Neural and Hormonal Activation of Sexual Behavior - Males

Question 1

Neural and Hormonal Activation of Sexual Behavior

Answer 1

All depend on pre-established “Organizing Effects”

Question 2

Medial Preoptic Area (MPOA)

Where?

Answer 2

of Hypothalamus, including Sexually Dimorphic Nucleus, is critical for sexual behavior

Question 3

Testosterone generally required for

Answer 3

rousal (e.g. castration>decrease), although can vary with learned experience

Question 4

MPOA

Answer 4

Releases GnRH >

Releases Dopamine in response to sexual stimulus

Connects to Tegmentum and Basal Ganglia

Also signals Posterior Pituitary to release Oxytocin (at time of orgasm)

producing Refractory Period before male can respond again

Question 5

release of GnRH >

Answer 5

> Anterior Pituitary releases LH & FSH > Testes release Testosterone

Question 6

Prolactin

Answer 6

released by Anterior Pituitary after ejaculation

producing Refractory Period before male can respond again

Question 7

Nucleus Accumbens

Answer 7

Pleasure!

near Basal Forebrain

• Area also implicated in addiction to amphetamines, cocaine, and chocolate; Rats will stimulate area to death

Question 8

Spinal Nucleus of the Bulbocavernosus (SBN)

Answer 8

• Motor neurons of SBN => rhythmic contractions for ejaculation
• Tegmentum and Basal Ganglia communicate with it

Question 9

Oxytocin

Answer 9

released at time of orgasm

Question 10

MPOA also responds to circulating Testosterone,

Answer 10

increasing its output (short-term positive feedback)

….to input from Medial Amygdala, implicated in Aggression

…to input from Cerebral Cortex (Learning plays a greater role in human sexual activity than in nonhumans)

Question 11

Some correlation between high Testosterone

Answer 11

and Aggression (as in violent crime, tho not nec sexual crime)

Question 12

Medial Amygdala also likely receives

Answer 12

Pheromone input, as well as Somatosensory info from genitals

– In rodents, smell can inhibit aggression toward females, increase aggression toward rival males

Question 13

input from Cerebral Cortex (Learning plays a greater role in human sexual activity than in nonhumans)

Answer 13

• Includes Sensory (including visual identification), Memory, Prefrontal evaluation, and Motor organization
• Can lead to idiosyncratic partner-, place- or object-specific sexual responses