PSY 201 1st Edition Lecture 4Outline of Last Lecture II. Scientific Methoda. Goals of scienceb. Experiment stepsIII. Types of studiesa. Research designb. Measurement methodsc. SettingsIV. Statistical Methodsa. Descriptive/inferential statisticsV. Problems of interpreting resultsOutline of Current Lecture II. Cell types: neurons, glia and blood vesselsIII. Nerve Cell Communicationa. Nerve impulse (action potential)b. Synaptic transmissionc. Neural integrationd. Neurotransmitters and the effects of drugsIV. Learning in Neural NetworksV. Cerebral Cortexa. Functional Specializationb. Topographic organizationc. Contralateral connectiond. Asymmetry of higher functionsCurrent LectureII. Cell typesa. Glia: ‘helper cells’, form myelin sheathsb. Blood vesselsi. Carry blood and glucose to and around the nervous systemii. 40% of blood pumped by the heart goes to the headc. Neuronsi. Receive, integrate and transmit informationii. Operate through electrical impulses and communicate through chemicals (neurotransmitters)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.iii. Structure (Note: a picture can be found on pg.77 of the text)1. Dendrite: receives information2. Cell body: integrates information3. Axon: transmits the information (covered by myelin sheath to expedite the transmission)4. Synapse: at the end of the axon, where neurons make contact5. Terminal buttons: nodes that release chemicals (neurotransmitters) into the synaptic clefa. Contain synaptic vesiclesiv. Signals are generated by action potential 1. Communication based on electrochemical signalsv. Reflex circuit1. Reflex: built in response patterns executed automatically2. Pain withdrawal reflexa. Comprised of the Central Nervous System (CNS) and the Peripheral Nervous System (PNS)b. Signals transmit through sensory neurons, interneurons and motor neuronsIII. Nerve Cell Communicationa. Membrane potential: the charge across the membranei. Protein gates and pumps in the membrane control ion movement and therefore the charge of the membraneii. Resting potential: negative charge (-70 mv)iii. Sodium/Potassium pump: places more sodium outside, and more potassium inside1. The membrane tries to equalize charge and concentrationiv. Action potential1. Rapid reversal of membrane potentiala. (-55 mv) threshold potentialb. reversal: inside of the neuron becomes more positive, and then returns to normali. Sodium channels open, sodium rushes in, and the potential from the positive ions makes the cell positive (stop when it becomes +50mv)ii. Potassium enters, and the potassium gates rush outof the cell until the membrane charge returns to normalc. Spreads along the axon to the terminal buttonsi. Sends chemicals into the synaptic clef1. Activation of receptors on the next neuron2. Produces an excitatory or inhibitory effecta. Excitatory: makes the neuron more positiveb. Inhibitory: makes neuron more negativeb. Neural integrationi. Receiving neuron integrates signals from dendrites continuouslyii. Temporal and spatial summation of PSP’s at axon1. Many EPSP’s occurring over time; cell fires many action potentials2. Firing rate of action potentials is the message a neuron communicates to the next neuronsa. Increases as the stimulus intensity increasesc. Neurotransmitters and the effects of drugsi. Events ending transmitter influence:1. Reuptake: to presynaptic terminal button2. Enzymes: deactivate neurochemical3. Autoreceptors: signal the axon to stop releasing the neurotransmittera. Agonists: increase the release of neurotransmitters, can block the reuptake of neurotransmittersi. Bind to postsynaptic receptorb. Antagonists: block the release of neurotransmitters, and destroy neurotransmitters in the synapsei. Block receptors on postsynaptic cellii. Effects on behavior1. Addictive drugs (cocaine, meth, alcohol, nicotine, heroine)a. Cause increase in activity in ‘reward circuits’i. Basal ganglia and limbic system1. Normally active during pleasant experiencesb. Drugs cause a huge increase in release/effects of dopaminei. AKA dopamine agonists (block dopamine reuptake, therefore not allowing dopamine to be returned to the presynaptic neuron)ii. Associated with increased arousal and euphoriaiii. Dopamine in these regions serves as a source of motivation and motor control, so behavior is guided towards rewarding experiences1. Leads to cravings and behaviors to attain the experience again (addiction)2. Problema. Long term use can permanently change brain chemistryi. Decrease in dopamine production over time, decrease activation in the circuits and impaired abilities1. Memory, judgment, motor coordination2. Using drugs just to feel normalIV. Learning in Neural Networksa. Correlated firing of a pre/post synaptic cell strengthens the synapse between them so the presynaptic cell becomes more effective (produces larger EPSP’s) in firing the postsynaptic neuroni. “Cells that fire together wire together”ii. Basis for long term memories and normal development of sensory systems1. Ex: association of a smell with a certain memoryV. Cerebral cortexa. Cerebral cortex: perception, language, memory, planning, intellectual/artistic function, social responsibility, emotions, conscious thought, action, etc.i. 4 lobes (6 cell layers), with gray matter (cell bodies, dendrites, synapses, first layer) and white matter (myelinated axons, second layer under gray matter)1. Frontal lobe2. Occipital lobe3. Temporal lobe4. Parietal lobeb. Functional localization: different parts of cortex serve different functionsi. Early theories: phrenology1. Bumps on the skull surface correspond to personality traitsa. Not considered valid in modern day2. Attempt to localize cognitive functionii. Modern methods1. Discovery of a massive vascular system to support the brain’s high metabolic needs2. FMRI: measures levels of blood flow to give functional images of brainsa. Study exclusively human behaviorsc. Cortical areasi. Cortex consists of multiple topographically organized areas1. Primary sensory areas: receive direct input from sensory surface2. Primary motor area: sends axons down to motor neurons in brain stem/spinal cord, electrical stimulation produces twitchesii. Association areas: areas beyond primary areas, receive inputs from other sensory areas (generally only represents info from one mode/sense system)1. Sensory areas detect