21. Sexual dimorphism and behaviour III

Question 1

What is the function of the anteroventral periventricular nucleus (AVPV)?

Answer 1

Contains more dopaminergic neurons in females than males

Confirmed by tyrosine hydroxylase labeling

Question 2

What happens to males with mutated estrogen receptors regarding AVPV structure?

Answer 2

Show female-like AVPV structure

Question 3

What is the sexually dimorphic nucleus of the preoptic area (SDN-POA) larger in?

Answer 3

Larger in males

Size can be affected by castration or testosterone treatment

Question 4

What type of neurons express calbindin in the SDN-POA?

Answer 4

Neurons

Question 5

What is the bed nucleus of the stria terminalis (BNST) characterized by?

Answer 5

Complex dimorphism

Ventral part larger in females; main part larger in males with calbindin-positive neurons

Question 6

What regions are identified as male-enlarged areas in sexual dimorphism mapping?

Answer 6

• Medial amygdala
• Ventromedial hypothalamus
• Bed nucleus of stria terminalis (main part)
• Sexually dimorphic nucleus of preoptic area

Question 7

What regions are identified as female-enlarged areas in sexual dimorphism mapping?

Answer 7

• AVPV (containing dopamine/glutamate neurons)
• Ventral BNST

Question 8

What unique physical trait do female spotted hyenas exhibit?

Answer 8

Enlarged clitoris resembling male penis

Question 9

What characteristics are associated with female spotted hyenas?

Answer 9

• Larger size
• More aggressive
• Socially dominant

Question 10

What causes the sexual dimorphism in spotted hyenas?

Answer 10

Deficiency in placental aromatase and maternal androstenedione exposure

Question 11

What are the two major olfactory pathways that trigger male sexual behavior?

Answer 11

• Main olfactory pathway
• Vomeronasal organ pathway

Question 12

What is the pathway for the main olfactory pathway?

Answer 12

Olfactory epithelium → cyclic nucleotide-gated channels → olfactory bulb → sexually dimorphic hypothalamic nuclei

Question 13

What does the vomeronasal organ pathway control?

Answer 13

Sex-specific courting and ultrasonic vocalizations

Question 14

True or False: BNST neurons show the same calcium responses to male and female stimuli.

Answer 14

False

Question 15

What happens when TRPC2 is knocked out in BNST neurons?

Answer 15

Eliminates discrimination between male and female stimuli

Question 16

What triggers the lordosis reflex in female sexual behavior?

Answer 16

Touch on flanks and perineal regions

Question 17

Which area controls the lordosis reflex?

Answer 17

Ventromedial hypothalamus (VMH)

Question 18

What type of neurons control female sexual receptivity?

Answer 18

Progesterone receptor-positive neurons in VMH

Question 19

What effect does ablation of galanin neurons in the medial preoptic area (MPOA) have?

Answer 19

Fathers ignore pups; mothers ignore their pups; virgin females may attack pups

Question 20

What does optogenetic stimulation of galanin neurons in virgin males do?

Answer 20

Suppresses pup attacks

Question 21

What are the two key neuropeptides that affect pair bonding in voles?

Answer 21

• Oxytocin
• Vasopressin

Question 22

What is the role of vasopressin in male pair bonding?

Answer 22

Critical for male pair bonding

Question 23

What happens when vasopressin antagonists are used in monogamous males?

Answer 23

Reduces partner preference

Question 24

What is important for female pair bonding?

Answer 24

Dopamine signaling

Question 25

What brain activation occurs in humans when viewing images of loved ones?

Answer 25

Activation of ventral tegmental area and caudate nucleus

Question 26

What challenges exist in distinguishing biological vs. cultural influences on human sex differences?

Answer 26

Various behavioral and cognitive differences exist between sexes