Brain Structures and their Functions

The Endocrine System

Endocrine System the body’s “slow”

chemical communication system

a set of glands that secrete hormones into the bloodstream

Neural and Hormonal Systems

Hormones chemical messengers, mostly those manufactured by the

endocrine glands, that are produced in one tissue and affect another

Adrenal [ah-DREEN-el] Glands a pair of endocrine glands just above the kidneys secrete the hormones epinephrine (adrenaline) and

norepinephrine (noradrenaline), which help to arouse the body in times of stress

Pituitary Gland under the influence of the hypothalamus, the pituitary

regulates growth and controls other endocrine glands

Genes and Behavior: The Interdisciplinary Field of Behavioral Genetics

• Behavioral genetics = the study of the influence of genetic factors on behavioral traits

• Basic terminology:• Chromosomes – strands of DNA carrying genetic

information– Human cells contain 46 chromosomes in pairs (sex-

cells – 23 single)– Each chromosome – thousands of genes, also in pairs

• Dominant, recessive• Homozygous, heterozygous• Genotype/Phenotype and Polygenic Inheritance

Research Methods in Behavioral Genetics

• Family studies – does it run in the family?• Twin studies – compare resemblance of

identical (monozygotic) and fraternal (dizygotic) twins on a trait

• Adoption studies – examine resemblance between adopted children and their biological and adoptive parents

Modern Approaches to the Nature vs. Nurture Debate

• Molecular Genetics = the study of the biochemical bases of genetic inheritance– Genetic mapping – locating specific genes

- The Human Genome Project• Behavioral Genetics– The interactionist model– Richard Rose (1995) – “We inherit

dispositions, not destinies.”

Parental Investment and Mating Systems - sociobiology

• Polygyny – high female, low male – based on a study by Buss (1994) found in 84 % of human cultures

• Polyandry – high male, low female – rare but examples have been found for example in the Pahari of Nepal and India, and Tibet and other limited places in the world. The system in Tibet was based on class and land considerations.http://www.case.edu/affil/tibet/booksAndPapers/pahari.html

• Monogamy – shared parental investment but not always equal. There are few exclusively monogamous species – 15 % of human cultures (Buss, 1994)

• Polygynadry – group parental investment and very rare – in chimpanzees mating is promiscuous for males and females

• Incest – universal taboo – increased genetic diversity

Figures 3.32 & 3.33 – brain asymmetry and speech localization – use of Wadi technique and TMS