exam 2

• What is aplysia californica?


  sea slug
• Why do we study aplysia?


  1. they have a small nervous system

  2. their neurons are large

  3. there is little variation between animals (so they can label neurons)

  4. We can fully understand learning and memory
• What is habituation?


  response to a stimuls decreases with repeated exposure, ex: you get used to it
• What is sensitization?


  response to a stimulus increases with repeated exposure or with exposure to a different stimulus, ex: it gets more annoying/painful over time
• How do we measure habituation and sensitization in aplysia?


  gill withdrawal reflex
• T/F Spaced training produces no significant difference in the duration of memory.


  false, spaced training enhances memory and increases duration
• Why would a creature need to habituate or sensitize to its environment?


  precautionary principle: nervous systems assume danger first rather than be caught unaware

  
  

  there is a cost to being so cautious; response lessens overtime if animal deems a stimuli isn't dangerous (or increases if the stimuli is dangerous)
• What is the significance of Aplysia's abdominal ganglion?


  nervous system is across the entire creature- not just the head, we can pinpoint the exact neurons that cause the gill reflex and study them
• Explain the gill withdrawal circuit operates.


  sensory neuron is directly connected to the motor neuron, which activates the gill withdrawal response when activated

  - habituation occurs when the sensory neuron releases less neurotransmitters onto the motor nueron, cuasing it to fire less and lesssen the gill withdrawal response

  - sensitization requires an additional modulatory interneuron which forms a synapse on the axon terminal of the sensory neuron, when shock occurs, the modulatory interneuron releases serotonin on the siphon sensory neuron terminal which causes a much larger response =in the motor neuron/gill withdrawal response
• Short term habituation is mediated by ____________? explain this concept.


  synaptic depression; decrease in neurotransmitter release

  
  

  connection between siphon sensor neuron and motor neuron gets weaker

  - less able to depolarize the motor neuron after repeated exposure to stimuli
• Explain how dis-habituation occurs


  after intense stimulation the gill withdrawal reflex dis-habituates, synaptic depression is reversed
• What makes dishabituation different from sensitization?


  sensitization is an increase in the baseline response; disbaituation brings the habituated response back to baseline
• What is the short term habituation hypothesis?


  the sites on the presynaptic membrane are designed to be released, light stimulation silences release sites but they are immediately reactivated with strong stimulation
• long term habituation is mediated by ________? explain this concept


  synaptic depression; depolarization of motor neurons gets smaller over time, the number of axon branches and terminals are reduced, active zones on axons shrink, total number of synapses in abdominal ganglia dramatically decrease
• short term habituation is mediated by _______ changes. Long term habituation is mediated by _______ changes.

  functional, structural
• What induces long term habituation?


  protein synthesis induces the structural changes
• What is short term sensitization mediated by? explain


  synaptic facilitation: this means change occurs in the function, increased action potential duration means more neurotransmitter release
• long term sensitization is mediated by ______?


  structural changes in the siphon sensory neuron

  - increase in synaptic contacts

  -depends on protein synthesis
• What is pavlovian conditioning?


  a form of associative learning about the relationship between otherwise neutral stimuli in the environment and the motivationally salient stimuli and outcomes they predict
• What is the conditioned stimulus?


  neutral sensory cue that does not elicit a major response when presented alone
• What is the unconditioned stimulus?


  a cue, event or outcome that can elicit a behavioral response when presented alone
• What is the conditioned response?


  learned response elicited by the conditioned stimulus once it has been paired with the unconditioned stimulus
• What is the unconditioned response?


  the behavior elicited by the unconditioned stimulus
• basic procedure of eye blink conditioning....

  look up
• In order for learning to occur, the unconditioned stimulus must be_____?


  surprising or unexpected
• Describe the rescorla-wagner model of learning


  new learning will result if the US differs from what is expected
• explain the blocking effect.


  when the unconditioned stimulus is already expected, no learning occurs
• where does the eye blink conditioning occur in the brain?


  the cerebellum
• explain the cerebellum's role in the CR and UR


  when the cerebellum is lesioned in rabbits, the CR does not continue while the UR does, this means that even though they are the same motor response, they are not supported by the same brain mechanisms
• T/F the facial motor nucleus impacts learning

  false, it impacts performance
• What is a reflex?


  an involuntary motor reaction that occurs in response to a particular sensory stimulus, simple neural circuit: sensory neuron directly connected to motor neuron (monosynaptic)
• Know the anatomy of the cerebellum and be able to describe its function.


  a. parallel fibers: granule cell axons that contact purkinje cells

  
  

  b. climbing fibers: axon that climbs from cells in olivary nucleus, carries information about the US to the purkinje cells

  
  

  c. mossy fivers: axons that rise from cells in the pontine nucleus, carries information about CS to purkinje cells via granule cells
• What role do prukinje cells play in eye blink conditioning?


  presentation of the CS causes purkinje cells to decrease the rate at which they fire action potentials; disinhibit the eye blink CR pathway
• Explain how LTD occurs at purkinje synapses.


  1. As a result of intense stimulation, the synapses at granule cells andpurkinje cells get weaker.

  
  

  2. Adult purkinje cells don't have NMDA so they respond differently toglutamate

  
  

  3. mGluR (metabotropic glutamate receptor) activates G protein to start theprocess of LTD

  -Strong activation means more glutamate which means more LTD

  
  

  4. LTD is mediated by a decrease in AMPA receptor function at parallel fibersynapses on purkinje cells

  -Structural changes
• Does LTD inhibit purkinje cells? explain


  yes, inhibitory and excitatory synapses compete to control the purkinje cells and when LTD occurs at the excitatory synapses, inhibitory synapses win
• What are the four criteria of assessing plasticity?

  1. detectability

  2. alteration prior to learning

  3. alteration following learning

  4. mimicry: be able to create a false memory
• What do the olivary and pontine nuclei do?


  olivary: carries information about US to prukinje cells via climbing fibers

  
  

  pontine: sends auditory CS information via granule cells to purkinje cells
• What is emotion? How are emotion and mood different?


  1. psychological state triggered by external stimuli that rapidly organizes and implements a complex and coordinated response that is appropriate and adaptive

  
  

  2. mood is what you return to (not externally triggered)
• What are two models of emotion that William James theorizes?

  1. emotions are elemental and cannot be broken down; they have specific brain areas for each one

  
  

  2. emotions are like soup with many ingredients and no special brain centers: combination of many things
• What are the components of the constructionist definition of emotion?


  1. core affect

  2. conceptual knowledge

  3. interoceptive

  4. exteroceptive perception