Biological Bases of Behavior: Vocab Terms

Vocabulary from Myer's Psychology for the AP Course (III), CH. 3 Biological Bases of Behavior

Neuron

A nerve cell; the basic building block of the nervous system.

Cell body

The part of a neuron that contains the nucleus; the cell’s life support center.

Dendrites

A neuron’s bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body

Axon

The neuron extension that passes messages through its branches to other neurons or to muscles or glands.

Myelin sheath

A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next.

Glial cells

Cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory.

Action potential

A neural impulse; a brief electrical charge that travels down an axon.

Threshold

The level of stimulation required to trigger a neural impulse.

Refractory period

In neural processing, a brief resting pause occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.

All-or-none response

A neuron’s reaction of either fighting (with a full-strength response) or not firing.

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, they travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

Reuptake

A neurotransmitter’s reabsorption by the sending neuron.

Agonist

A molecule that increases a neurotransmitter’s action.

Antagonist

A molecule that inhibits or blocks a neurotransmitter’s action.

Nervous system

The body’s speedy, electrochemical communication network, consisting of all the nerve cells (neurons) of the peripheral and central nervous system.

Central nervous system (CNS)

Consists of the brain and spinal cord; the body’s decision maker and information processing system

Peripheral nervous system (PNS)

Consists of the sensory and motor neurons that connect the CNS to the rest of the body; responsible for gathering information and transmitting CNS decisions to other body parts through nerves.

Nerves

Bundled axons that form neural cables connecting the CNS with muscles, glands, and sense organs.

Sensory (afferent) neurons

Neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord.

Motor (efferent) neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

Interneurons

Neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs.

Somatic nervous system

The division of the PNS that controls the body’s skeletal muscles.

Autonomic nervous system

The part of the PNS that controls glands and the muscles of the internal organs. Its sympathetic division arouses; its parasympathetic division calms.

Sympathetic nervous system

The division of the autonomic nervous system that arouses the body, mobilizing its energy.

Parasympathetic nervous system

The division of the autonomic nervous system that calms the body, conserving its energy.

Endocrine system

The body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

Hormones

Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.

Adrenal glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.

Pituitary gland

The endocrine system’s most influential gland. Under the influence of the hypothalamus, it regulates growth and controls other endocrine glands.

Lesion

Tissue destruction. A naturally or experimentally caused destruction of brain tissue.

EEG (electroencephalogram)

An amplified recording of the waves of electrical activity sweeping across the brain’s surface. These waves are measured by electrodes placed on the scalp.

MEG (magnetoencephalography)

A brain imaging technique that measures magnetic fields from the brain’s natural electrical activity.

CT (computed tomography scan, or CAT) scan

A series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain’s structure.

PET (positron emissions tomography) scan

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

MRI (magnetic resonance imaging)

A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. Shows brain activity.

fMRI (functional MRI)

A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. Shows brain function as well as structure.

Brainstem

The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the brain; responsible for automatic survival functions.

Medulla

The base of the brainstem; controls heartbeat and breathing

Thalamus

The brain’s sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Reticular formation

A nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal.

Cerebellum

The “little brain” at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.

Hypothalamus

Directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Cerebral cortex

The intricate fabrics of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control and information-processing center.

Frontal lobes

The portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.

Parietal lobes

The portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body positions.

Occipital lobes

The portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields.

Temporal lobes

The portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear.

Motor cortex

An area located at the back of the frontal lobes, running across the top of the brain from ear to ear. Controls voluntary bodily movements. Stimulation to specific parts of the cortex, causes its respective, lateralized, specific body parts to move.

Somatosensory cortex

An area at the front of the parietal lobes. Receives, registers, and processes body touch and movement sensations. Stimulation can cause feelings of being touched. 

Association areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.

Plasticity

The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.

Corpus callosum

The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Spit brain

A condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers connecting them.

Consciousness

Our subjective awareness of ourselves and our environment.

Cognitive neuroscience

The interdisciplinary study of the brain activity linked with cognition (including, perception, thinking, memory, and language).

Dual processing

The principle that information is often simultaneously processed on separate conscious and unconscious tracks.

Blindsight

A condition in which a person can respond to a visual stimulus without consciously experiencing it.

Parallel processing

Processing many aspects of a problem simultaneously; generally used to process well-learned information or to solve easy problems.

Sequential processing

Processing one aspect of a problem at a time; generally used to process new information or to solve difficult problems

Behavior genetics

The study of the relative power and limits of genetic and environmental influences on behavior.

Heredity

The genetic transfer of characteristics from parents to offspring.

Environmental factor

Every nongenetic influence, from prenatal nutrition to the people and things around us.

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

DNA (deoxyribonucleic acid)

A complex molecule containing the genetic information that makes up the chromosomes.

Genes

The biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins.

Genome

The complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes.

Monozygotic (identical) twins

Develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

Dizygotic (fraternal) twins

Develop from separate fertilized eggs. They are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment.

Heritability

The proportion of variation among individuals in a group that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied.

Interaction

The interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).

Molecular genetics

The subfield of biology that studies the molecular structure and function of genes.

Molecular behavior genetics

The study of how the structure and function of genes interact with our environment to influence beahvior.

Epigenetics

The study of environmental influences on gene expression that occur without a DNA change.

Evolutionary psychology

The study of the evolution of behavior and the mind, using principles of natural selection.

Natural selection

The principle that inherited traits that better enable an organism to survive and reproduce in a particular environment will (in competition with other trait variations) most likely be passed on to succeeding generations.

Mutation

A random error in gene replication that leads to a change.

Social script

A culturally modeled guide for how to act in various situations.

Paul Broca

A French physician, anatomist, and anthropologist. Most well known for his research in the area of the brain responsible for speech production in the frontal lobe. 

Carl Wernicke

A German physician, anatomist, psychiatrist, and neuropathologist. Most well known for his research in Wernicke’s area, the area of the brain responsible for speech comprehension in the temporal lobe.

Roger Sperry

An American neuropsychologist, neurobiologist, and cognitive neuroscientist. Most well-known for severing the cerebral hemispheres of cats and monkeys, he then won the 1981 Nobel Prize in Physiology and Medicine for his exploration of the special, distinct functions of each hemisphere of the brain.

Michael Gazzaniga

An American cognitive neuroscientist most well known for his research in split-brain patients and cerebral lateralization.

Charles Darwin

An English naturalist, geologist, and biologist. Most well-known for the theory of evolution and natural selection. Evolutionary psychology is founded upon his works

Epigenetic marks

Organic methyl molecules attached to parts of DNA strands that regulate the activation or silencing of genes.

Acetylcholine (ACh)

Neurotransmitter that enables muscle actions, learning, and memory. With Alzheimer’s disease, neurons producing this neurotransmitter deteriorate.

Dopamine

Neurotransmitter that influences movement, learning attention, and emotion. Oversupply linked to schizophrenia. Undersupply linked to tremors and decreased mobility in Parkinson’s disease

Serotonin

Neurotransmitter that affects mood, hunger, sleep, and arousal. Undersupply linked to depression. Some drugs that raise levels are used to treat depression

Norepinephrine

Neurotransmitter that helps control alertness and arousal. Undersupply can depress mood

GABA (gamma-aminobutyric acid)

A major inhibitory neurotransmitter that helps calm the body. Undersupply linked to seizures, tremors, and insomnia

Glutamate

A major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain, producing migraines or seizures (which is why some people avoid monosodium glutamate (MSG) in food)

Endorphins

Neurotransmitters that influence the perception of pain or pleasure. Oversupply with opiate drugs can suppress the body’s natural endorphin supply

Limbic system

The brain region located below the cerebral hemispheres that’s responsible for emotions, motivation, and memory. It includes the amygdala, hippocampus, and hypothalamus.

Visual cortex

Part of the brain responsible for processing visual information. Located in the occipital lobe, it receives signals from the eyes and helps us perceive color, shape, movement, and depth.

Auditory cortex

A brain region that processes sound information. It's located in the temporal lobe and is responsible for identifying pitch, loudness, and location of sounds.

Broca's area

A brain region that controls speech production. It's located in the left frontal lobe and is responsible for the coordination of movements necessary for speech.

Wenicke’s area

Region of the brain responsible for language comprehension and expression. Damage to this area can cause receptive and expressive aphasia. Located in the posterior part of the left temporal lobe.

Neurogenesis

The process by which the brain forms new neurons.

Split-brain

A condition where the corpus callosum is severed, resulting in limited communication between the two hemispheres of the brain.