Hypothalamus

Question 1

What is the role of the anterior pituitary?

Answer 1

Master gland - regulates function of other endocrine glands

Question 2

What is the role of the posterior pituitary?

Answer 2

Secretes oxytocin and vasopressin

Mediates sexual, maternal, fluid balance functions

Question 3

What are the 3 functional divisions of the hypothalamus and what are their roles?

Answer 3

Periventricular zone - neuroendocrine motor zone
Medial zone - controls diverse set of behaviours
Lateral zone - contains neurons expressing substances (orexins and corticotrophin releasing hormone)

Question 4

What do orexins regulate?

Answer 4

Ingestive behaviour

Circadian rhythm

Question 5

What does corticotrophin releasing hormone regulate?

Answer 5

Fluid balance

Question 6

What are the areas of the medial hypothalamus and which behaviours do they control?

Answer 6

Medial preoptic nucleus - reproductive, social
Anterior hypothalamic nucleus - defensive
Paraventricular nucleus - ingestive
Ventromedial nucleus - reproductive, social, defensive
Mammillary body - exploratory

Question 7

Which hypothalamic region is sexually-dimorphic in humans?

Answer 7

Interstitial nuclei of anterior hypothalamus (INAH)

Question 8

What are the proceptive sexual behaviours in male and female rats?

Answer 8

Female - hopping, head-wiggling, 50kHz calls

Males - cruising (searching for females), 50kHz calls

Question 9

What are the consummatory sexual behaviours in male and female rats?

Answer 9

Female - lordosis

Male - mounting

Question 10

What are the post-consummatory sexual behaviours in male and female rats?

Answer 10

Female - intense grooming

Male - intense grooming, 22kHz ‘leave-me-alone’ calls - avoidance

Question 11

Which hypothalamic region is sexually-dimorphic in rats?

Answer 11

Sexually dimorphic neurons in preoptic area (SDN-POA)

Question 12

Which hypothalamic region is active during mating in male rats?

Answer 12

SDN-POA

Question 13

Which receptors are found on SDN-POA neurons?

Answer 13

Testosterone receptors

Question 14

Where does the POA receive input from?

Answer 14

Vomeronasal organ - via medial amygdala and BNST

Question 15

Where does the POA project to and what is the role of this projection?

Answer 15

PAG

Activate spinal MNs for pelvic organs involved in copulation

Question 16

Which hypothalamic area coordinates sexual behaviour in female rats?

Answer 16

Ventromedial nucleus of hypothalamus (VMH)

Question 17

Which receptors are found on VMH neurons?

Answer 17

Oestrogen receptors

Progesterone receptors

Question 18

Which neuropeptides are key to support sexual behaviour?

Answer 18

Oxytocin (OT)
Arginine vasopressin (AVP)

Question 19

Where are oxytocin and arginine vasopressin made?

Answer 19

Posterior hypothalamus

Question 20

What are the peripheral effects of oxytocin?

Answer 20

Uterine contractions

Milk ejection reflex

Question 21

What are the central effects of oxytocin?

Answer 21

Sexual behaviour
Maternal care
Adult social bonding
Adult pair-bonding

Question 22

How do AVP and OT levels change during male rat sexual behaviour?

Answer 22

AVP increase during anticipatory behaviour

OT increase at ejaculation

Question 23

What are Panksepp’s 3 types of aggression and which circuits do they involve?

Answer 23

Affective/defensive attack - RAGE system
Quiet-biting - SEEKING system
Inter-male aggression - circuits interacting with RAGE and SEEKING systems

Question 24

Which brain areas are involved in affective/defensive attack?

Answer 24

Ventrolateral and medial hypothalamus
Dorsal PAG
BNST

Question 25

Which brain areas are involved in quiet-biting?

Answer 25

Dorsolateral hypothalamus | Ventral PAG

Question 26

Which brain areas are involved in inter-male aggression?

Answer 26

Medial amygdala Preoptic and anterior hypothalamus PAG

Question 27

What are the 2 model species of maternal behaviours?

Answer 27

Rat | Sheep

Question 28

What are the characteristics of rat maternal behaviour?

Answer 28

Altricial species Long bonding window Accept alien pups

Question 29

What are the characteristics of sheep maternal behaviour?

Answer 29

Precocial species Short bonding window Selective maternal care - reject alien lambs

Question 30

What hormonal changes occur at the end of pregnancy in rats?

Answer 30

Increased oestradiol and prolactin | Decreased progesterone

Question 31

Which neuropeptide is needed for maternal behaviour induction in rats?

Answer 31

OT

Question 32

Through which brain areas do pup stimuli trigger maternal responses after parturition in rats?

Answer 32

Pup stimuli - medial preoptic nucleus (MPOA) - VTA - NAc - ventral pallidum (VP) - active maternal responses Pup stimuli also activate limbic system - disinhibits NAc and VP - modulates circuit

Question 33

What hormonal change occurs at the end of pregnancy in sheep?

Answer 33

Increased oestrogen

Question 34

Which neuropeptide is needed for maternal behaviour induction in sheep, what triggers its release, and from where?

Answer 34

OT Vagino-cervical stimulation (VCS) of birth From paraventricular nucleus (PVN)

Question 35

Through which brain areas does VCS trigger maternal responses after parturition in sheep?

Answer 35

VCS - PVN - MPOA - VTA - NAc - VP - active maternal responses

Question 36

How does the OT released by VCS lead to maternal selectivity in sheep?

Answer 36

OT induces plastic changes in mitral cell responsiveness - in main olfactory bulb - more cells respond preferentially to lamb odour

Question 37

What causes pair-bonding (monogamy) in prairie voles compared to non-monogamous voles?

Answer 37

Higher OT receptor density in key areas (PFC, NAc)

Question 38

What is the circuit for prairie vole pair bonding?

Answer 38

In males and females - mating causes DA release - from VTA to NAc and PFC In males - AVP release - in lateral septum In females - OT release - in NAc and PFC Concurrent release of DA and OT/vasopressin - consolidates conditioned partner preference

Question 39

What is the role of the NAc-ventral pallidum projection in prairie vole pair bonding?

Answer 39

Relays info to motor system - pair bonding translates to behaviour

Question 40

Which phenomena do OT affect in humans?

Answer 40

Maternal behaviour Sexual behaviour/pair bonding Theory-of-mind-related abilities - memory for faces, inferring others' emotions Trust

Question 41

What is the medial forebrain bundle (MFB) and which areas does it involve?

Answer 41

Dense fibre system | VTA - lateral hypothalamus - NAc

Question 42

Which NT projections run through the medial forebrain bundle?

Answer 42

5HTergic (from raphe nuclei) ACh (from forebrain nuclei) DA (mesolimbic, mesocortical)