Sensitive periods for hormonal organization, neural bases of sex

What is sexual brain development regulated by

Presence of absence of T

When do steroids have an organizational effect

When present during a sensitive period in early development

When is the neonatal period

Before birth or just afterwards

What does replacement T do in adulthood

Does not produce “male like” behaviours

Can giving estrogen to castrated adult male rats induce female behaviours

yes

Does testosterone directly masculinize the brain

no

How does T get converted to estradiol

The enzyme aromatase

Why can’t mother’s estrogens masculinize female fetuses

circulating estrogens are prevented from entering a developing brain

what does a-fetoprotein do

protects brain from being masculinized by maternal estrogens

how does a-fetoprotein protect the brain

binds to free floating estradiol, preventing entry into brain
does not bind to androgens, T is allowed to enter brain and be converted

what structures do neural control of sexual responses involve

cortex and spinal cord

what pathway does sensory information from the genitals follow

dorsal column-medial lemniscal

what role does the PNS play

controls genital engorgement and erection

what role does the SNS play

controls ejaculation and orgasm

what are sexual dimorphisms

difference of males and females

What do differences in concentration of receptors result in

steroid effects localized to different areas of the brain

what are the steroid sensitive regions

cortex, brainstem nuclei, medial amygdala, hippocampus, and much of the hypothalamus

what is the role of the ventromedial hypothalamus

monitors changes in hormone levels

aromatization hypothesis

in rodents, estrogen drive masculinization (T is converted to E in the brain) less clear effects on primates