Unit 2: Biological Approach to Human Behavior

holistic viewpoint

This means taking multiple factors (or the entire human being) into account when studying behavior.

reductionist viewpoint

This means to study behavior scientifically, we need to isolate certain factors or behaviors and study them individually.

Localization of function

... the idea that every behavior is associated with a specific brain region or area.

The Nervous System

A system of neurons that perform the function of communication throughout the body.

The central nervous system

This systems consists of the spinal cord and the brain.

Neuroplasticity

The ability of the brain to change by the development and destruction of synaptic connections between neurons or neural networks. This could be caused by genetic or environmental factors.

synaptic pruning

the elimination of neurons as the result of nonuse or lack of stimulation

Neuron

Nerve cells that send messages all over your body to allow you to do everything from breathing to talking, eating, walking, and thinking.

Synapse (synaptic cleft or synaptic gap)

The places where neurons connect and communicate with each other.

Neurotransmitter

chemical messengers that cross the synaptic gaps between neurons

Excitatory Neurotransmitter

Neurotransmitter that allows the events or impulses to cross a synapse by triggering an action potential in the post-synaptic neuron.

Agonist

A drug which increases the effect of a neurotransmitter.

Inhibitory Neurotransmitter

Neurotransmitter that prevents or stops the events or impulses by stopping an action potential in the post-synaptic neuron.

Antagonist

A drug which reduces the effect or a neurotransmitter.

dendritic branching

One kind of change to a neuron's structure that increases its surface area and thus available sites for new synaptic connections to new neurons.

hormones

Chemicals released by specific glands in the endocrine system that regulate changes in the body and move in blood. Some, like adrenaline, can act also like neurotransmitters.

pheromones

Chemical signals that trigger specific behaviors or physiological responses between members of the same species. Though there is increasing evidence that these could have an effect on human behavior, none of these are conclusive or scientifically backed.

genes

Made up of DNA which provides the structure and function of the human body.

gene regulation

The ability of genes to be switched on and off.

gene expression

conversion of the information encoded in a gene first into messenger RNA and then to a protein to carry out the gene function.

Vomeralnasal Organ (VNO)

Though nonexistent or inactive in most humans, this organ is responsible in most animals for receiving pheromones.

Cortex

The layer of neurons covering the brain on the outside. Largest part of the human brain associated with abstract thought or voluntary action.

Frontal Lobe

Lobe associated with reasoning, planning, thinking, decision making, voluntary action, complex emotion

Parietal Lobe

Lobe associated with movement, orientation, perception, and recognition.

Occipital Lobe

Lobe associated with visual processing.

Temporal Lobe

Lobe associated with processing auditory information, memory, and speech.

Broca's area

Controls speech and lanuage expression- an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech. Damage here is called aphasia.

Wernicke's area

a brain area involved primarily in language comprehension and expression; usually in the left temporal lobe

Corpus Callosum

A neural network structure that connects the two hemispheres of the brain, covered in large quantities of myelin.

Thalamus

Associated with most sensory functions, the nerves from almost all sensory organs reash this area as a final processing headquarters before they are connected to the cortex.

Hypothalamus

Associated with functions such as emotion, thirst, and hunger.

Amygdala

Associated with memory, emotion, and fear.

Hippocampus

Associated with functions such as learning, memory, and transferring short-term memory to a more permanent store, spacial orientation, etc.

Cortical Remapping

The phenomenon when one brain area takes over the function of another brain area, for example, due to injury.

SSRI

Selective Serotonin Reuptake Inhibitor - blocks the reabsorption of the neurotransmitter serotonin

placebo

A harmless substance with no effect.

alleles

Different forms of a gene, can be dominant or recessive.

genotype

The set of traits that is coded into your DNA - the plan that is in your genes.

phenotype

Observable and unobservable characteristics including traits and behavior - the implementation of what is in your genes.

epigenetics

The study of how environmental factors and behaviors can alter the way genes work without changing the DNA sequence.

Evolution

The idea that all species are related and change over time from generation to generation.

Natural Selection

a process that explains how organisms evolve over time by adapting to their environment - ideal survival traits develop over time, where as traits that no longer benefit no longer transfer to the next generation.

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue; allows us to see structures within the brain.

fMRI (functional MRI)

A technique for revealing bloodflow and, therefore, brain activity and brain functions by comparing successive MRI scans.

PET (Positron Emission Tomography)

a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task

EEG (electroencephalography)

the recording of brain activity by the detection of electrical activity in specific areas on the surface of the cortex by several surface electrodes placed on a person's scalp. Brain activity is recorded as waves.

CAT (computerized axial tomography)

uses a rotating X-ray to create 2D images of brain structure only.

VBM (Voxel-based morphometry)

A technique using an MRI that involves measuring regional VOLUME differences in gray and white matter concentrations

differential fitness

Different traits confer different rates of survival and reproduction in evolution

kinship studies

Scientific studies in which researchers assess hereditary influence by examining blood relatives (including twins, siblings, parent/child) to see how much they resemble each other on a specific trait.

Nature versus nurture

A debate surrounding the relative importance of heredity (nature) and environment (nurture) in determining behavior: twin studies help with this.

adoption studies

Research studies that assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents.

Methylation of DNA

inactivates genes or altered gene activity

Bateson's cube

is a cost-benefit analysis of animal research which considers the degree of animal suffering, the quality of research, and the potential medical benefit to humans

reduction, refinement, replacement

The three R's of animal research

genetic drift

A change in the allele frequency (gene pool) of a population as a result of chance rather than natural selection.

action potential

a neural impulse; a brief electrical charge that travels down an axon if it reaches the threshold of activation

reuptake

process by which neurotransmitters are taken back into the synaptic vesicles for reuse

Acetylcholine (ACh)

a neurotransmitter involved in learning, memory and muscle movement

Dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

Oxytocin

A hormone released by the posterior pituitary that may help in bonding in humans and animals, interpersonal trust, cooperation, and fidelity

BOLD

blood oxygen level-dependent contrast; the signal measured in fMRI that relates to the concentration of deoxyhemoglobin in the blood to view brain function

Cortisol

stress hormone released by the adrenal cortex

Falconer Model

The model assumes that traits are the accumulation of three independent factors: genetic inheritance, shared environment, and individual environment.

niche-picking

tendency to actively choose environments that complement our heredity

monozygotic(MZ) twins

twins who are genetically identical

dizygotic(DZ) twins

twins formed when a woman produces 2 ova or eggs, which are fertilized by 2 sperm; fraternal twins, born at the same time but not identical