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Fall_2006_Biopsych_one_genetics_neurotransmitters -...

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Unformatted text preview: Biological Psychology I: Genetics, the Nervous System and Neurotransmitter Processes Overview of Today's Lecture *Introduction to the role of genetics *Structure of the Nervous System *Review of elementary Neuronal Structure and Physiology *Neurotransmitters and Their Neuronal and Psychological Functions *A Few Practical Illustrations/Applications Some Orienting Concepts on Genetics in Psychology: *What is "Genetics"? *A) Heredity of specific characteristics: *e.g. Mendel's peas: Fig. 3.2 *B) Processes involved in turning genes on and off: *C) polygenic effects: *Chromosomes: *What Genes are: *What Genes do: *Gene Expression: *"Epigenetic" modifications of genes and the impact for human health (cancer, stress-reactivity, etc): Genes Affect Behavior *Behavioral Genetics Methods: *Twin Studies Compare MZ and DZ Twins: *Adoption Studies: *Heritability: Gene Expression Can Be Modified *Manipulating Genes: *Pick your Mouse (or person?) *Alcohol preferences video: *Manipulating Environments: *"Mother Nurture" article: *"epigenetics" again, stress-reactivity: How Are Neural Messages Integrated into Communication Systems? *Three systems are coordinated: *1)The Central Nervous System (CNS) *2) The Peripheral Nervous System (PNS) *3) The Endocrine System Structure of the Nervous System: The Central Nervous System (CNS) Consists of the Brain and Spinal Cord The Peripheral Nervous System (PNS) connects the CNS to the rest of the body through subdivisions: *1) The Somatic Nervous System, which acts on skeletal muscles (the muscles attached to bone) *2) The Autonomic Nervous System, which acts on visceral muscles (e.g., heart, arteries, gastrointestinal tract) and glands (e.g., salivary, sweat) In the Somatic Nervous System: 1) Sensory Neurons (Afferent Neurons) transmit somatosensory information from peripheral sensory organs to CNS; and 2) Motor Neurons (Efferent Neurons) bring motor informational commands from CNS to the muscles: Fig. 3.8 In the Autonomic Nervous System: 1) The Sympathetic Nervous System is activating ("Fight or Flight") 2) The Parasympathetic Nervous System is deactivating ("Rest and Digest") The Endocrine System Communicates Through Hormones Actions of the Nervous System and Endocrine System Are Coordinated *The hypothalamus is a critical integrating structure, as will be explored in the next lecture on brain structure and function. "Stress" and The HPA-Axis *HPA stands for: *Example of Stress-Response: *The consequences of dysregulation in the human stress response: Neurons, Nerves, and "Tracts": *Neuron: *Nerve: *Tract: Peripheral Nervous System consists of entire set of "nerves" (cranial and spinal) Neurons are specialized for communication: What happens at the: *Dendrites? *Cell Body? *Axons? Some neurons have "myelin sheaths" and "nodes of ranvier": What are those? J A "node of ranvier" is the space between two myelin sheaths on an axon where depolarization and action potentials occur A Myelin sheath: * Is made from glial cells *Provides insulation for axons *Speeds up neural transmission by causing action potentials to "jump" across the "nodes of ranvier" (called "saltatory conduction") *Saltatory conduction produces faster neural speed and thereby increases how quickly effects at the synapse can occur Myelin sheaths are made from glial cells Neurons are supported by glial cells, but are different Glial Cells *Called Glia *Outnumber Neurons 10:1 in CNS *Form Myelin Sheaths, Blood/Brain Barrier, Help Supply Nutrients to Neurons, etc. *Different Varieties, Different Functions Illustration: 3 Types of glial cells and their structures and functions: *Oligodendrocytes: *Schwann Cells: *Astrocytes: The other half image: Different types of neurons serve different purposes 3 Classes of Neurons: *Motor Neurons *Sensory Neurons *Interneurons *1) Motor Neurons ( also called efferent nerves): CNS --> muscles/glands (enable us to move, e.g.) *2) Sensory Neurons (also called afferent nerves) : Sensory Organs --> CNS (enable us to perceive sensory inputs, like touch) *3) Interneurons: Within CNS Transmission *perform integration and organization functions *vastly outnumber Motor and Sensory Neurons (several millions of each compared to 100 billion interneurons) Animation of Neurotransmitters in Brain Review of Handout (Roberts' "Elementary Lesson in Neurophysiology") Monoamine Oxidase Inhibitors and SSRI's both are agonists of Serotonin, but have different mechanisms of action: See figure 3.15 for review Neurotransmitters and Psychological Function Neurotransmitters: Acetylcholine (Ach) *Links Motor Neurons and Muscles (synapse at muscle) Slide 35 *Curare is Ach antagonist, leading to temporary muscle paralysis *Ach is involved in Learning and Memory in CNS *Alzheimer's Patients Have Low Levels of Ach Video Example: *This Experiment by Joseph Martinez' explores the causal relationships between CNS Acetylcholine Processes and Learning and Memory Processes ("consolidation" of learning) *Be sure to take detailed notes to be able to reconstruct the specific details of the experiment: Analysis/Reconstrtuction of Martinez' Experiment From Video *What is the operational IV? *A: Scopolomine (action: Ach Antagonist) vs. Saline (Question: Why the saline injection?) *Implied Physostygmine (Ach Agonist) Could be Another Level of IV *How might subjects and experimenters have been blind? Analysis of Martinez' (continued) *What is the operational DV? *(A: "Time" to find food) *What is the theoretical DV? *(A: "Memory" as a function of biochemical variables) *Results and Conclusions: *Scopolomine Caused ...................... *Physostygmine Caused ................... Neurotransmitters: Dopamine (DA) *Involved in muscular activity *In Parkinson's Disease, tracts of DA neurons degenerate in Basal Ganglia, leading to abnormally low levels in brain *Excesses involved in Schizophrenia? *Antipsychotic Medications are DA antagonists, interfering with DA at post- synaptic receptors *DA Tracts "project" widely through areas of brain (limbic system and cortical structures) dealing with emotion/motivation and thinking/planning/judgment/language Neurotransmitters: Norephinephrine (NE) *Increases Arousal *Increased levels may be involved in Mania *Decreased levels may be involved in Depression *Tricyclic antidepressant medications inhibit reuptake, thus functioning as NE agonists Neurotransmitters: Serotonin (5-HT) *Involved in sleep-wakefulness rhythms *Massively depleted by Ecstacy (terminal buttons often destroyed)--see "Buzzed" article *Discussion of Ecstasy Chapter: *Decreased Levels may lead to depression *Reuptake Inhibited by Prozac (Fluoxetine) *Prozac is in a class of drugs called SSRI's (Selective Serotonergic Reuptake Inhibitors), all of which are 5-HT agonists Neurotransmitters: Gamma Aminobutyric Acid (GABA) *Lowers arousal *Reduces anxiety *GABA is the main inhibitory NT in nervous system Conclusion: *All Psychological Functions (behavioral-motor activation, attention, anxiety, mood, thought, speech, consciousness, intentionality and impulsivity, etc.) are supported and regulated by complex interactions between the CNS and PSN, with diverse types of CNS neurotransmitters playing a central and critical role in our psychological existence, identity, and experience of the world *The machinery of mind underlies psychological realities ...
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