Sex and the developing brain / Margaret M. McCarthy.

Format:

Book

Author/Creator:

McCarthy, Margaret M., 1958- author.

Series:

Colloquium digital library of life sciences

Colloquium series on the developing brain ; # 14.

Colloquium series on the developing brain ; 14

Language:

English

Subjects (All):

Brain--Sex differences.

Brain.

Developmental neurobiology.

Brain--Growth.

Sex Differentiation.

Brain--growth & development.

Medical Subjects:

Sex Differentiation.

Brain--growth & development.

Genre:

Electronic books.

Physical Description:

1 online resource (xi, 141 pages) : illustrations.

Edition:

Second edition.

Place of Publication:

[San Rafael, California] : Morgan & Claypool, 2017.

System Details:

Mode of access: World Wide Web.

System requirements: Adobe Acrobat reader.

text file

Summary:

The brains of males and females, men and women, are different, that is a fact. What is debated is how different and how important are those differences. Sex differences in the brain are determined by genetics, hormones, and experience, which in humans includes culture, society, and parental and peer expectations. The importance of nonbiological variables to sex differences in humans is paramount, making it difficult if not impossible to parse out those contributions that are truly biological. The study of animals provides us the opportunity to understand the magnitude and scope of biologically based sex differences in the brain, and understanding the cellular mechanisms provides us insight into novel sources of brain plasticity. Many sex differences are established during a developmental sensitive window by differences in the hormonal milieu of males versus females. The neonatal testis produces large amounts of testosterone which gains access to the brain and is further metabolized into active androgens and estrogens which modify brain development. Major parameters that are influenced by hormones include neurogenesis, cell death, neurochemical phenotype, axonal and dendritic growth, and synaptogenesis. Variance in these parameters results in sex differences in the size of particular brain regions, the projections between brain regions, and the number and type of synapses within particular brain regions. The cellular mechanisms are both region and endpoint specific and invoke many surprising systems such as prostaglandins, endocannabinoids, and cell death proteins. Epigenetic modifications to the genome both establish and maintain sex differences in the brain and behavior. By understanding when, why, and how sex differences in the brain are established, we may also learn the source of strong gender biases in the relative risk and severity of numerous neurological diseases and disorders of mental health. Boys are much more likely to be diagnosed with autism spectrum or attention and hyperactivity disorders, as well as speech and language deficits, compared to girls. By contrast, women are more likely to suffer from affective disorders, such as depression, anxiety, compulsion, and eating disorders and more likely to experience autoimmune and neurodegenerative disorders. Schizophrenia with an early onset is more common in males but a late-onset version is markedly more frequent in females. Male biased disorders have origins in development while female biased disorders are almost exclusively post-puberty. This remarkable shift in disease risk demands our attention. Novel insights into the biological origins of disease are also gained by comparing and contrasting the same processes in different sexes.

Contents:

1. Introduction

2. Sex differences in brain and behavior in context

3. Sex determination versus sex differentiation

4. Masculinization, feminization, and defeminization

5. Steroid hormones are potent modulators of brain development

6. Sex differences in the brain are established during a developmental sensitive window

6.1 Steroid levels in the developing brain

6.2 Early-life programming by hormone effects on the brain

6.3 Mice with null mutations of steroid receptors, steroidogenic enzymes, and binding proteins

7. Sex differences in reproductive physiology and behavior are coordinated

7.1 Ovulation begins in the brain

7.2 Female sex behavior is coordinated with ovulation

7.3 Male physiology and behavior are not temporally constrained

8. Steroids influence multiple endpoints via multiple mechanisms to organize the brain

8.1 Steroids organize the developing brain by altering cell survival

8.2 Steroids organize the brain by altering cell proliferation

8.3 Neuronal migration is not strongly regulated by steroids

8.4 Steroids regulate trophic factors and activity-dependent survival

8.5 Steroids' impact on axonal projections, dendritic branching and connections

8.6 Steroidogenesis occurs in discrete brain regions and affects neuronal development

8.7 Steroids organize the developing brain by altering synaptic connectivity

8.8 Steroids organize the developing brain by altering neurochemical phenotype

8.8.1 Vasopressin is a model of steroid-mediated sexual differentiation of the brain

8.9 The Kisspeptin system is also notable for its sex dimorphism

9. Cellular mechanisms of steroid-mediated organization of the brain

9.1 Prostaglandins masculinize the preoptic area and sexual behavior

9.2 Microglia are sexually differentiated and a source of PGE2 in developing POA

9.3 Gamma-aminobutyric acid induces sex differences in astrocytes in the arcuate nucleus

9.4 Glutamate release is critical to sex differences in synaptogenesis in the hypothalamus

9.5 Endocannabinoids mediate a sex difference in cell genesis in the developing amygdala

9.5.1 Endocannabinoids also regulate sex differences in play behavior

10. Ultrasonic vocalizations differ in neonatal males and females because of a gene called FoxP2

11. Overcoming the hegemony of hormones: genes matter too

11.1 Epigenetics and the development of sex differences in the brain

11.1.1 Epigenetic changes may or may not endure

11.1.2 Multiple epigenetic changes are possible

11.1.3 Epigenetics and sex differentiation

11.1.4 Evidence of an epigenetic "echo"

11.1.5 There is more DNA Methylation in the POA of neonatal females than males

12. Winged messengers: lessons from birds and flies

12.1 Sexual differentiation of the neural circuit for song in songbirds

12.2 Neuroanatomy and behavior are only loosely tethered together

12.3 Courtship and copulation in drosophila

13. Sexual differentiation of the primate brain

14. Sexual differentiation of the human brain

15. Imaging studies give insight into brain sex differences

16. Steroids and human brain development

16.1 Androgen insensitivity syndrome

16.2 Estrogen receptor mutation and aromatase deficiency

16.3 Congenital adrenal hyperplasia

17. The value of understanding the effect of sex on the developing brain

17.1 Maleness is an inherent risk factor for developmental disorders

17.2 Maternal immune activation is a risk factor for developmental psychiatric disorders

17.3 Connecting epigenetics and inflammation to explain male vulnerability

Bibliography

Classic references

Author biography.

Notes:

Part of: Colloquium digital library of life sciences.

Includes bibliographical references (pages 123-139).

Title from PDF title page (viewed on July 25, 2017).

Other Format:

Print version:

ISBN:

9781615047291

OCLC:

1002638484

Access Restriction:

Restricted for use by site license.