Neural and Hormonal Activation of Sexual Behavior - Males Flashcards
Neural and Hormonal Activation of Sexual Behavior
All depend on pre-established “Organizing Effects”
Medial Preoptic Area (MPOA)
Where?
of Hypothalamus, including Sexually Dimorphic Nucleus, is critical for sexual behavior
Testosterone generally required for
rousal (e.g. castration>decrease), although can vary with learned experience
MPOA
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
release of GnRH >
> Anterior Pituitary releases LH & FSH > Testes release Testosterone
Prolactin
released by Anterior Pituitary after ejaculation
producing Refractory Period before male can respond again
Nucleus Accumbens
Pleasure!
near Basal Forebrain
- Area also implicated in addiction to amphetamines, cocaine, and chocolate; Rats will stimulate area to death
Spinal Nucleus of the Bulbocavernosus (SBN)
- Motor neurons of SBN => rhythmic contractions for ejaculation
- Tegmentum and Basal Ganglia communicate with it
Oxytocin
released at time of orgasm
MPOA also responds to circulating Testosterone,
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)
Some correlation between high Testosterone
and Aggression (as in violent crime, tho not nec sexual crime)
Medial Amygdala also likely receives
Pheromone input, as well as Somatosensory info from genitals
– In rodents, smell can inhibit aggression toward females, increase aggression toward rival males
input from Cerebral Cortex (Learning plays a greater role in human sexual activity than in nonhumans)
- Includes Sensory (including visual identification), Memory, Prefrontal evaluation, and Motor organization
- Can lead to idiosyncratic partner-, place- or object-specific sexual responses