Unit 3

Action Potential: When the chemical gates open up on a segment of the axon, an electrical charge is produced, then the next segment opens, and so on down the length of the axon.

Refractory Period: After the neuron fires, it cannot fire again for a certain period.

Threshold: The neuron will only fire when a certain threshold has been surpassed; this is the level of excitatory neurotransmitters that a neuron must absorb before firing.

All-or-None Response: The neuron either fires completely or doesn’t.

Synapse: The junction between the axon terminal and the dendrites of the neighboring neuron.

Neurotransmitters: Chemical messengers that cross the gap to trigger the next neuron.

Reuptake: Neurotransmitter's reabsorption by knob.

Endorphin: Neurotransmitters connected to pain control and pleasure.

Agonists: Binds to receptor site and stimulates response.

Antagonists: Binds to receptor site and stops response.

Sensory (Afferent) Neurons: Carry nerve impulses from receptors or sense organs towards the nervous system.

Motor (Efferent) Neurons: Carry impulses away from the CNS to effectors such as muscles or glands.

Interneuron Neurons: Form a connection between other neurons.

Reflexes: Simple, automatic, inborn response to sensory stimulus.

Hormones: Chemical messengers produced in the glandular tissue which affect other tissues.

Lesion: Any abnormal damage or change in the tissue of an organism, often caused by disease or trauma.

EEG: An amplified recording of waves of electrical activity that sweep across the brain’s surface.

Computed Tomography Scan (CT): Uses radiation. Shows structure, not function.

Magnetic Resonance Imaging (MRI): Uses magnetic fields and radio waves to generate a detailed image of soft tissues.

Functional MRI (fMRI): Does everything an MRI can, but also reveals blood flow and activity.

Positron Emission Tomography (PET): Patient ingests radioactive glucose and the areas of high activity where the glucose is being metabolized light up.

Brainstem: Responsible for automatic survival functions.

Reticular Formation: Network of nerves, important for arousal.

Limbic System: Emotional center of the brain associated with fear, aggression, hunger, and sex drive.

Cerebral Cortex: The intricate fabric of interconnected neural cells that covers the cerebral hemispheres.

Glial Cells: Non-neuronal cells that provide support and protection for neurons located in the central nervous system.

Motor Cortex: Controls voluntary muscle movements.

Somatosensory Cortex: Body touch and movement sensations.

Association Areas: Parts of the cerebral cortex responsible for higher-level functions like thinking, learning, memory, and speaking.

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

Neurogenesis: The process of producing new neurons.

Corpus Callosum: A band of nerve fibers that connect the brain's left and right hemispheres together.

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.

Cognitive Neuroscience: A branch of psychology that explores how the brain influences cognitive processes such as perception, memory, and language.

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

Michael Gazzaniga: Studied the neural basis of mind with primary responsibility for initiating human split-brain research.

Roger Sperry: Discovered that human beings are of two minds. He found that the human brain has specialized functions on the right and left, and that the two sides can operate practically independently.

Behavior Genetics: The study of relative influences of heredity and genetics based on behavior.

Chromosomes: Threadlike structures made of DNA which contain our genes.

DNA: Complex molecule containing the genetic information that makes up the chromosomes.

Genes: Units of heredity that make up chromosomes, segments of DNA capable of synthesizing protein.

Genome: The complete set of instructions for making an organism, containing all the genes in that organism.

Identical Twins: Twins who develop from a single fertilized egg.

Fraternal Twins: Twins who develop in separate fertilized eggs.

Molecular Genetics: The study of molecular structure and function of genes.

Heritability: The extent to which variation among individuals can be attributed to differing genes.

Epigenetics: The study of the environmental influences on genetic expression that occur without a DNA change. (EX: Radiation)

Natural Selection: An evolutionary process through which adaptive traits are passed on from generation to generation because these traits help the organism survive and reproduce.

Mutation: Random error in gene replication that leads to a change.