Unit 2: Biological Bases of Behavior (AP REVIEW)

Unit 2 in AP CLASSROOM

Broca's area

The part of the left frontal lobe associated with loss of the ability to speak, known as expressive aphasia.

Wernicke's area

Another brain area involved in understanding language, located in the left temporal lobe.

Lesions

Precise destruction of brain tissue, enabling the study of loss of function resulting from surgical removal, cutting of neural connections, or destruction by chemical applications.

Brain lateralization

The specialization of functions in the left and right hemispheres of the brain.

Computerized axial tomography (CAT or CT)

A technique that creates a computerized image of the brain using X-rays passed through various angles, showing two-dimensional "slices" that reveal the extent of a lesion.

Magnetic resonance imaging (MRI)

A technique that uses a magnetic field and pulses of radio waves to create an image of the brain, based on the density of the tissue.

EEG (electroencephalogram)

An amplified tracing of brain activity produced when electrodes transmit signals about the brain's electrical activity to a machine.

PET (positron emission tomography)

A technique that produces color computer graphics based on the amount of metabolic activity in the imaged brain region.

fMRI (functional MRI)

A technique that shows the brain at work at a high resolution by detecting changes in oxygen in the blood of an active brain area.

MSI (magnetic source image)

An image produced by magnetoencephalography (MEG scan), which detects the slight magnetic field caused by electric potentials in the brain.

Central nervous system

Consists of the brain and spinal cord.

Peripheral nervous system

Includes the somatic nervous system and the autonomic nervous system.

Somatic nervous system

Has motor neurons that stimulate voluntary skeletal muscle.

Autonomic nervous system

Has motor neurons that stimulate involuntary smooth and heart muscle.

Plasticity

The brain's ability to reorganize and take over functions if a specific region is damaged.

Neuron

The basic unit of structure and function of the nervous system.

Glial cells

Cells that guide the growth of neurons, provide nutrition and insulation, and help get rid of waste.

Neurotransmitters

Chemicals stored in synaptic vesicles that transmit signals between neurons.

Resting potential

The neuron's more negative state inside the cell membrane relative to the outside.

Action potential

A rapid change in potential across the membrane when the neuron is sufficiently stimulated.

All-or-none principle

The principle that the strength of an action potential is constant whenever it occurs.

Saltatory conduction

The conduction of depolarizations along myelinated axons, jumping from node to node.

Excitatory neurotransmitters

Neurotransmitters that cause the neuron on the other side of the synapse to generate an action potential.

Inhibitory neurotransmitters

Neurotransmitters that reduce or prevent neural impulses.

Reflex

Involves impulse conduction over a few neurons, following a reflex arc.

Endocrine system

Consists of glands that secrete hormones into the blood.

Hormones

Chemical messengers that travel to target organs and bind to specific receptors.

Pineal gland

Endocrine gland in the brain that produces melatonin, which helps regulate circadian rhythms.

Hypothalamus

Portion of the brain that acts as an endocrine gland and produces hormones that stimulate or inhibit secretion by the pituitary gland.

Pituitary gland

Endocrine gland in the brain that produces stimulating hormones for other glands, such as TSH, ACTH, FSH, ADH, and HGH.

Thyroid gland

Endocrine gland in the neck that produces thyroxine, which stimulates and maintains metabolic activities.

Parathyroids

Endocrine glands in the neck that produce parathyroid hormone, which helps maintain calcium ion levels in the blood.

Adrenal glands

Glands located atop the kidneys that produce hormones involved in various functions, such as stress response and metabolism.

Endocrine glands

Glands located on top of the kidneys that release hormones into the bloodstream.

Pancreas

A gland near the stomach that secretes the hormones insulin and glucagon, which regulate blood sugar levels.

Ovaries and Testes

Gonads in females and males, respectively, that produce hormones necessary for reproduction and development of secondary sex characteristics.

Nature-nurture controversy

The debate about the extent to which heredity and the environment influence behavior.

Evolutionary psychologists

Researchers who study how natural selection has favored behaviors that contribute to survival and the spread of genes.

Behavioral geneticists

Scientists who study the role of genes and the environment in mental abilities, personality traits, and other individual differences.

Identical twins

Twins who share all of the same genes because they develop from the same fertilized egg.

Fraternal twins

Twins who share about half of the same genes because they develop from two different fertilized eggs.

Heritability

The proportion of variation among individuals in a population that is due to genetic causes.

Gene

A segment of DNA on a chromosome that determines a specific trait.

Chromosomes

Structures that carry information stored in genes to new cells during reproduction.

Genotype

The genetic makeup of an individual for a particular trait.

Phenotype

The expression of genes, resulting in observable traits.

Dominant gene

The expressed gene when genes are different; the hidden gene is called the recessive gene.

Turner syndrome

A condition in which individuals have only one X sex chromosome (XO).

Klinefelter's syndrome

A condition that arises from an XXY zygote.

Down syndrome

A genetic disorder caused by the presence of three copies of chromosome 21.

Tay-Sachs syndrome

A genetic disorder that produces progressive loss of nervous function and death in infants.

Albinism

A condition characterized by a failure to synthesize or store pigment, resulting in lack of coloration in the skin, hair, and eyes.

Phenylketonuria (PKU)

A genetic disorder that results in severe brain damage unless the baby is fed a special diet low in phenylalanine.

Huntington's disease

A degenerative disorder of the nervous system caused by a dominant gene defect.

Alzheimer's disease

A form of dementia that has been attributed to a gene on chromosome 21.

Preconscious

The level of consciousness that contains feelings and memories that can be easily brought into conscious awareness.

Nonconscious

The level of consciousness devoted to processes inaccessible to conscious awareness, such as physiological functions and lower-level processing of sensations.

Unconscious

The level of consciousness that includes unacceptable feelings, wishes, and thoughts not directly available to conscious awareness.

Dual processing

The processing of information on conscious and unconscious levels simultaneously.

Unconsciousness

A state characterized by loss of responsiveness to the environment, often caused by disease, trauma, or anesthesia.

Hypothalamus

A brain structure that regulates various bodily functions, including sleep-wake cycles.

Circadian rhythm

A natural, internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours.

Sleep

A complex combination of states of consciousness, each with its own level of awareness, responsiveness, and physiological arousal.

Electroencephalograms (EEGs)

Recordings of brain activity using electrodes placed on the surface of the skull.

Hypnagogic state

A relaxed state in which individuals fail to respond to outside stimuli and enter the first stage of sleep, Non-REM-1.

NREM-1

The first stage of non-rapid eye movement (NREM) sleep, characterized by theta waves on EEGs.

NREM-2

The second stage of NREM sleep, characterized by high-frequency bursts of brain activity (sleep spindles) and K complexes on EEGs.

NREM-3

The third stage of NREM sleep, characterized by very high amplitude and very low-frequency delta waves on EEGs.

REM sleep

A stage of sleep characterized by rapid eye movements and heightened brain activity, often associated with dreaming.

Nightmares

Frightening dreams that occur during REM sleep.

Lucid dreaming

The ability to be aware of and direct one's dreams.

Manifest content

The remembered story line of a dream, according to Freud.

Latent content

The underlying meaning of a dream, according to Freud.

Activation-synthesis theory

A theory of dreams proposed by McCarley and Hobson, suggesting that dreams are the brain's attempt to make sense of random neural activity during sleep.

Pons

A brain structure that generates bursts of action potentials to the forebrain during sleep.

Insomnia

The inability to fall asleep and/or stay asleep.

Narcolepsy

A condition in which an awake person suddenly and uncontrollably falls asleep, often directly into REM sleep.

Sleep apnea

A sleep disorder characterized by temporary cessations of breathing during sleep.

Night terrors

Childhood sleep disruptions characterized by bloodcurdling screams and intense fear, occurring during deep NREM-3 sleep.

Sleepwalking

A childhood sleep disruption characterized by walking or carrying out complex activities during deep NREM-3 sleep.

Hypnosis

An altered state of consciousness characterized by deep relaxation and heightened suggestibility.

Dissociation theory

A theory of hypnosis suggesting that hypnotized individuals experience two or more streams of consciousness cut off from each other.

Meditation

A set of techniques used to focus concentration away from thoughts and feelings, creating calmness and inner peace.

Psychoactive drugs

Chemicals that can alter perception, thinking, behavior, and mood by passing through the blood-brain barrier into the brain.

Psychological dependence

A strong desire to achieve the drugged state despite adverse effects.

Tolerance

Decreasing responsivity to a drug, requiring higher doses to achieve the same effect.

Physiological dependence

Addiction characterized by changes in brain chemistry that necessitate taking the drug to prevent withdrawal symptoms.

Withdrawal symptoms

Symptoms that occur when a drug is discontinued, including intense craving and opposite effects of the drug.

Depressants

Psychoactive drugs that reduce central nervous system activity and induce relaxation, such as sedatives and alcohol.

Narcotics

Analgesics that work by depressing the central nervous system and can also depress the respiratory system.

Stimulants

Psychoactive drugs that activate motivational centers and reduce activity in inhibitory centers of the central nervous system, such as serotonin, dopamine, and norepinephrine.

Hallucinogens

Psychoactive drugs that alter moods, distort perceptions, and evoke sensory images in the absence of sensory input.