Affiliative and Reproductive behaviour Flashcards

1
Q

Reproduction and affiliative behaviour meaning

A

reproduction- activity animals do to produce more of them. mate → exchange dna info in order to produce offspring

Display different behaviours, attract attention of other sex to try increase the chances of mating.

affiliative behaviour- relationship with other animals that are not intended to reproduce the species (shaking hands, birds flying together)

social interactions are classified as affiliative behaviours

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2
Q

The experimental wedding
Explain the study

A
  • Linda and Nic, both science writers.
  • Studied their ‘love hormones’ during their wedding in Devon (see how these hormones are affected by this experience)
  • Blood taken before and after ceremony
  • Measured oxytocin, vasopressin, cortisol, and testosterone, before and after the ceremony.
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3
Q

The experimental wedding
Results

A
  • Oxytocin (the ‘love hormone’) levels were up.
    — Bride Linda has the highest change- much more oxytocin immediately after the ceremony compared to before.
    — Then mother, father and groom had the highest changes
  • Vassopressin (the “possession hormone”) went down in Nic. (they argued maybe because he was already married to Linda he didn’t feel possession anymore)
  • Cortisol (the ”stress hormone”) was up in Linda before and even higher after the wedding, whereas in Nic cortisol levels went down after the ceremony.
  • Testosterone (hormone related to sexual behaviour in males) levels doubled in Nic.
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4
Q

Castration and hormone replacement: Arnold Berthold
Study and results

A
  • Looking at the maturation of chickens into roosters
  • Looking at castration in these animals- removing testis and see what was the effect on development

Findings:
Group 1: when animal is castrated, development is altered so the animals don’t develop these characteristics (long tail and neck) of the rooster

Group 2: castration and reimplantation of testis- this animal developed normally

Group 3: castration and transplantation of testis (removed testis in chicken 1 and implanted in chicken 2 that was already castrated). Testis transplantation restores normal development in roosters. Transplanted testis were not connected to blood supply or neuronal networks.
Their effect was mediate by chemicals released to the blood stream:
HORMONES!!

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5
Q

What are hormones:
- definition of hormone
- definition of neurohormone
- definition of target

A

Hormone: signalling molecular that can carry messages to distant targets through the blood stream (eg testosterone)
Neurohormone: an hormone released by neurons. Targets neighbouring or distant cells (eg. oxytocin)
Target: organs/cells that can detect hormone/s and it is affected by it/them.

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6
Q

What did Dr John Brinkley investigate in relation to testis transplant in humans with “weak sexuality”

A

Someone was suffering from weak sexuality and they received implant from the testis of goats (in the belly)

The sexual activity of these people became better

Brinkley’s surgeries were a success for some time, but ethical, methodological, and safety aspects made this enterprise unsustainable → which lead to it being stopped

Note: Viagra, introduced in 1998, produced $1B sales that year, highlighting the market for sexual enhancers.

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7
Q

What are the hormone classes

A

Steroid hormones: derived from cholesterol, they can easily travel across cell membranes. e.g., cortisol and progesterone.

Amine hormones: derived from the amino acid tyrosine. Cannot easily cross the cell membrane, so the receptor for this hormone has to be outside expressing in the membrane of the cells. e.g., thyroid hormone (TH). (so the receptor for this hormone has to be outside)

Peptide and protein hormones: amino acid chains (short chain= peptide, long chain= protein hormone). Cannot travel through cell membrane = activate membrane receptors. E.g., oxytocin, vasopressin (peptides), prolactin, insulin (protein).

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8
Q

Where are hormones produced?

A

Sex hormones → female (overies) Estrogen Progesterone, male (testes) Testosterone

Non sex hormones (both in females and males) →
- Growth hormone (GH) from pituitary gland (in brain)
- Thyroxine (TH) from thyroid gland
- Insulin from pancreas
- Adrenaline (ADH) from adrenal gland

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9
Q

Genetic sex and meiosis

A

Defined by the combination of chromosomes we receive from our parents

Offspring genetic sex depends on the sex chromosome carried by the sperm and egg
(ovum) that generates them.

Meiosis- splitting in half the chromosomal content of the cells of these people. Each one of the cells produced by meiosis has half the content of chromosomes. When these combine together and over with the sperm of the other male, they can produce different individuals of different sex

  • X copy of chromosome from mother and X from father → they will become genetic females
  • X copy of chromosome from mother and Y from father → they will become genetic males
  • So…Genetic sex depends on the father sperm cells, which carry X or Y sex chromosomes.
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10
Q

Development of sex organs:
1- info present?
2- what is exposure to sex hormones responsible for
3- what does the Y chromosome control?
4- list sex hormones

A

1- All the information to develop bodies of either sex is present in the 22 nonsex and the X chromosomes.

2- Exposure to sex hormones, both before and after birth, is responsible for sexual dimorphism.

3- The Y chromosome controls the development of the glands that produce the male sex hormones (testosterone).

4- Sex organs: gonads (ovaries and testes), internal sex organs, and external genitalia.

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11
Q

Gonads:
- what are they in terms of development
- ______ gene expresses _______ protein which differentiates ______ into _______
- lack of _____ results in ______

A

Gonads (testes or ovaries) are the first to develop: produce ova or sperm, and hormones.

Sex-determining region Y (SRY) gene (from Y chromosome) express SRY protein that differentiates gonads into testes.

Lack of SRY results in ovaries development (become female version)

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12
Q

Internal sex organs:
- what happens at 2 months of gestation?
- what happens at month 3?
- what do female internal organs not need?

A
  • During the first two months of gestation, fetus can develop into either male or female.
  • At month three, if testes are present and producing hormones (anti-Müllerian hormone and androgens), the internal sex organs develop into male ones.
  • Female internal organs do not need the presence of any other hormone to develop.
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13
Q

2 hormones linked to internal sex organs

A

anti-müllerian:
- Precursor of female internal sex organs is called the Müllerian system
- This hormone that is produced by the testicles will stop that system from developing- will stop that organ from becoming ovaries

Androgens also influence the development of the testicles

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14
Q

External genitalia:
- what do they not need to develop into female organs
- what develops external genitalia into male version?

A
  • As with internal sex organs, external genitalia do not need hormonal influence to develop into female organs.
  • Dihydrotestosterone (androgen produce by testes) develops external genitalia into male version
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15
Q

Sexual maturation:
1- what characteristics are concerned with this section + development and influence
2- what does the hypothalamus release and implication
3- what do testes and ovaries release
4- what are responsible for development of secondary sexual characteristics in males and females?

A

1- Secondary sex characteristics develop during puberty and are influenced by hormones. (Addams apple, facial/ pubic hair, wide hips in females)

2- The hypothalamus release gonadotropin-releasing hormone (GnRH), which ultimately stimulates hormone release by testes or ovaries.

3-
- Testes release testosterone (androgen)
- Ovaries release estradiol (estrogen)

4- Gonadotrophins (testosterone and estradiol) are responsible for development of secondary sexual characteristics in males and females, respectively.

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16
Q

Hormonal control of sexual behaviour:
1- what do hormones do?
2- example
3- sexual behaviour in non-primates / primates

A

1- Hormones not only control sexual development, but also interact directly with the nervous system to affect sexual behaviour.

2- E.g., hormones control the female reproductive cycle: the menstrual cycle (estrous cycle in non-primate mammals)

3-
- In non-primate females, sexual behaviour is linked to ovulation (sexual behaviour is only present when the female receptive- it can be fertilised)
- Primate females mate at any time during their menstrual cycle.

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17
Q

Hormonal cycle

A

What we know is that there are different hormones produced by different sections of the body and that these hormones will produce the cycle. Eg. the FSH is produced by the pituitary gland in the brain and that will trigger the production of estradiol which will peak in the ovaries. And this chemical that is released by the ovaries in females will impact the pituitary organ and it will release luteinising hormone. This is the ovulation part of the cycle, once the ovas is away from this follicule, then the corpus lutem is not producing estradiol and progesterone (the 2 female hormones). And this will effect the uterus in preparation for that egg if it is fertilised and is eventually implanting individuals.

sum:
FSH → estradiol → LH → ovulation → estradiol + progesterone (from corpus luteum)

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18
Q

Hormones and sexual behaviour in male rodents:
1- list 3 stages of male rodents sexual behaviour
2- depends on?
3- what happens when animals are castrated?
4- what happens when animals are injected with testosterone?

A

1- mounts, intromission, and ejaculation

2- Depends on testosterone levels: castrated male rats injected with testosterone reinstate sexual behaviour.

3- When animals are castrated, that behaviour goes down. The testicles are not producing these hormones anymore

4- If animals are injected with testosterone, the behaviour goes back- just the injection of testosterone in the bloodstream makes the animal behave again sexually.

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19
Q

What is sexual behaviour in female rodents called?

A

Lordosis

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20
Q

Hormones and sexual behaviour in female rodents:
1- what does the female initiate and what happens when receptive
2- what does sexual behaviour depend on? What do ovariectomised rats display?
3- what does ER and ER -/- stand for?
4- what happens for ER and ER -/- animals?
5- similar effects with?

A

1- The female initiates copulation. When receptive, it will approach the male.
2- Sexual behaviour depends on estradiol and progesterone. Ovariectomised rats (ovaries removed) display no sexual behaviour.
3- ER: estradiol receptor. ER -/-: ER knockout rats
4- Females with no ER have no receptivity for males. The knockout animals do allow for some mounts to take place but there is no intermission. This is because there is no signalling through this estradiol received in different parts of the brain because the receptor is not there.
5- Similar effects with progesterone receptor KO females (Lydon et al., 1995).

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21
Q

Neural control of sexual behaviour: tools

A
  • Retro-tracing to define the circuit that control sexual organs (e.g., Marson & Murphy, 2006). Injection of pseudorabies virus (retrograde tracing) in sexual organs (penis, vagina, clitoris). They can trace up to the brain where the neurons that control the sexual organs are located.
  • Activation of Fos, a marker of neuronal activity, in key brain regions.
  • Identify of neurons containing sex hormone receptors: estrogen and progesterone or testosterone.
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22
Q

Neural control of sexual behaviour: Males
Spinal mechanisms

A
  • Men don’t have control of some of the sexual behaviour that happens at the level of the spinal cord
  • Men with complete spinal cord transection above the 10th thoracic segment can ejaculate (but they don’t know)
  • A group of neurons in the lumbar region (spinal ejaculation generator) lumbar spinothalamic (LSt) cells control ejaculation.
  • Destruction of LSt cells in rats abolishes ejaculation, without affecting mounts or intromissions.
23
Q

Neural control of sexual behaviour: Males
Brain mechanisms
1- what is the main region of the brain that controls sexual behaviour
2- what will destruction of this area cause
3- within this MPA what is there?
4- what will this area project?
5- what will this release?

A

1- medial preoptic area
2- stops all sexual behaviour
3- sexual dimorphic nucleus
4- an inhibitory control on this part of the medulla
5- the inhibition of the sexual behaviour

24
Q

Neural control of sexual behaviour: Males
Brain mechanisms - summary

A

Medial preoptic area → PAG
Medial preoptic area → nPGI of medulla → mating behaviour

25
Q

Explain about the Sexually dimorphic nucleus (SDN)

A
  • 3-7 times larger in male rats than females.
  • Larger in human males than females.
  • Involved in gender identity.
  • Lesions to SDN decrease masculine sexual behaviour
26
Q

Neural control of sexual behaviour: Females
Brain mechanisms
1- main region of the brain that controls sexual behaviour
2- what will destruction of this area cause
3- what connections between different regions
4- sequence of events?

A

1- Ventromedial Nucleus of hypothalamus (VMH) → lordosis
2- stop all sexual behaviour
3- excitatory connections
4- VMH → PAG of midbrain → nPGi of medulla → mating behaviour

27
Q

What is fos?

A

neuronal activation marker

28
Q

Parental behaviour:
- what species show it?
- what control
- most research on?
- mice/ rats pups at birth
- what is one of the first maternal behaviours during gestation?

A
  • Most mammalian species show parental behaviour.
  • Hormonal and neuronal control, mostly based on rodents.
  • Most research on maternal behaviour.
  • Mice/rats pups at birth:
    – Blind
    – Do not regulate their own temperature
    – Cannot release urine and faeces
  • Nest building is one of the first maternal behaviours during gestation
29
Q

Maternal behaviour

A
  • Birth assistance by pulling the pups gently.
  • Nursing.
  • Periodical licks pups’ anogenital region to stimulate urination and defecation (a way of recycling water – very useful under low water availability).
  • Pups retrieval if they leave or are removed from the nest.
  • Maternal behaviour is influenced by prenatal hormones, but passage of pups through the birth canal also helps (Yeo & Keverne, 1986).
30
Q

Maternal behaviour:
- what can influence maternal behaviour
- eg. linked to nest building
- what is crucial for maternal behaviour
- what is also necessary for maternal behaviour and when is it activated?
- finding of pups compared to cocaine
- what has been shown with human mothers and pictures of their babies compared to strangers?

A
  • Hormones can influence maternal behaviour, but do not control it.
  • I.e., progesterone, the main pregnancy hormone, can facilitate nest building. But, nest building continues after birth, when progesterone is significantly lower.
  • Medial preoptic area (MPA; involved in male sexual behaviour) is crucial for maternal behaviour.
  • The VTA-NAC pathway, involved in the reward system, is also necessary for maternal behaviour. It is activated when mothers encounter pups.
  • Encountering pups is more rewarding than cocaine in lactating females (Ferris et al., 2005).
  • Human mothers show activation of the reward system when presented with pictures of their babies as opposed to other babies (Bartels & Zeki, 2004)
31
Q

Monogamous prairie voles vs polygamous male meadow voles

A

Monogamous prairie voles share offspring care whereas polygamous male meadow voles leave the female after mating.

32
Q

What is the Medial Preoptic Area role and size/ lesions in prairie and meadow voles

A

MPA: lesions disrupt maternal behaviour

  • Size of MPA is less sexually dimorphic in prairie voles than in meadow voles.
  • MPA lesions disrupts paternal behaviour in rats and prairie voles.
33
Q

Affiliative behaviours
- what are they?
- what can they involve?
- what are key for complex social behaviours?

A
  • Positive social behaviours within the same or different species.
  • Can involve individuals of the same or different sex.
    – Formation of pair bonds in voles.
    – Prosocial behaviours in humans.
  • The neuropeptides oxytocin (OXT) and vasopressin (VP) are key for complex social behaviours.
34
Q

Oxytocin and vasopressin:
- where are they produced?
- how can they be released?

A
  • produced in the hypothalamus.
  • They can be released in two ways:
    — from the posterior pituitary gland as hormones.
    — Or from synaptic release- axons projecting to specific brain regions, as a neuromodulator or neurotransmitter. (brain regions include amygdala, NAc- reward system, ACC)
35
Q

Pair bonding:
- how many mammals are monogamous?
- biparental species?
- prairie and meadow voles linked to monogamous and polygamous

A
  • Only 3-5% of mammals are monogamous.
  • Biparental species: males and females raise the young.
  • Voles are a prime example:
    – Prairie voles: monogamous – bond for life.
    – Meadow voles: polygamous or promiscuous – male leaves the female after mating. Female raises pup on their own.
36
Q

Explain how hormones influenced pair bonding (Cho et al., 1999)

A

Exposure to a partner while injected with VP or OXT increased the preference for that partner.

  1. Male and female paired for 1h. One of them receives intraventricular administration of OXT or VP. The animal that receives the injection is the target for the experiment.
  2. Then animals are submitted to a partner preference test (180 min) where they can choose to spend time alone, with a stranger, or with the partner they were exposed during drug administration.
37
Q

Hormones influencing pair bonding:
Explain the partner preference test

A
  • Box with 3 compartments
  • Compartment on the left- partner of the previous interaction can stay there and interaction
  • Compartment on the right - new animal
  • The time they have in physical contact with partner depending on the injection they receive during the interaction
  • If the animals are controlled, both the partner and the stranger have a similar amount of interaction
  • If the test animal was injected with vasopressin during the interaction, then the preference for the partner is increased. This is also true for vasopressin in males and oxytocin in males. For females it is the same- vasopressin and oxytocin injection increase preference for the partner they interacted with before

Sum- preference for the pair is mediated by these hormones in the system

38
Q

What is pair bonding associated with?

A

The density of VP receptors in the
rewards areas of the brain.

39
Q

Neurobiology of pair bonds

A

After mating and cohabitating with a female,
a male prairie vole tended to spend
significantly more time in contact with the
partner (filled columns) than the stranger
(open columns).

Pattern of expression of vasopressin receptor
(V1a, left) and dopamine D2 receptor (right)

Expression of vasopressin receptor in middle section of the brain is highly rich in the prairie vole compared to the meadow vole.

The hormone is hitting areas of the brain that are now expressing more receptors, this is why these animals are more sensitive to the hormone

control- no difference between prairie and meadow voles indicating its not that all receptors in the brain of the meadow vole are affected. Its only these particular ones that are mediating the effect of these hormones

40
Q

Which vole is the vasopressin receptor highly expressed in? (+what brain regions)

A

Vasopressin receptor is highly expressed in prairie voles compared to meadow voles

Lateral septum and ventral palidum

41
Q

Where are OXT receptors highly expressed?

A

OXT receptors are highly expressed in PFC and Nacc in prairie voles.

Strong expression of OXT receptor in the NAcc in the prairie voles compared to the meadow voles (NAcc is involved in mediating the reward)

42
Q
  • What happens if OXT or VP is blocked?
  • What does having an antagonist mean?
A

Partner preference in prairie voles

Having an antagonist makes the preference for the partner go away- the animals cannot distinguish anymore. The same happens with an antagonist of OXT.

43
Q

Lim et al., (2004) what enhanced mate preference in meadow voles

A

(The prairie vole has preference for the partner
The meadow vole does not have preference for the partner)

  • Overexpression of vasopressin receptor in the ventral pallidum (V1aR-vp) enhanced mate preference in meadow voles.
  • When the meadow voles are injected in the accumbens with the vasopressin receptor- they now have a preference for the partner.
  • For looking at the result for individual animals: the controls are spread around the 50% chance of spending time with partner where as animals that over express that vasopressin receptor all prefer to be with a partner.
44
Q

Formation of pair bonds in humans

A
  • Oxytocin and vasopressin seem to influence pair bonding in humans too, but manipulating these carry ethical concerns, so we do not know for sure.
  • OXT intra-nasal caused relaxation and anxiety reduction in humans (Heinrichs et al., 2003).
  • Maternal and romantic love activated regions of the brain rich in vasopressin and oxytocin receptors.
45
Q

What is prosocial behaviour?

A

The term “prosocial” is associated with a wide range of positive social behaviours, including trust, cooperation, care, empathy, and altruism—all of which are key for forming and maintaining adaptive human social relationship

eg. someone sharing an umbrella with you

46
Q

What effects of social behaviours in humans does administration of oxytocin have?

A
  • Trust
  • Empathy
  • Social approach
  • Altruism
47
Q

Role of oxytocin in prosocial behaviour

A
  • Oxytocin has effects on brain regions related to reward and fear related processing.
  • Growing interest in translating oxytocin administration for the treatment of psychiatric conditions ranging from anxiety disorders to autism spectrum disorder.
  • Oxytocin effects on behaviour are highly influenced by individual and contextual conditions.
  • Oxytocin and vasopressin can be manipulated by methods such as a nasal spray of oxytocin (love spray)
48
Q

Oxytocin and trust: Kosfeld et al. (2005)
Study

A
  1. Both the investor and the trustee were given an initial payment of 12 monetary units (MU).
  2. The investor may choose to give 0, 4, 8, or 12 MU to the trustee.
  3. The experimenters were triplicating the donated MU.
  4. The trustee could give back to the investor 0-48 MU,
    depending on the donation.
  5. Placebo or OXT administered to Investors 50 minutes before the task.

(trust = firm belief in the reliability, truth, or
ability of someone or something)

49
Q

Oxytocin and trust: Kosfeld et al. (2005)
Results

A

Subjects given oxytocin show significantly
higher MU transfer levels.

Investors who received OXT, most of them decided to give all of the money to the trustees

50
Q

Oxytocin and altruism: Marsh et al., (2015)

A

Experiment 1:
1. Saliva samples to measure internal OXT.
2. Participants received 10 €1 coins.
3. Social or environmental donation task.

Results:
* Positive correlation between OXT levels
and social donation.
* No effect in the ecological frame.

Experiment 2:
1. OXT intranasal.
2. Participants received 10 €1 coins.
3. Social or environmental donation task.

Results:
OXT administration increased donations
in the social frame, but decreased those
in the ecological frame.

(Altruism: non-reciprocal prosocial acts which are aimed at improving the welfare of
another individual at a personal cost to the altruist.)

51
Q

Oxytocin and empathy: Marsh et al., (2015)

A

Experiment:
1. OXT or placebo, intranasal.
2. 45’ later, “Multifaceted Empathy Test” (MET). (Questions asked to pp’s to establish their empathy ratings of those scenarios)

ED: direct emotional empathy
EI: indirect emotional empathy

Results:
OXT administration increased empathy ratings in all dimensions

(Empathy: cognitive (recognising emotional states in others) or emotional (sharing
experiences of emotional states perceived in others).

52
Q

Oxytocin and social approach: Preckel et al., (2014)

A

Approach behaviour to others was measured after intranasal OXT in women.

Experiment:
1. OXT or placebo, intranasal.
2. 45’ later, Stop Distance Paradigm with female or male experimenters

Results:
- OXT administration decreased the social distance that female participants kept between
themselves and an unfamiliar friendly (and attractive) male experimenter.
- Pp’s receiving OXT are wiling to accept much shorter distances
- Only in the male partner is where this effect is produced

53
Q

Role of oxytocin in prosocial behaviour

A
  • The involvement of oxytocin in prosocial behaviour seems to be more complex than simply increasing one dimension specifically.
  • Expression of OXT and OXT receptor maps into areas involved in anticipatory, appetitive, and aversive cognitive states.
  • maps for 3 genes
  • brain regions that are involved in anticipatory situations (eg NAcc or VTA) correlate highly with expression of OXT
  • repetitive signalling (when something is rewarding, like sexual interactions or something is tasty) the parts of the brain that are activated also express these OXT genes
  • aversive is also highly correlated
  • sum- this interpretation of OXT should be taken with a pinch of salt because OXT is very complex. It produces many things which maybe secondarily affect prosocial behaviours.