Brain _ Behavior by rt3463df

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									Brain & Behavior




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Goals for Lecture & Readings
• Understand the mechanisms of
  neural communication
• Understand the form and function of
  the nervous system




                                        2
Phineas Gage
    • 1848
    • Railway worker
    • Tamping iron blew
      through his head
    • Memory and movement
      intact, could learn new
      things
    • But, personality changed

                          3
Phineas Gage
  • 1980s
  • Computer modelling
    shows path of rod
  • Damaged ventromedial
    frontal lobe
     • Brain region linked to
       personality


                                4
       “Biopsychology”
• Biological approach to the study of
  psychology

• Various approaches to understand
  links between nervous system and
  behavior


                                        5
Characteristics of Biopsychology
  • Humans & nonhumans subjects
  • Experiments and case studies
  • Basic and applied research




                                   6
Divisions of Biopsychology
1. Physiological Psychology
  •   Manipulate nervous system (surgery,
      chemicals); theories of neural control of
      behavior
2. Psychopharmacology
  •   Effects of drugs on neural activity and
      behavior
3. Neuropsychology
  •   Study behavioral deficits produced by brain
      damage; often applied
                                                    7
 Divisions of Biopsychology
4. Psychophysiology
  •   Record physiological responses to
      understand relation between physiology and
      psychology

5. Comparative Psychology
  •   Behavior of different species; focus on
      genetics, evolution, function



                                                   8
  Building Blocks of Nervous
            System
• Neurons
   • Specialized nerve cells
   • Send/receive nerve impulses
   • Sensory, motor, interneurons
• Neurons have a right-hand man, called
  glial cells
   • hold neurons in place and provide
     nutrients
   • Outnumber neurons 10:1               9
                Neurons
• Three basic parts:
   • Cell body (soma)
      • Metabolic centre, genetic material,
        etc…
   • Dendrites
      • Specialized fibres for receiving info
   • Axon
      • Conducts messages away from cell
        body                                    10
Also, Node of Ranvier   Terminal buttons   11
               Neurons
• Neuron fires when stimulated
  – Heat
  – Light
  – Pressure
  – Other neurons
• The impulse is called an action potential


                                          12
Electrical Activity of a Resting
            Neuron
• Membrane Potential:
  • Difference in electrical charge between
    inside and outside of cell
• Resting Potential:
  • -70 mV
  • Lots of Na(+) ions outside cell
  • Lots of protein(-) molecules inside cell


                                               13
          When a Neuron is
           Stimulated…
• Stimulation causes
  distribution of
  particles to change
• Na(+) flows in
   • Attracted to
     protein(-)
• Inside now (+)
  relative to outside

                             14
        Neural Conduction
• Action Potential:
   • Massive, brief reversal of membrane
     potential from –70 to +50 mV

• After an action potential, neuron has to
  recharge, so to speak
   • K(+) pumped out of cell, (-) charge
     restored
   • Refractory period – neuron cannot fire
     again during this process


                                              15
Myelinated Axons

        • Myelin is fatty tissue
        • Faster conduction
        • Action potential
          “jump” from one Node
          of Ranvier to the next
        • Multiple Sclerosis –
          myelin sheath
          destroyed

                           16
   From One Neuron to the
           Next
• Synapse:
  • The site of adjacent neurons
  • “Synapse” - Greek word for “gap”
     • (Every mall in Athens has a store called
       “The Synapse”)
  • Action potentials at terminal buttons
    cause release of chemical
    neurotransmitters
  • Neurotransmitters bind to sites on
    adjacent neurons and thereby induce
    electrochemical changes in them
                                                  17
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       Neurotransmitters
• When they bind to an adjacent
  neuron, they cause chemical
  reactions
• Excitatory neurotransmitters
   • Cause Na(+) to enter cell
   • Makes action potential more likely
   • Makes it more likely the cell will
     send signals to other neurons
                                          19
       Neurotransmitters
• Inhibitory neurotransmitters
   • May cause K(+) to leave the cell, or
     Chloride(-) to enter
   • This makes an action potential less
     likely
       • makes it less likely the cell will
         send signals to other neurons


                                          20
  Some Neurotransmitters
• Acetylcholine
  • Excitatory at synapses involved in
    memory and movements
• Dopamine
  • Excitatory; movement, emotional
    arousal



                                         21
         Effects of Drugs
• Drugs affect behavior and thought by
  influencing the activity of neurons
• Agonists
  • Mimic a particular neurotransmitter
  • Increase activity of neurotransmitter
• Antagonists
  • Inhibits activity of a neurotransmitter


                                              22
        Effects of Drugs
• Nicotine is an agonist for Dopamine
  • Reward and pleasure


• Amphetamines and Cocaine:
  agonists for Dopamine and
  Norepinephrine
  • Reward, pleasure, arousal


                                        23
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     Major Divisions of Nervous
               System
• Central Nervous System
  (CNS):
  • Brain
  • Spinal cord
• Peripheral Nervous
  System (PNS):
  • Somatic Nervous System
  • Autonomic Nervous
    System
                                  25
  Peripheral Nervous System

• Somatic Nervous System:
  • Interacts with external environment
  • Sensory info from receptors (in
    skin, joints, eyes, ears, etc.) to CNS
  • Signals sent back from CNS to
    skeletal muscles
  • Deals largely with voluntary
    actions
                                         26
  Peripheral Nervous System
• Autonomic Nervous System:
  • Involved in regulation of internal
    environment
  • Deals largely with involuntary functions
  • Signals from organs to CNS
  • Signals from CNS to organs
     • Sympathetic nerves
       • Prepare for action
    • Parasympathetic nerves
       • Conserve energy
                                           27
       Central Nervous System
• Spinal Cord
  • Highway for most nerves
  • H-shaped core of gray matter
     • Cell bodies, unmyelinated
       interneurons
  • Surrounding white matter
     • Ascending & descending myelinated
       axons


                                           28
The Brain




            29
The Brain




            30
One More Brain Diagram




                         31
EEG




Measures electrical activity




                        32
              CAT Scan

Computerized Axial
Tomography




                         33
              PET Scan

Positron Emission
Tomography




                         34
                MRI

Magnetic Resonance
Imaging




                      35
  The Brain, Function & Form
• Brainstem
  • Medulla:
    • Tracts that carry signals between
      brain and rest of body
  • Reticular formation:
    • Involved in sleep, attention,
      movement, and various autonomic
      functions


                                          36
  The Brain, Function & Form
• Cerebellum
  • “Little brain”
  • Walking
  • Balance
  • Timing and coordination of
    movements



                                 37
  The Brain, Function & Form
• Thalamus
  • Sensory relay station
  • Info from sensory receptors processed
    and sent to sensory cortex


• Basal Ganglia
  • Surrounds thalamus
  • Deliberate movements
  • Parkinson’s disease
                                            38
  The Brain, Function & Form
• Limbic System
  • Hippocampus
     • memory
  • Amygdala
     • emotion
  • Hypothalamus
     • Motivation; biological drives

                                       39
                   The Brain
• Cerebral Cortex:
  •   Outermost layer of brain
  •   Wrinkled
  •   Many connections to other areas
  •   Frontal cortex complex cognition
  •   Temporal  auditory, language
  •   Occipital  visual
  •   Parietal  sensory stuff

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