Key Terms

1. Key Terms: Biological Bases of Behavior
1. All human (and animal) behavior is a product of biological structures and processes,
highly organized on multiple interconnected levels. Understanding these biological
precursors of behavior can lead to treatments for psychological disorders, such as drugs
that influence neurotransmitter function.
2. The nervous system is highly specialized and hierarchical in its structure, but
neuroplasticity gives the brain some flexibility to adapt its structure and function.
3. Though interconnected with and regulated by the nervous system, the endocrine system
produces effects on behavior in a distinct way: endocrine glands secrete hormones into
the bloodstream, allowing hormones to reach and interact directly with target organs.
4. Bio psychological researchers use a variety of imaging technologies to view the structure
and function of the brain, along with specialized research strategies that allow them to
learn more about the brain’s organization and the origin of psychological traits.
5. While many behaviors are learned as a result of experience within a particular
environment, the very capacity to learn such behaviors has a genetic basis, and such
capacities only persist because they contribute to the fitness of organisms.
6. Since the late nineteenth century, psychologists have investigated consciousness,
including the awareness of one’s self and environment, the ways consciousness can be
altered, and the various levels and states of consciousness.
7. Sleep cycles through multiple stages that vary in levels of neural activity, muscle control,
biological functions, and dreaming; sleep disorders cause disruptions to these processes.
8. Psychoactive drugs, including depressants, narcotics, stimulants, and hallucinogens,
affect brain chemistry to alter the perceptions and behavior of users; some psychoactive
drugs are used medicinally and/or recreationally, and some have a high potential for
abuse.
Key Terms: Biological Bases of Behavior
Neurons
 Neurons: The basic functional units of the nervous system; cells which contain
specialized structures to communicate signals.
 Soma/cell body: The part of a neuron that contains its nucleus and other standard cellular
structures.
 Dendrites: The multiple thin, treelike fibers that branch off from a neuron’s soma and
contain receptors to accept incoming signals from other neurons.
 Axon: A long, tubular structure in a neuron that transmits action potentials.
 Myelin sheath: A fatty substance that coats an axon, insulating it and enhancing its
ability to transmit action potentials.
 Terminal buttons: The branching structures at the ends of axons that release
neurotransmitters.
 Synapse: The small gap between the axon of a presynaptic neuron and the dendrites of a
postsynaptic neuron.

2.  Action potential: The electrical impulse sent along an axon when the dendrites of a
neuron are sufficiently excited.
 Neurotransmitter: A specialized chemical messenger which sends signals between
neurons.
 Excitatory: Describes a neurotransmitter that causes a postsynaptic neuron to propagate
more action potentials.
 Inhibitory: Describes a neurotransmitter that causes a postsynaptic neuron to propagate
fewer action potentials.
 Acetylcholine: A neurotransmitter involved in learning, memory, and muscle
contraction.
 Dopamine: A neurotransmitter involved in mood, movement, attention, and learning.
 Serotonin: A neurotransmitter that regulates sleep, mood, appetite, and body
temperature.
 Gamma amino butyric acid (GABA): The primary inhibitory neurotransmitter in the
nervous system.
 Norepinephrine: A neurotransmitter important in controlling alertness, wakefulness,
mood, and attention.
 Glutamate: The main excitatory neurotransmitter in the central nervous system;
important for learning and memory.
 Agonists: Drugs that mimic a particular neurotransmitter, activating the same receptors
that it does.
 Antagonists: Drugs that block a particular neurotransmitter from activating its receptors.
 Reuptake inhibitors: Drugs that prevent a neurotransmitter from being reabsorbed by
presynaptic axons, causing greater activation of postsynaptic receptors.
 Selective serotonin reuptake inhibitors (SSRIs): Drugs that prevent the reabsorption of
serotonin, leading to greater activation of serotonin receptors.
The Nervous System
 Nervous system: The organ system that governs the reception, processing, and
transmission of information throughout the body.
 Nerves: Fibrous bundles of neurons.
 Brain: The primary organ in the nervous system, which oversees most of its operations.
 Central nervous system(CNS): The brain and spinal cord.
 Hindbrain: The lowest segment of the brain, primarily involved in the regulation of
basic bodily functions and consisting of the cerebellum, medulla, pons, and reticular
formation.
 Cerebellum: Regulates motor coordination.
 Medulla: Controls autonomic responses, including breathing, heart rate, and blood
pressure.
 Pons: Transfers information between the cerebellum and other parts of the brain and
contributes to a wide variety of processes.
 Reticular formation: Contributes to attention and conscious state by filtering incoming
stimuli and selectively relaying information.

3.  Midbrain: The middle segment of the brain, involved with motor control, vision,
hearing, arousal, sleep, temperature regulation, and the transmission of sensory
information.
 Forebrain: The highest segment of the brain, consisting of the thalamus, hypothalamus,
hippocampus, amygdala, and cerebrum.
 Thalamus: Relays signals from other parts of the brain to the cerebral cortex and
regulates sleep, consciousness, appetite, and alertness.
 Hypothalamus: Regulates a variety of drives, including hunger, thirst, sexual arousal,
and temperature; the master regulator in the endocrine system.
 Amygdala: Involved with fear, aggression, and other emotions, as well as memory
consolidation.
 Hippocampus: Involved in the formation of long-term memories.
 Limbic system: Regulates emotions and drives; consists of the thalamus, hypothalamus,
amygdala, hippocampus, and other structures.
 Cerebrum: The largest part of the human brain; contains the cerebral cortex.
 Cerebral cortex: The wrinkled surface of the cerebrum, divided into four lobes and two
hemispheres.
 Lobes: Four specialized regions in the cerebral cortex.
 Frontal lobe: Controls voluntary movement and higher-order cognitive processes; at the
front of the brain.
 Parietal lobe: Integrates perceptions from different senses; at the top of the brain.
 Temporal lobe: Controls hearing and language; at both sides of the brain.
 Occipital lobe: Controls vision; at the back of the brain.
 Hemisphere: One of two symmetrical halves (left and right) of the brain, specialized for
particular functions.
 Lateralization: The localization of some functions in one of the two hemispheres.
 Wernicke’s area: The region in the temporal lobe of a person’s dominant hemisphere
that controls speech comprehension.
 Broca’s area: The region in the frontal lobe of a person’s dominant hemisphere that
controls speech production.
 Spinal cord: The long tube of nerves that connects the brain to most of the rest of the
body; protected by the vertebral column.
 Reflex: An automatic, involuntary response to a particular stimulus.
 Peripheral nervous system(PNS): All nerves outside of the brain and spinal cord.
 Somatic nervous system: Part of the PNS that controls skeletal muscles and their
voluntary movements.
 Autonomic nervous system: Part of the PNS that controls involuntary bodily functions.
 Sympathetic nervous system: Part of the autonomic nervous system activated during the
“fight or flight” response to stress.
 Parasympathetic nervous system: Part of the autonomic nervous system activated
during the “rest and digest” response to non-stressful situations.
 Neuroplasticity: The capacity of the brain to reorganize itself at a high level, such as
might happen in response to traumatic injury; it decreases with age.
 Synaptic plasticity: The ability for certain neural connections to be strengthened or
weakened over time, a process essential for memory and learning.
 Neurogenesis: The processes that create new neurons.

4. The Endocrine System
 Endocrine system: The system of glands that secrete hormones into the bloodstream in
order to maintain the body’s homeostasis.
 Homeostasis: A dynamic state of internal equilibrium within a changing external
environment.
 Hormones: Chemical messengers that travel through the bloodstream, interacting with
organs to stimulate or inhibit various biological processes.
 Glands: Endocrine organs that produce and secrete hormones.
 Pituitary gland: The primary gland in the endocrine system, regulated by the
hypothalamus; produces hormones that interact with the other endocrine glands.
 Thyroid gland: Produces and secretes hormones that regulate metabolism; found in the
neck.
 Adrenal glands: Produce and secrete stress hormones like cortisol and epinephrine
(adrenaline); found directly above the kidneys.
 Ovaries: Female gonads (sex glands) that secrete hormones like estrogen and
progesterone, which regulate the menstrual cycle and pregnancy.
 Testes: Male gonads (sex glands) that secrete androgens (male sex hormones) like
testosterone, which regulates sexual development and sexual desire.
Bio psychological Research
 Electroencephalograph (EEG): A device that uses electrodes on the scalp to detect and
record brain waves.
 MRI: Stands for “magnetic resonance imaging”; a technique that uses magnetic fields
and radio waves to produce high-resolution images of brain structure.
 Functional MRI (fMRI): An imaging technique similar to MRI, which measures blood
oxygen levels to determine brain function.
 PET scan: A technique that uses a radioactive dye injected into the bloodstream to detect
neurological activity.
 CT scan: A technique that uses X-rays to create 3-D images of brain structure.
 Traumatic brain injury (TBI): Damage to some part of the brain caused by an external
force; may impede cognitive, emotional, or behavioral functions.
 Corpus callosum: The bundle of nerves that serves as the primary connection between
the left and right cerebral hemispheres.
 Split-brain patients: Individuals with a severed corpus callosum; used in studies of brain
lateralization.
 Contralateral organization: The tendency of the left cerebral hemisphere to control and
perceive from the right side of the body, and vice versa.
 Twin study: A research design that investigates the traits of identical and fraternal twins
to determine the extent to which traits are genetically or environmentally controlled.
Hereditary, Environment, and Evolution

5.  Variation: The natural range of differences found among the traits of members of a
species.
 Inheritance: The transmission of various traits from one generation to the next. (Genes
are the units of inheritance.)
 Fitness: The tendency of a trait or organism to be well-suited to a particular
environment.
 Natural selection: The process by which fitter organisms are able to genetically
outcompete others of their species by living longer and having more offspring.
 Adaptations: Evolved traits that are well-suited to a particular environment.
 Sexual selection: The process by which organisms with more attractive traits are able to
genetically outcompete others of their species by having more offspring.
Types of Conscious States
 Consciousness: A state of being awake and aware of external stimuli and one’s own
mental activity.
 State of consciousness: The features of consciousness experienced by an individual at a
particular point in time.
 Altered state of consciousness: A temporary state that differs significantly from a
normal waking state; includes sleep, meditation, a coma, hypnosis, or the influence of
drugs.
 Conscious level: All of the things within one’s awareness at the present moment,
including information about one’s self and current environment.
 No conscious level: The body’s automatic biological processes, like breathing and
heartbeat, which are controlled by the brain but are generally outside of one’s active
awareness.
 Preconscious level: In Freud’s psychoanalytic theory, all of the unrepressed stored
memories, thoughts, and information that can be recalled and moved from the
unconscious to the conscious level in a matter of seconds.
 Unconscious level: In Freud’s psychoanalytic theory, the unconscious mind represents
the thoughts, desires, and urges that are actively repressed from consciousness and that
affect mental activity outside of active awareness.
 Subconscious level: Information beyond a person’s conscious awareness that affects
mental processes.
 Priming: When exposure to a stimulus beneath conscious awareness influences a
response to other stimuli.
 Mere-exposure effect: The preference for familiar stimuli over new stimuli, even when
exposure to the stimuli does not occur on a conscious level.
Sleepand Dreaming
 Non-rapid eye movement (NREM) sleep: A period of dreamless sleep divided into four
distinct, continuous stages.
 Rapid eye movement (REM) sleep: The period of sleep that is most associated with
dreaming.

6.  Hypnagogic hallucinations: Sensory phenomena, like visions and sounds that a sleeper
perceives in the transition between wakefulness and sleep.
 Sleepspindles: Bursts of neural activity that take place in stage 2 of NREM sleep and
may be important for memory consolidation.
 Slow wave sleep: Stages 3 and 4 of NREM sleep, the deepest stages of sleep, when
neural activity and brain waves are slowest.
 Paradoxical sleep: Another name for REM sleep, due to the contradictory way in which
the brain is active but the body is at rest.
 Manifest content: The actual events and imagery within a dream that, according to
Freud, serves to mask the unconscious thoughts and desires of the dreamer.
 Latent content: In Freudian terms, the unconscious thoughts and desires underlying the
manifest content of dreams.
 Activation-synthesis hypothesis: The theory that maintains dreams are the brain’s
interpretations of neural activity during REM sleep.
 Information-processing theory: The theory that maintains dreaming is a way for the
brain to deal with stress.
 Night terrors: A sleep disorder that causes the sleeper to wake from NREM sleep
suddenly with feelings of extreme fear, agitation, or dread.
 Insomnia: A sleep disorder marked by difficulty falling or staying asleep.
 Sleepapnea: A sleep disorder caused by breathing interruptions during sleep.
 Narcolepsy: A neurological sleep disorder characterized by irregular sleep patterns and
the inability to control and regulate sleep and wakefulness.
 Somnambulism: A sleep disorder also known as sleepwalking that occurs during slow
wave sleep and results in walking or performing other behaviors while asleep.
Psychoactive Drugs
 Psychoactive drugs: Drugs that affect the chemical and physical functioning of the
brain, altering the perception and behavior of the user.
 Depressants: Drugs that slow down neural activity.
 Narcotics: Drugs that dull the senses and relieve pain, also called opioids.
 Stimulants: Drugs that excite neural activity and speed up body functions, including
heart and respiration rates; often used to relieve fatigue and increase alertness.
 Hallucinogens: Drugs that alter mood, distort perceptions, and evoke sensory images in
the absence of sensory input.
Important Contributors
 Alois Alzheimer: Discovered Alzheimer’s disease, named after him, when he performed
an autopsy on the brain of a 55-year-old woman who had died after many years of
progressive mental decline.
 Thomas Bouchard: American psychologist best known for studying identical twins
separated at birth to determine the effects of genetics and environment on a variety of
traits.
 Paul Broca: A French scientist who investigated speech disorders. The region of the
cerebrum responsible for speech production was named after him (Broca’s area), as was
an associated speech disorder (Broca’s aphasia, also known as expressive aphasia).

7.  Charles Darwin: Developed the idea of evolution through natural selection, which he
used to explain the origin of species.
 Sigmund Freud: The founder of psychoanalysis. His approach to therapy included
dream interpretation, which Freud believed could reveal insights about the unconscious
mind.
 Francis Galton: An English scientist who founded the field of behavioral genetics,
popularized the phrase “nature versus nurture,” and was the first to apply statistical
methods to study heredity and intelligence.
 Michael Gazzaniga: An American cognitive neuroscientist, best known for his research
with Sperry on split-brain patients.
 William James: Founder of functionalism who maintained that psychology should aim
to understand how consciousness helps organisms adapt to their environments.
 Roger Sperry: An American neuropsychologist who conducted groundbreaking research
with Gazzaniga on split-brain patients, which helped to improve understanding of brain
lateralization.
 Carl Wernicke: A German scientist who studied speech disorders. The region of the
cerebrum responsible for speech comprehension was named after him (Wernicke’s area),
as was an associated speech disorder (Wernicke’s aphasia, also known as receptive
aphasia).
Wilhelm Wundt: Founder of structuralism; used the technique of introspection to investigate
structures of consciousness.