PSYC 101 1st Edition Lecture 4 Outline of Last Lecture: Research Methods in Psychology Continued I. CorrelationA. ExamplesII. Why Do We Use Correlation?a. When experimenting is unethicalb. When experimentation is impossible or too difficultc. When looking at traits that cannot be controlled III. Does Correlation Mean Causation? No!a. Correlation Rangeb. ExamplesIV. ExperimentationV. Basic Termsa. Experimental Conditionsb. Control Conditionc. Random Assignmentd. Independent Variablee. Dependent Variablef. ExampleOutline of Current Lecture II. NeuronsIII. Basic Terminology: Neural Partsa. Neuronb. Dendritec. Cell Bodyd. Axoni. Axon Terminal Buttonsii. White Matteriii. Gray Mattere. Myelin Sheathi. Protectionii. Insulationiii. Processing Speedf. Synapse (Synaptic Gap)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.g. Receptor h.Action Potentiali.Thresholdj.Depolarizationi.Resting Potential: -75ii.Action Potential: +10k.Refractory Periodl.All-or-Nonem.Hyperpolarization Current Lecture: Neural Communications – The BrainI. Neuronsa. Nucleus: includes DNA, mitochondria, etc. b. Job: pass information c. Communicate through electrochemical transmission (neurotransmitters)d. Neurons never actually touch! II. Basic Terminology – Neural Partsa. Neuron: basic building blocks of the nervous systemb. Dendrite: part of the neuron that receives messages from other cells (neurons, chemicals, hormones, etc.) passes message to the cell body c. Cell Body (Soma): control center of neurons, contains nucleus d. Axon: sends message to other neurons, glands, muscles, etc. – some are really long, some really short.i. Axon Terminal Buttons – branches at the end of the axon that contain vesicles enclosing neurotransmittersii. A nerve is a bundle of axonsiii. White matter: Contains a lot of axons – communication throughout the brainiv. Gray Matter (Cortex): 1/4th inch thick, contains significantly less axons – think, plan, sense, see, memoryv. Ex: nerves in your foot have a long axon that extends up your leg to your spinal corde. Myelin Sheath: Fatty tissue that covers the axon in some neuronsi. Protectionii. Insulationiii. Speeds up the neural impulse iv. Ex: Multiple Sclerosis (MS) is a disorder in which the myelin disintegrates, eventually slowing down the nervous system f. Synapse (Synaptic gap): junction between axon (axon terminal buttons) of one neuron and the dendrite of another neuron – Neurons never touch! If one neuron were damaged, it would affect the entire nervous system, if neurons did touchg. Receptor: protein that binds neurotransmitters, hormones, or drugs: interaction with chemicalsi. Exists at the end of the axon (axon terminal) ii. Axon terminal holds vesicles that contain neurotransmittersiii. If the electrical signal reaches its action potential, neurons cross synaptic gap and bind to receptor sites h. Action Potential: brief electrical charge that travels down an axon. Caused by positively charged ions (mostly sodium neurons Na+) moving in and out of channels on axons membrane. i. Action Potential must reach threshold in order for the neuron to send themessagei. Threshold: the level of simulation required to trigger an action potential. Threshold is reached through depolarization.j. Depolarization: when the inside of an axon becomes more positive through an inward flow of positive ions; most of the time, directly binding neurotransmitters to receptors, chain reactioni. Resting Potential: typically -75; meaning the axon contains mostly negative ionsii. Action Potential to reach Threshold & Depolarization: +10; so positive ions must flow into axon altering -75 to +10 in order for the neurotransmitter to pass through the synaptic gap into the receptor (dendrite) of another neuron iii. After the signal reaches a threshold of +10, and depolarization occurs, there must be a refractory periodk. Refractory Period: the period in which a new action potential cannot occur; haveto reset i. Positive ions outii. Negative ions in iii. Back to -75iv. Ex: Cannot flush the toilet immediately after just flushing l. All-or-None: Action Potential cannot be partial; they either happen or they don’t.i. Not the size of the action potential: it’s the amountii. Ex: Seeing a guy with a chainsaw vs. seeing your mom1. Action potential: +10 in both scenarios2. Reaction to scenarios is extremely different! 3. Number of action potentials encoded – number of signals sent decides how quickly the message is receivediii. Ex: 2+2=41. Action potential: +102. Over time, the signal is sent more, so the amount of action potential increases3. Therefore, it is a simple and quickly answerable math equation m. Hyperpolarization: return of the inside of the axon of more negative ions; opposite of depolarization; some neurons hyperpolarize to move neurons fartheraway from action potential, therefore the signal will not be sent i. Add –ions or take out +ionsii. Ex: Anxietyiii. Drug example: Xanax – causes hyperpolarization, shutting neurons down: feel relaxed,