gender and nervous system

Question 1

Explain why women have a lower incidence of aphasia and relate this to gender-based differences in functional representation in the cerebral cortex.

Answer 1

Smaller strokes can produce aphasia in men more easily than women. Language representation in the left hemisphere in men is more discrete (i.e. more tightly localized to the classic Broca’s area) than it is in women.

Question 2

What is responsible for gender differences in brain development

Answer 2

Testosterone and Mullerian duct inhibitory Hormone (MIH) secretion by the developing testes during embryogenesis. Without these hormones, a female brain will develop. Testosterone is converted to estradiol and 5-DHT so both androgen and estrogen receptors are important in this process

Question 3

Organizational vs activational effects

Answer 3

The ability of circulating steroids to permanently alter the state of the body or brain during an early developmental critical period is referred to as an “Organizational Effect”. Activational effects are short term effects of steroids that occur in adult system

Question 4

Describe male vs female preoptic area and anterior hypothalamus

Answer 4

LR-releasing hormone is released from pre-optic area into portal system, stimulating release of LH and FSH. In women, the LHRH neurons are linked by gap junctions so discharge is synchronized resulting in larger cyclic release of FSH and LH. Exposure of fetus to testosterone prevents junctional coupling of these neurons

Question 5

sexually dimorphic brain structures

Answer 5

corpus callosum, the lateral fissure, and parts of the amygdala

Question 6

Compare language function in men vs women

Answer 6

In women, language is distributed in Brocas area, plus farther anterior in prefrontal cortex and may be represented more bilaterally. In men, language is discretely localized in Brocas area in lower part of prefrontal cortex

Question 7

Main source of estrogen in brain

Answer 7

Comes from brain itself, NOT gonads. Many neurons in brain contain aromatase and transform steroids into estrogen

Question 8

Describe 3 mechanisms of fast steroid effects on brain in adult

Answer 8

1. Membrane-associated and cytoplasmic classical steroid receptors (ERα or ERβ acting through second messenger systems rather than via DNA-binding mechanisms. 2. Unknown cell surface steroid receptors acting via second messenger systems. 3. Direct allosteric interaction between steroids and GABAA receptors.

Question 9

Explain how the cerebral cortex and hippocampus can be major targets for the effects of androgens.

Answer 9

don’t know