Myer's AP Psychology Chapter 3: Biological Bases of Behavior

fMRI (functional MRI)

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

MRI (magnetic resonance imaging)

A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. They scans show brain anatomy.

electroencephalogram (EEG)

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

motor cortex

An area at the rear of the frontal lobes that controls voluntary movements.

glial cells (glia)

Cells in the nervous system that support, nourish, and protect neurons.

medulla

The base of the brainstem; controls heartbeat and breathing.

endocrine system

The body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream.

central nervous system (CNS)

The brain and spinal cord.

chromosomes

Threadlike structures made of DNA molecules that contain the genes.

lesion

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

amygdala

Two lima bean-sized neural clusters in the limbic system; linked to emotion.

action potential

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

reuptake

A neurotransmitter's reabsorption by the sending neuron.

sensory cortex

Area at the front of the parietal lobes that registers and processes body touch and movement sensations.

parasympathetic nervous system

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

somatic nervous system

The division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system.

pituitary gland

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

axon

The extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands.

identical twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

fraternal twins

Twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment.

evolutionary psychology

The study of the roots of behavior and mental processes using the principles of natural selection.

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.

mutation

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

CT (computed tomography) scan

A series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body. Also called CAT scan.

reflex

A simple, automatic response to a sensory stimulus, such as the knee-jerk response.

PET (positron emission tomography) scan

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

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.

nerves

Bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sense organs.

synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

corpus callosum

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

threshold

The level of stimulation required to trigger a neural impulse.

endorphins

"Morphine within"—natural, opiatelike neurotransmitters linked to pain control and to pleasure.

biological psychology

A branch of psychology concerned with the links between biology and behavior.

DNA (deoxyribonucleic acid)

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

split brain

A condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.

myelin sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

neuron

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

reticular formation

A nerve network in the brainstem that plays an important role in controlling arousal.

hypothalamus

A neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

hormones

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

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.

Broca's area

Controls language expression—an area, usually in the left frontal lobe, that directs the muscle movements involved in speech.

Wernicke's area

Controls language reception—a brain area involved in language comprehension and expression; usually in the left temporal lobe.

limbic system

Doughnut-shaped neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

environment

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

aphasia

Impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).

sensory neurons

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

motor 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 that communicate internally and intervene between the sensory inputs and motor outputs.

consciousness

Our awareness of ourselves and our environment.

occipital lobes

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

parietal lobes

Portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

frontal lobes

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

temporal lobes

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

cerebellum

The "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance.

genes

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

nervous system

The body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

plasticity

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

thalamus

The brain's sensory switchboard, 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.

dendrite

The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

genome

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

sympathetic nervous system

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

neurogenesis

The formation of new neurons.

cognitive neuroscience

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

interaction

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

cerebral cortex

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

brainstem

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

autonomic nervous system

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

dual processing

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

natural selection

The principle that, among the range of inherited trait variations, those contributing to reproduction and survival will most likely be passed on to succeeding generations.

heritability

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

peripheral nervous system (PNS)

The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

behavior genetics

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

molecular genetics

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