1.
absolute refractory period: the minimum length of time after an action potential during which another action potential cannot begin
2.
acetylcholine (Ach): the only transmitter between motor neurons and voluntary muscles, found throughout the nervous system
3.
action potential: a very brief shift in a neuron's electrical charge that travels along an axon; a brief electric impulse by which information is transmitted along the axon of a neuron
4.
adaptation: an inherited characteristic that increased in a population (through natural selection) because it helped solve a problem of survival or reproduction during the time it emerged
5.
adoption studies: assesses hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents
6.
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
7.
afferent nerve fibers: axons that carry information inward to the central nervous system (CNS) from the periphery of the body
8.
agonist: a chemical that mimics the action of a neurotransmitter
9.
all-or-nothing law: The principle that either a neuron is sufficiently stimulated and an action potential occurs or a neuron is not sufficiently stimulated and an action potential does not occur.
10.
amygdala: an almond-shaped part of the limbic system; plays a central role in the learning of fear responses and the processing of other basic emotional responses
11.
antagonist: a chemical that opposes the action of a neurotransmitter
12.
aphasia: impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding)
13.
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
14.
autonomic nervous system: part of the PNS made up of nerves that connect to the heart, blood vessels, smooth muscles, and glands; its sympathetic division arouses and its parasympathetic division calms
15.
axon: a long, thin fiber that transmits signals away from the soma to other neurons or to muscles or to glands; convey information out
16.
brainstem: the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions
17.
Broca's area: an area in the left side of the frontal lobe which plays an important role in the production of speech
18.
central nervous system (CNS): consists of the brain and the spinal cord; protected by meninges (enclosing sheaths) and bathed in CSF
19.
cerebellum ("little brain"): a large and deeply folded structure located adjacent to back surface of the brainstem; it is critical to the coordination of movement and to the sense of equilibrium (physical balance)
20.
cerebral cortex: the convoluted, wrinkled surface of the cerebrum, also the outer layer of the brain; regulates most complex behavior, including sensations, motor control, and higher mental processes such as decision making
21.
cerebral hemispheres: the nearly symmetrical right and left halves of the cerebrum, separated by a longitudinal fissure running from the front to the back of the brain
22.
cerebrospinal fluid (CSF): nourishes the brain and provides a protective cushion for it, found in ventricles in the brain
23.
cerebrum: the seat of complex thought
24.
chromosomes: strands of DNA [deoxyribonucleic acid] molecules that carry genetic information
25.
cognitive neuroscience: the interdisciplinary study of the brain activity linked with cognition (including perception, memory, thinking and language)
26.
corpus callosum: the structure, consisting of a thick band of fibers, that connects the two cerebral hemispheres
27.
critical period: a limited time span in the development of an organism when it is optimal for certain capacities to emerge because the organism is especially responsive to certain experiences
28.
CT (computerized tomography) scan: a computer enhanced X-ray of brain structure, creates an image of a horizontal slice of the brain
29.
dendrites: the parts of a neuron that are specialized to receive information; bring information in
30.
dominant gene: the gene that is expressed when paired genes are different (heterozygous)
31.
dopamine hypothesis: asserts that abnormalities in activity at dopamine synapses play a crucial role in the development of schizophrenia
32.
dual processing: the principle that information is often simultaneously processed on separate conscious and unconscious tracks
33.
efferent nerve fibers: axons that carry information outward from the central nervous system (CNS) to the periphery of the body
34.
electrical stimulation of the brain (ESB): sending a weak electric current into a brain structure to stimulate (activate) it
35.
electroencephalograph (EEG): a device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp
36.
endocrine system: the body's "slow" chemical communication system; glands that secrete chemicals into the bloodstream that help control bodily functioning
37.
endorphins: internally produced chemicals that resemble opiates in structure and effects; reduce the perception of pain
38.
family studies: researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait
39.
fitness: the reproductive success (number of descendants) of an individual organism relative to the average reproductive success in the population
40.
forebrain: the largest and most complex region of the brain, includes three structures at the core of the forebrain (the thalamus, hypothalamus, and limbic system) and the cerebrum
41.
fraternal (dizygotic) twins: results when two eggs are fertilized simultaneously by different sperm cells, forming two separate zygotes
42.
frontal lobe: contains the primary motor cortex, the principal areas devoted to control of the movement of muscles
43.
functional magnetic resonance imaging (fMRI): a form of MRI technology that monitors blood flow and oxygen consumption in the brain to identify areas of high activity
44.
gama-aminobutyric acid (GABA): an amino acid transmitter, widely distributed in the brain, that seems to produce only inhibitory postsynaptic potentials
45.
genes: DNA segments that serve as the key functional units in hereditary transmission
46.
genetic mapping: the process of determining the location and chemical sequence of specific genes on specific chromosomes
47.
genotype: a person's genetic makeup
48.
glia: cells found throughout the nervous system that provide various types of support for neurons (supply nourishment, remove waste, provide insulation)
49.
glutamate: an amino acid transmitter, widely distributed in the brain, that has only excitatory effects
50.
heterozygous condition: the two genes in a specific pair are different
51.
hindbrain: includes the cerebellum and two structures found in the lower part of the brainstem: the medulla and the pons
52.
hippocampus: a curved forebrain structure that is part of the limbic system; it plays a role in memory processes
53.
homozygous condition: the two genes in a specific pair are the same
54.
hormones: chemical substances released by the endocrine glands
55.
hypothalamus: a structure found near the base of the forebrain that is involved in the regulation of basic biological needs. Also serves as a vital link between the brain and the endocrine system; helps govern the release of hormones by the pituitary gland and regulates drives such as hunger and thirst
56.
identical (monozygotic) twins: twins that emerge from one zygote that splits for unknown reasons
57.
left hemisphere: specializes in verbal and analytical functions
58.
lesioning: destroying a piece of the brain naturally or experimentally
59.
limbic system (border): a loosely connected network of structures located roughly along the border between the cerebral cortex and deeper subcortical areas. It includes the hypothalamus, the hippocampus, the amygdala, the olfactory bulb and the cingulate gyrus. The limbic system is involved in the regulation of emotion, memory, and motivation
60.
long-term potentiation (LTP): durable increases in excitability at synapses along a specific neural pathway
61.
medulla: a brain structure attached to the spinal cord which controls unconscious but vital functions, including blood circulation, breathing, maintaining muscle tone and regulating reflexes such as sneezing, coughing, and salivating
62.
midbrain: the segment of the brainstem that lies between the hindbrain and the forebrain, involved in integrating sensory processes such as vision and hearing
63.
mirror neurons: neurons that are activated by performing an action or be seeing another person perform the same action
64.
monoamines: three transmitters: dopamine, norepinephrene, and serotonin
65.
morphine: a pain-killing drug derived from the opium plant which exerts its effects by binding to specialized receptors in the brain
66.
motor cortex: an area at the rear of the frontal lobes that controls voluntary movements
67.
MRI (magnetic resonance imaging): an imaging technique that uses magnetic fields, radio waves, and computerized enhancement to map out brain structure
68.
mutation: a random error in gene replication that leads to a change
69.
myelin sheath: A white, fatty covering wrapped around the axons of some neurons, which increases the speed at which nerve impulses travel along the axon.
70.
natural selection: heritable characteristics that provide a survival or reproductive advantage are more likely than alternative characteristics to be passed on to subsequent generations and thus come to be "selected" over time
71.
nerves: bundles of neuron fibers (axons) that are routed together in the peripheral nervous system; neural cables that connect the CNS with the muscles, glands, and sense organs
72.
nervous system: the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems
73.
neurogenesis: the formation of new neurons
74.
neurons: individual cells in the nervous system that receive, integrate, and transmit information in electrical and chemical forms. Neurons are the fundamental building blocks of the nervous system.
75.
neurotransmitters: chemical transmitters manufactured by neurons that transmit information from one neuron to another; they cross the synaptic gaps between neurons and bind to receptor sites on the receiving neuron, influencing whether that neuron will generate a neural impulse
76.
occipital lobe: located at the back of the head, includes the primary visual cortex, the area where most visual signals are sent and visual processing is begun
77.
parasympathetic nervous system: branch of the autonomic nervous system that calms the body, maintains bodily functions, and conserves energy;
78.
parietal lobe: located ahead of the occipital lobe, includes the primary somatosensory cortex, which receives signals from different parts of the body and is involved in integrating visual input and in monitoring the body's position in space
79.
Parkinsonism: a disease marked by tremors, muscular rigidity, and reduced control over voluntary movements
80.
perceptual asymmetrics: left-right imbalances between the cerebral hemispheres in the speed of visual or auditory processing
81.
peripheral nervous system (PNS): made up of all the nerves that lie outside the brain and the spinal cord; the part of the nervous system that extends outside the central nervous system, divided into the somatic and the autonomic nervous systems
82.
PET (positron emission tomography) scan: an imaging technique which examines brain function (activity), in which radioactively tagged chemicals are introduced into the brain, allowing blood flow or metabolic activity to be monitored with X-rays
83.
phenotype: the ways in which a person's genotype is manifested in observable characteristics
84.
pituitary gland: the "master gland" of the endocrine system, it releases a great variety of hormones that fan out around the body, stimulating actions in the other endocrine glands; regulates growth
85.
plasticity: the brain's ability to change, especially during childhood, or by reorganizing after damage or by building new pathways based on experience
86.
polygenic traits: characteristics that are influenced by more than one pair of genes
87.
pons ("the bridge"): a lower brainstem structure consisting of a bridge of fibers that connects the brainstem with the cerebellum
88.
postsynaptic potential (PSP): a voltage change at a receptor site on a postsynaptic cell membrane
89.
prefrontal cortex: a large portion of the frontal lobe that may contribute to higher order functions such as working memory, relational reasoning, and decision making
90.
recessive gene: the gene that is masked when paired genes are different (heterozygous)
91.
reflex: a simple, automatic response to a sensory stimulus, such as a knee-jerk response
92.
reticular formation: located at the central core of the brainstem, it regulates sleep and arousal and also contributes to the modulation of muscle reflexes, breathing, and pain perception
93.
reuptake: a process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane
94.
right hemisphere: focuses on nonverbal abilities such as art and music and visual recognition tasks
95.
sensory cortex: an area at the front of the parietal lobes that registers and processes body touch and movement sensations
96.
soma: the cell body, which contains the cell nucleus and much of the chemical machinery common to most cells
97.
somatic nervous system: a division of the PNS made up of nerves that connect to voluntary skeletal muscles and to sensory receptors. Also called the skeletal nervous system
98.
spinal cord: part of the CNS, connects the brain to the rest of the body through the peripheral nervous system, enclosed by the meninges and bathed in CSF
99.
split-brain patients: individuals whose cerebral hemispheres have been surgically disconnected
100.
split-brain surgery: a radical technique in which the corpus callosum is cut to reduce the severity of epileptic seizures
101.
sympathetic nervous system: branch of the autonomic nervous system that produces rapid physical arousal in response to perceived emergencies or threats; mobilizes the body's resources for emergencies
102.
synapse: a junction where information is transmitted from one neuron to another; located between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
103.
synaptic cleft: a microscopic gap between the terminal button of one neuron and the cell membrane of another neuron
104.
temporal lobe: located below the parietal lobe, includes the primary auditory cortex, which is devoted to auditory processing
105.
terminal buttons: small knobs that secrete neurotransmitters
106.
testosterone: a male sex hormone produced by the testes in men and in smaller amounts by women from the adrenal cortex and ovary
107.
thalamus: a structure in the forebrain through which all sensory information (except smell) must pass to get to the cerebral cortex
108.
threshold: the level of stimulation required to trigger a neural impulse
109.
transcranial magnetic stimulation (TMS): a technique that permits scientists to temporarily enhance or depress activity in a specific area of the brain
110.
twin studies: researchers assess hereditary influence by comparing the resemblance of identical twins and fraternal twins with respect to a trait
111.
Wernicke's area: an area in the temporal lobe of the left hemisphere that is involved with the comprehension of language
112.
zygote: a single cell formed by the union of a sperm and an egg
