Biological Bases of Behavior
Mutation: a random error in gene replication that leads to a change.
Epigenetics: "above" or "in addition to" (epi) genetics; the study of the molecular mechanisms by which environments can influence genetic expression (without a DNA change).
Central Nervous System (CNS): the brain and spinal cord.
Peripheral Nervous System (PNS): the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
Nerves: bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sensory 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.
Myelin [MY-uh-lin] sheath: a fatty tissue layer segmentally encasing the axons of some neurons; it enables vastly greater transmission speed as neural impulses hop from one node to the next.
Glial Cells (glia): cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning, thinking, and memory.
Threshold: the level of stimulation required to trigger a neural impulse.
Refractory Period: in neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state.
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.
Reuptake: a neurotransmitter's reabsorption by the sending neuron.
Endorphins: "morphine within”; natural, opioid-like neurotransmitters linked to pain control and to pleasure.
Agonist: a molecule that increases a neurotransmitter's action.
Antagonist: a molecule that inhibits or blocks a neurotransmitter's action.
Autonomic Nervous System (ANS): 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.
Somatic Nervous System: the division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system.
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.
Long-Term Potentiation (LTP): an increase in a nerve cell's firing potential after brief, rapid stimulation; a neural basis for learning and memory.
Neuroplasticity: the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.
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.
Hormones: Implied through the mentioning of "Endocrine"
Brainstem: the central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions.
Medulla: the hindbrain structure that is the brainstem's base; controls heartbeat and breathing.
Thalamus: the forebrain'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.