Chapter 3 Biological

389 views

Published on

Published in: Technology, Education
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
389
On SlideShare
0
From Embeds
0
Number of Embeds
9
Actions
Shares
0
Downloads
13
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Chapter 3 Biological

  1. 1. 3 Chapter 3 Biological Aspects of Psychology
  2. 2. 3 Biology and BehaviorBiology and Behavior • Cells of the Nervous System • Neural Transmission • The Nervous System • The Peripheral Nervous System: Keeping in Touch with the World • The Central Nervous System: Making Sense of the World • Techniques for Studying Human Brain Function and Structure • The Chemistry of Behavior: Neurotransmitters • The Endocrine System: Coordinating the Internal World • Linked Exercises
  3. 3. 3 Biological PsychologyBiological Psychology • All behavior and mental processes are based on biology. – But, are also influenced by the environment • Two primary systems direct the activities of the body. – The nervous system – The endocrine system
  4. 4. 3 Three Functions of the Nervous System Back to TOC
  5. 5. 3 Cells of the Nervous SystemCells of the Nervous System What are neurons,What are neurons, and what do they do?and what do they do?
  6. 6. 3 Cells of the Nervous SystemCells of the Nervous System • NeuronsNeurons – Have the ability to send and receive signalsHave the ability to send and receive signals – Organized in neural networks • Glial cellsGlial cells – Help neurons communicateHelp neurons communicate – Malfunctions may lead to problemsMalfunctions may lead to problems
  7. 7. 3 A Typical Neuron • Cell body – Similar to other cells • Axon – Sends signals to other neurons • Dendrites – Receive signals from other neurons
  8. 8. 3 Axons • Function: – Carry signals away from the cell body. – Myelin sheath helps speed the action potential • Type of Signal Carried: – The action potential • An all-or-nothing electrochemical signal • Travels down the axon, releasing neurotransmitters from vesicles
  9. 9. 3 Dendrites • Function: – Detect and carry signals to the cell body. • Type of Signal Carried: – Excitatory postsynaptic potential: electrochemical signal which encourages a neuron to fire. or – Inhibitory postsynaptic potential: electrochemical signal which discourages a neuron from firing.
  10. 10. 3 | 1 The Cell Body of a Neuron • Outer membrane – passes some substances, blocks others • Nucleus – Genetic information • Mitochondria – convert glucose and oxygen into energy Back to TOC
  11. 11. 3 | 1 Neural Transmission How do neurons communicate?
  12. 12. 3 | Video: The Beginning of an Action Potential
  13. 13. 3 | 1 Synapses • Areas for the transfer of signals between neurons • Neurotransmitters cross to receptors on other cells
  14. 14. 3 | 1 A Synapse This photograph shows part of a synaptic gap between two neurons, magnified 50,000 times. The ending of the presynaptic cell’s axon is shaded green, the green ovals are mitochondria, and the red spots are the vesicles. The synapse itself is the narrow gap between the first cell’s green-shaded axon and the blue-shaded dendrite of the cell below.
  15. 15. 3 | 1 Neurotransmitters • Chemicals released by one cell that bind to the receptors on another cell • Tell the next cell to fire or not to fire its own action potential
  16. 16. 3 | 1 Receptors • Proteins on the cell membrane that receive chemical signals • Recognize specific neurotransmitters – Allows them to begin postsynaptic potentials in the dendrite
  17. 17. 3 | Integration of Neural Signals • Signals arrive from many neighboring cells – Excitatory signals encourage firing – Inhibitory signals discourage firing • Firing depends on which messages predominate – The all-or-nothing law Back to TOC
  18. 18. 3 | 1 The Nervous System The nervous system has two major divisions – Central Nervous System (CNS) – Peripheral Nervous System (PNS) Back to TOC
  19. 19. 3 | The Peripheral NervousThe Peripheral Nervous System: Keeping in TouchSystem: Keeping in Touch with the Worldwith the World How do sights and soundsHow do sights and sounds reach my brain?reach my brain?
  20. 20. 3 | Autonomic Nervous SystemAutonomic Nervous System • Controls activities normally outside ofControls activities normally outside of conscious control.conscious control. • Two SubsystemsTwo Subsystems – Sympathetic nervous systemSympathetic nervous system • ““Spends” energySpends” energy – Parasympathetic nervous systemParasympathetic nervous system • ““Preserves” energyPreserves” energy
  21. 21. 3 | 2 Somatic Nervous System • Sensory neurons (afferent neurons) – Send sensory information to CNS • Motor neurons (efferent neurons) – Send messages from CNS to muscles Back to TOC
  22. 22. 3 | The Central Nervous System:The Central Nervous System: Making Sense of the WorldMaking Sense of the World How is my brainHow is my brain “wired”?“wired”?
  23. 23. 3 | 2 The Spinal Cord • Relays signals from the senses to the brain. • Relays signals from the brain to the muscles. • Directs reflexes.
  24. 24. 3 | A Reflex Pathway Tapping your knee at just the right spot stimulates sensory neurons to fire, triggering spinal neurons to fire. This stimulates the firing of motor neurons with axons ending in your thigh muscles, causing you to kick. Information about all this also goes to your cerebral cortex, but the reflex happens without waiting for guidance from the brain. Back to TOC
  25. 25. 3 | 2 Techniques for Studying Human Brain Function and Structure Taking a Closer Look
  26. 26. 3 | EEGEEG (Electroencephalography)(Electroencephalography) • Technique:Technique: – Multiple electrodes pasted to outside of headMultiple electrodes pasted to outside of head – Senses electrical fields resulting from neural activitySenses electrical fields resulting from neural activity • What it shows:What it shows: – General electrical activity of the brainGeneral electrical activity of the brain – Represented as a line on a graph or screenRepresented as a line on a graph or screen
  27. 27. 3 | EEGEEG (cont(cont’d)’d) • Advantages:Advantages: – Detects very rapid changes in electrical activityDetects very rapid changes in electrical activity – Allows analysis of stages of cognitive activityAllows analysis of stages of cognitive activity – May be combined with magnetoencephalographyMay be combined with magnetoencephalography (MEG) to localize activity(MEG) to localize activity • Disadvantages:Disadvantages: – Poor spatial resolution of the source of activityPoor spatial resolution of the source of activity
  28. 28. 3 | 2 PET (Positron Emission Tomography) and SPECT (Single-Photon Emission Computerized Tomography) • Technique – Positrons and photons emitted by radioactive substances • What they show – Indicate specific changes in neuronal activity
  29. 29. 3 | 2 PET and SPECT (cont’d) • Advantages – Allow functional and biochemical studies – Provide visual image corresponding to anatomy – Better spatial resolution better than EEG • Disadvantages – Require exposure to low levels of radioactivity – Inferior spatial resolution to MRI – Cannot follow changes faster than 30 seconds
  30. 30. 3 | MRIMRI (Magnetic Resonance Imaging)(Magnetic Resonance Imaging) • Technique:Technique: – Expose the brain to a magnetic field and measureExpose the brain to a magnetic field and measure radio frequency wavesradio frequency waves • What it shows:What it shows: – High resolution image of brain anatomyHigh resolution image of brain anatomy
  31. 31. 3 | MRI (cont)MRI (cont) • AdvantagesAdvantages – No radioactivityNo radioactivity – High resolution of anatomical details (<1 mm)High resolution of anatomical details (<1 mm) – High temporal resolution (<1/10 of a second)High temporal resolution (<1/10 of a second) • Disadvantages – Does not indicate functions as they happen
  32. 32. 3 | 3 Combining a PET Scan and Magnetic Resonance Imaging Combining these techniques provides three-dimensional views of living brains
  33. 33. 3 | 3 Functional MRI (fMRI) • Combines the advantages of PET and MRI • Detects changes in blood flow and oxygen that reflect ongoing changes in neural activity • Resulting computer analysis shows areas of the brain that appear activated during a task • Exciting developments: – Discovery of the mirror neuron mechanism – Investigating the effects of acupuncture
  34. 34. 3 | 3 Video: Mirror Neurons
  35. 35. 3 | 3 Critical Thinking about fMRI • Indicates location of brain activity, but not cause • Does not tell us how brain works • Does not measure brain cell activity directly, but measures change in blood flow and oxygen • Subject to experimenter bias in interpretation
  36. 36. 3 | TMSTMS (Transcranial Magnetic Stimulation)(Transcranial Magnetic Stimulation) • Technique:Technique: – Temporarily disrupt activity of a small region of theTemporarily disrupt activity of a small region of the brain with an intense magnetic fieldbrain with an intense magnetic field • What it shows:What it shows: – Loss of normal function of a particular brain regionLoss of normal function of a particular brain region
  37. 37. 3 | TMSTMS (cont(cont’d.)’d.) • AdvantagesAdvantages – Shows brain regions needed for given tasksShows brain regions needed for given tasks – May treat depression and migraine headaches • DisadvantagesDisadvantages – Long-term safety not well establishedLong-term safety not well established
  38. 38. 3 | Video: Brain Organization,Video: Brain Organization, Structure and FunctionStructure and Function
  39. 39. 3 | DTI (Diffusion Tensor Imaging) • Variant of fMRI • Traces activity of axon pathways
  40. 40. 3 | Major Structures of the Hindbrain • Medulla oblongata – Controls vital functions – blood pressure – heart rate – breathing • Reticular formation – Arousal – Attention • Cerebellum – Coordinates movement – Timing • Locus coeruleus – Directs attention
  41. 41. 3 | Major Structures of the Forebrain • Cerebral cortex – Processes complex information • Suprachiasmatic nuclei – Maintain circadian rhythms • Striatum & substantia nigra – Coordinate smooth movement • Corpus callosum – Connects left and right hemispheres • Thalamus – Relays and processes sensory signals
  42. 42. 3 | Major Structures of the Forebrain The Limbic System • Amygdala – Involved in emotion • Hippocampus – Formation of memories – Affected by Alzheimer’s disease • Hypothalamus – Regulates drives • Septum – Pleasure – Anger suppression
  43. 43. 3 | 4 Anatomical Areas of the Cerebral Cortex Each hemisphere is into four lobes: • Frontal • Parietal • Occipital • Temporal Divided by • Gyri (ridges) • Sulci (valleys)
  44. 44. 3 | 4 Functional Areas of the Cerebral Cortex • Motor cortex • Controls movement • Sensory cortex • Receives sensory information • Association cortex • Integrates information • Wernicke’s area • Language interpretation • Broca’s area • Language organization • Speech production
  45. 45. 3 | 4 Motor and Somatosensory Cortices • Motor cortex – Moves parts of the body – Areas controlling movement of neighboring parts of the body occupy neighboring parts of the motor cortex • Somatosensory cortex – Receives sensory input from body parts – Areas receiving input from neighboring body parts are near one another in the sensory cortex
  46. 46. 3 | Lateral Dominance in Normal Brains • Hemispheric Differences – Left: • logical abilities • language abilities – Right: • spatial abilities • artistic abilities • musical abilities • facial recognition – Individual variability in the precise nature and degree of lateralization – Differences should not be exaggerated • Corpus callosum allowsCorpus callosum allows the two hemispheres tothe two hemispheres to work closely togetherwork closely together
  47. 47. 3 | Split-Brain StudiesSplit-Brain Studies • Apparatus for studying split-brain patients – Presents image to selected visual fieldPresents image to selected visual field • In left visual field:In left visual field: – Can name the objectCan name the object • In right visual field:In right visual field: – Cannot describeCannot describe object in wordsobject in words – Can pick the objectCan pick the object out of a groupout of a group
  48. 48. 3 | Neural PlasticityNeural Plasticity • CNS can:CNS can: – Strengthen neural connections at synapsesStrengthen neural connections at synapses – Establish new neural connectionsEstablish new neural connections • Basis for forming new memories and learningBasis for forming new memories and learning • Limits to plasticity in repairing brain damageLimits to plasticity in repairing brain damage
  49. 49. 3 | 4 Helping the CNS to Heal • Transplant fetal tissue into the adult’s brain • Coax brain to make its own new neurons – Problem: Synaptic connections must be reestablished. • Block the action of the CNS protein, “Nogo” • “Growth factor” proteins • Special mental and physical exercise programs • Neural stem cells in adults’ brains – Special glial cells can form new tissue, including neurons Back to TOC
  50. 50. 3 | 5 Linkages: Human Development and the Changing Brain • Correlation between changes in neural activity and the behavior of newborns and infants – Newborns: • High activity in thalamus • Purposeful sweeping movements of arms and legs – 2-3 months old: • Increased activity in much of the cortex • Loss of reflexes such as grasping – 8-9 months old: • Increased activity in frontal cortex • Increased cognitive activity
  51. 51. 3 | Linkages: Human Development and the Changing Brain Childhood and adolescence • 6-7 years old: – More dendrites than adult brains – Use twice the metabolic fuel of adult brains • Adolescence: – Pruning of synapses – Loss of gray matter • Developmental changes reflect plasticity, not appearance of new cells
  52. 52. 3 | Linkages: Human Development and the Changing Brain (cont’d) • Genes determine basic pattern of growth and major lines of connections. • Enriched environments encourage neural development Back to Linked Exercises Back to TOC
  53. 53. 3 | The Chemistry of Behavior:The Chemistry of Behavior: NeurotransmittersNeurotransmitters How do biochemicalsHow do biochemicals affect my mood?affect my mood?
  54. 54. 3 | The Chemistry of Behavior • Neurotransmitter systems: groups of neurons that uses the same neurotransmitter to communicate – Play dominant roles in particular functions. • Neuromodulators act on receptors at synapses. – Modify or “modulate” a cell’s response to other neurotransmitters.
  55. 55. 3 | 5 Small Molecule Neurotransmitters Neurotransmitter Normal Function Disorder Associated with Malfunction Acetylcholine Memory, movement Alzheimer’s disease Norepinephrine Mood, sleep, learning Depression Serotonin Mood, appetite, impulsivity Depression Dopamine Movement, reward Parkinson’s disease, schizophrenia GABA Sleep, movement Anxiety, Huntington’s disease, epilepsy Glutamate Memory Damage after cardiovascular accident
  56. 56. 3 | 5 Other Classes of Neurotransmitters Neurotransmitter Normal Function Disorder Associated with Malfunction Peptides Endorphins Pain control No established disorder Gases Nitric oxide Memory No established disorder Back to TOC
  57. 57. 3 | The Endocrine System:The Endocrine System: CoordinatingCoordinating the Internal Worldthe Internal World How can my hormonesHow can my hormones help me in a crisis?help me in a crisis?
  58. 58. 3 | The Endocrine System • Regulates functions – Stress responses – Physical growth • Communicates by secreting hormones • Controlled by hypothalamus via pituitary gland • Negative feedback system Back to TOC
  59. 59. 3 | Linked Exercises • Linkages: Human Development and the Changing Brain • Thinking Critically:Thinking Critically: What Can fMRI Tell Us about Behavior and Mental Processes?What Can fMRI Tell Us about Behavior and Mental Processes? • Focus on Research Methods: Manipulating Genes in Animal Models of Human Disease
  60. 60. 3 | Thinking Critically:Thinking Critically: What Can fMRI Tell Us aboutWhat Can fMRI Tell Us about Behavior and Mental Processes?Behavior and Mental Processes? • What am I being asked to believe or accept?What am I being asked to believe or accept? – fMRI is a 21fMRI is a 21stst century version of phrenologycentury version of phrenology • Is evidence available to support the claim?Is evidence available to support the claim? – Neuron firing rates may cancel each other out onNeuron firing rates may cancel each other out on scansscans – Problems with interpreting fMRI resultsProblems with interpreting fMRI results – Difference rules are decided by experimentersDifference rules are decided by experimenters – Differences do not necessarily reflect actual thinkingDifferences do not necessarily reflect actual thinking differencesdifferences
  61. 61. 3 | Thinking Critically:Thinking Critically: What Can fMRI Tell Us aboutWhat Can fMRI Tell Us about Behavior and Mental Processes?Behavior and Mental Processes? (cont(cont’d.)’d.) • Can that evidence be interpreted another way?Can that evidence be interpreted another way? – Image changes mirror thinking and feeling changesImage changes mirror thinking and feeling changes – fMRI led to discovery of mirror neuron mechanismsfMRI led to discovery of mirror neuron mechanisms • What evidence would help evaluate theWhat evidence would help evaluate the alternatives?alternatives? – Actual relationship between scanned activity andActual relationship between scanned activity and actual behavior and mental processesactual behavior and mental processes – Evidence about correlation and causation in fMRIEvidence about correlation and causation in fMRI researchresearch
  62. 62. 3 | Thinking Critically:Thinking Critically: What Can fMRI Tell Us aboutWhat Can fMRI Tell Us about Behavior and Mental Processes?Behavior and Mental Processes? (cont(cont’d.)’d.) • What conclusions are most reasonable?What conclusions are most reasonable? – Unlikely to explain how the brain creates behaviorUnlikely to explain how the brain creates behavior and mental processes.and mental processes. – Careful analysis of fMRICareful analysis of fMRI’s value is important.’s value is important. Back to Linked Exercises
  63. 63. 3 | Focus on Research Methods: Manipulating Genes in Animal Models of Human Disease • What was the researchers’ question? – Are the proteins that are found in plaques and tangles the cause of Alzheimer’s disease? • How did the researchers answer the question? – Inserted a gene for a mutant form of beta-amyloid precursor protein into mice.
  64. 64. 3 | Focus on Research Methods: Manipulating Genes (cont’d) • What did the researchers find? – Mice showed memory impairments and developed plaques, no tangles. – Plaques and tangles did appear in transgenic mice with faulty tau, but cannot be the main cause of Alzheimer’s. Human brains with Alzheimer’s disease (bottom row) and those without it.
  65. 65. 3 | Focus on Research Methods: Manipulating Genes (cont’d) • What do the results mean? – Transgenic mice can be used to evaluate the roles of mutations in proteins in causing Alzheimer’s disease. • What do we still need to know? – Challenge is to use animal models to develop and test effective treatments for humans. Back to Linked ExercisesBack to Techniques for Studying the Brain
  66. 66. 3 | 6 In Class Writing Exercises • Place one at the start of your presentation. • Have your students write for a minute or two about the quote on the slide. • This will help them center themselves on the topic to be covered in class. • You may wish to use their responses to generate class discussion. The following slides may be used as advance organizers for the topics in this unit.
  67. 67. 3 | In Class Writing Exercise:: Human action can be modified to some extent, but human nature cannot be changed. Abraham Lincoln
  68. 68. 3 | In Class Writing Exercise:: Every man must do his own growing no matter how tall his grandfather was. L.J. Peter
  69. 69. 3 | In Class Writing Exercise:: Brain and brain, what is brain?Brain and brain, what is brain? ——Kara, an EymorgKara, an Eymorg ((Star TrekStar Trek:: SpockSpock’s Brain’s Brain)) Back to Synapses

×