Ch. 4: Genetics, Development, and Plasticity

Cerebrovascular accident

Result of interrupted blood flow to the brain resulting from either a blood clot or a ruptured artery

Closed head injury

A result of a sharp blow to the head that does not puncture the brain

Collateral sprouts

Newly formed branches of an axon

Deafferent

To sever or lose the sensory nerve pathways connecting the peripheral nervous system to the central nervous system

Denervation supersensitivity

(receptor supersensitivity) increased sensitivity to neurotransmitters by a postsynaptic neuron after loss of input

Diaschisis

Decreased activity of surviving brain neurons after damage to other neurons

Edema

Accumulation of fluid

Hemorrhage

Type of stroke resulting from a ruptured artery

Ischemia

Type of stroke resulting from a blood clot or other obstruction in an artery

Phantom limb

A continuing sensation of an amputated body part

Stroke

A temporary loss of normal blood flow to a brain area

Tissue plasminogen activator (tPA)

Drug that breaks up blood clots

Altruistic behavior

An action that benefits someone other than the actor

Artificial selection

A process of selecting plants/animals for desire traits

Autosomal genes

All chromosomes other than X and Y

Chromosomes

Strands of genes

Deoxyribonucleuic acid (DNA)

The molecule that carries genetic information and instructions for building and maintaining and organism

Dizygotic twins

Fraternal twins formed from two separate eggs fertilized by two different sperm

Dominant gene

Gene that shows a strong effect in either the homozygous or heterozygous condition

Epigenetics

A field that deals with changes in gene expression without modification of the DNA sequence

Evolution

A change over generations in the frequencies of various genes in a population

Evolutionary psychology

Field that deals with how behaviors evolved

Fitness

The spreading of genes; number of copies of one’s genes that endure in later generations

Genes

Units of hereditary that maintain their structural identity from one generation to another

Group selection

Evolutionary selection favoring a gene because of its benefits to a group

Heritability

Estimate of the degree to which variation in a characteristic depends on genetic variations in a given population

Heterozygous

Having two unlike genes for a given trait

Histones

Proteins that bind DNA into a shape that resembles a string wound around a ball

Homozygous

Having two identical genes for a given characteristic

Kin selection

Selection for a gene that benefits the individual’s relatives

Lamarckian evolution

Discredited hypothesis that the use or disuse of some body part will increase or decrease its size in the next generation, known as “inheritance of acquired characteristics”

Monozygotic twins

Identical twins formed when one fertilized egg splits into two embryos

Mutation

A heritable change in a DNA molecule

Phenylketonuria (PKU)

A genetic disorder in which the body cannot properly break down the amino acide phenylalanine

Recessive gene

A gene that is expressed only when a person inherits two copies of it, one from each parent

Reciprocal altruism

Helping others who may be helpful in return

Ribonucleuic acid (RNA)

A single-strand chemical coded by DNA

S*x-limited genes

Genes present in both s*xes but expressed only in one s*x due to hormonal differences

S*x-linked genes

Genes located on the s*x chromosomes (usually the X chromosome)

Apoptosis

A programmed mechanism of cell death

Differentiates

The process by which cells become specialized for specific functions

Far transfer

Improvement of a skill due to practice at a dissimilar skill

Fetal alcohol syndrome

A condition resulting from prenatal exposure to alcohol and marked by hyperactivity, impulsiveness, decreased alterness, varying degrees of cognitive impairment, motor problems, heart defects, and facial abnormalities

Focal hand dystonia

(musician’s cramp) a disorder where one or more fingers is in constant contraction or where moving one finger independnetly of others is difficult

Migrate

Movement of brains neurons or glia

Myelination

Process by which glia produce the insulating fatty sheaths that accelerate transmission in many vetebrate axons

Nerve growth factor (NGF)

A protein that promotes the survival and growth of axons in sympathetic nervous system and certain axons in the brain

Neural darwinism

Principle of competition among axons

Neurotrophin

A chemical that promotes the survival and activity of neurons

Proliferation

Production of new cells

Stem cells

Undifferentiated cells that divide and produce daughter cells that develop more specialized properties

Synaptogenesis

Formation of synpases