order to mate, the mPOA but inhibit it therefore releasing the spinal circuit

Definition of mounting

Behaviour observed among males where male assumes copulatory position but doesnt insert anything

Definition of intermount interval

The interval of time between successive mounts by a male during copulation

Definition of intromission

The entrance of the penis into the vagina

Definition of olfactory bulbs

Rounded structure on front of brain that received input from olfactory sensory cells in nose which then projects to various parts of the rain associated with processing airborne chemosensory stimuli

What is Immediate early genes (IEGs)

Genes that show rapid and transparent expression in the absence of new protein synthesis

• genes are expressed immediately after cells are stimulated by extracellular signals such as growth factors and neurotransmitters

Definition of associated reproductive pattern

Breeding pattern observed in most species where reproductive behaviour / maximal gradual size / high steroid concentrations / gamete production - all coincide together

Definition of dissociated reproductive pattern

Breeding pattern observed in some species where reproductive behaviour doesnt coincide with other functions but instead occurs when steroid levels and gametes are low

What two hormones is sexual behaviour of females dependent on

Estradiol and progesterone during estrus

Definition of Estrus

The period when female mammals will permit copulation

• reproductively active / in heat

• Main goal is repopulation

• Regulated by estradiol and progesterone

Definition of estrous cycles

Regular fluctuations of circulating ovarian steroids that prime the brain so sexual behaviour and reproductive function can overlap

• when estrus occurs

Definition of anestrus

When a female is not in heat

• the opposite of estrus

things that happen when females are in estrus vs anestrus (4)

• females find males more attractive

• Males find these females more attractive

• Males prefer to mount these females

• Only these females will permit mating

3 parts of the estrous cycle

1. Diestrus - 48h - new follicles begin developing, majority of cycle

2. Vaginal proestrus - 12 - estrus behaviour occurs and matting occurs - progesterone increases

3. Vaginal estrus - 36 - hormonal estrus after ovulation (follicles break releasing eggs) - estrogen levels rapidly decline and P levels decline slowly

What happens to the corpora lutea

If egg is fertilized then it remains during pregnancy

If egg isn’t fertilized it withers away

Definition of pseudopregnancy

The corpora lutea remains until next cycle even if copulation wasn’t achieved - slows down the cycle

What are the two main differences between a menstrual cycle and an estrous cycle

1. Menstruation has shedding of inner lining (endometrium), whereas estrous cycles can have little tears to make mini bleeding

2. In menstrual cycle sexual behaviour can occur outside of cycle / max fertility

4 phases of the menstrual cycle

1. Follicular phase

2. Ovulation

3. Luteal phase

4. Menstruation

What phase is the menstrual phase “follicular phase” similar to in the estrous cycle

Similar to the proestrus phase

What is the follicular phase of the menstrual cycle

High levels of FSH are secreted to stimulate follicles in the ovaries

follicle begins to ripen and bring an egg to maturity

Follicle secretes estrogen too

What is ovulation phase of the menstrual cycle

When the follicle ruptures open and releases the ripened egg

What is luteal phase of the menstrual cycle

After releasing an egg, the follicle turns into a corpus luteum which manufactures progesterone

• the progesterone stimulates glands of the endometrium to start secreting nourishing substances

What is the menstruation phase of the menstrual cycle

Sheds the inner lining of the uterus if there’s no pregnancy

6 components of mammalian female reproduction

1. Courtship

2. Mating

3. Ovulation

4. Pregnancy

5. Parturition

6. Lactation

3 components of female sexual behaviour by Beach

1. Attractivity

2. Proeptivity

3. Receptivity

Beach’s idea of proceptivity

Female willingness/motivation to mate

The extent to which females initiate as they play an active role in sexual interaction and copulation

Beach’s idea of receptivity

The females state of responsiveness to sexual initiation of males

Lordosis seems to measure female sexual receptivity

Estrogen and other steroid hormones have big effects too

Sex steroid hormones affect which of Beach’s components of female sexual behaviour

Affects all 3 components

Especially estrogen

Beach’s idea of Attractivity

How attractive a female is to a male

Considered more attractive when they are maximally fertile and females will try to communicate this

Definition of the Flehmen response

Curl upper lip and expose teeth - to smell hormones this way forces chemosignals into vomeronasal organs

Can lordosis be induced

Yes by injections of estradiol and progesterone

• receptive fields increase when estradiol increases

Where does stimulation of the female’s flanks project to

First to the dorsal root ganglion of the spinal cord but then to the medullary reticular formation and the midbrain central gray area

What are the results of lesions in the midbrain central gray region

Reduce lordosis

how does sensory info from the male get to the HYP of the female

Female flank stimulate activates ventromedial nuclei of the hypothalamus x

What is needed to exhibit lordosis

Need both stimulation and hormonal induced brain activation

what are areas with highest density of estradiol and progesterone cells

• mPOA

• Anterior hypothalamus

• Ventromedial hypothalamus

• Amygdala

• Midbrain central gray

What is Estrogen receptor (ERa) required for

Required for the display of sexual receptivity but not essential for female attractivity

3 main theories of the role of estrogen in promoting lordosis

1. Trigger hypothesis

2. Maintenance hypothesis

3. Cascade hypothesis

What is the trigger hypothesis of the role of estrogen in lordosis

One brief pulse of estrogen sets off a chain of events that continues to the end with the display of lordosis

What is the maintenance hypothesis of the role of estrogen in lordosis

Estrogen must be present continuously from the beginning in order for lordosis to be displayed

• however research has found that 2 discontinuous exposures to estrogen could facilitate progesterone evoked lordosis

What is the cascade hypothesis of the role of estrogen in lordosis

Specific and discrete events occur within the neurons of the ventromedial nuclei as a result of initial estrogen receptor binding

• estrogen must occupy receptors at specific critical times in order for lordosis to be expressed

• Similar to the organizational/activational hypothesis

What is female pacing behaviour

A sign of proceptivity

• important because it ensures that she receives a pattern of stimulation as close as possible to the vaginal code

• The optimal pattern of stimulation for producing offspring

Roles of the 4 types of neurons found in the mPOA

Type 1 - signify motivational state represented by solicitations

Type 2 and 3 - fires in response to visceral or somatosensory input

Type 4 - inhibit execution of lordosis

The role of pheromones emitted by females

Effects depend on reproductive conditions of the recipient

• usually acts by suppressing gonadotropin release form the anterior pituitary

The role of pheromones emitted by males

Effects depend on reproduce conditions of recipient

• male chemosignal appears to induce an abrupt release of LH which stimulates follicular growth

• An intact chemosensory system is critical for successful female reproduction

What is androstadienone

A steroid hormone found in men’s sweat - increases blood flow to regions of women’s brains that are tied to sexual behaviour in animals

What is the McClintock Effect

Menstrual pheromones cause women to develop menstrual synchrony

What is the LeeBoot effect

Estrous cycles top in groups of female rodents living together (no males present)

What is the Whitten Effect

Groups of female rodents who are not cycling are exposed to male urine and being cycling synchronously

What is the Vandenbergh Effect

Acceleration of onset of puberty in female rodents exposed to odor of male

what is the Bruce effect

Exposure to using of novel male results in failure of pregnancy in newly pregnant female

Definition of blastocyst

Fluid filled sphere of cells that develops from a zygote

• embryo usually develops from cluster of cells in middle

• whereas the external wall develops into the placenta

What is the female castration response

There’s an increase in gonadotropin concentrations following removal of the gonads, and consequent release from negative feedback effects of sex steroids

Definition of perinatally

Around the time of birth

Definition of antisteroids

Substances that occupy steroid receptors without producing any biological effect

What are 5 neural modules that mediate lordosis

1. Forebrain - inhibits

2. Hypothalamus - responds to steroid hormones

3. Midbrain - gets hyp’s peptides and creates fast signalling

4. Lower brain stem - integrates posture

5. Spinal cord - receives stimulation and produces motor response

Why are there sex differences in parental behaviour

Different types of gametes