PS352 Psychology Of Learning - Notes

Neural Basis of Learning

Course Information

  • Course: PS352 Psychology Of Learning
  • Instructor: Prof. Sean Commins
  • Email: Sean.Commins@mu.ie
  • Location: SF20 John Hume Building

Course Structure

  • Weeks 1-2: Prof. Sean Commins
  • Weeks 3-10: Prof. Bryan Roche

Topics Covered

  • Neural basis of learning
  • Learning in invertebrates
    • Habituation
    • Sensitization
    • Classical conditioning
  • Learning in vertebrates
    • Long-term potentiation (LTP)
  • Re-visiting place cells and the neural code
  • The Behavioural Approach to Learning
  • Reinforcement, extinction, inhibition & aversive control
  • Operants, Shaping & Schedules
  • The Discriminated Operant & Stimulus Equivalence
  • Relational Frame Theory

Required Readings

  • Commins, S. (2018). Behavioural Neuroscience. CUP. (Chapters 5, 6, 7, and 14)
  • Jeffery, K. (2003). The Neurobiology of Spatial Behaviour. Oxford University Press.
  • All slides and extra reading material will be available on Moodle.

Learning in Invertebrates

Non-Associative Learning

  • Change in behavioral response over time to a single stimulus.
  • Two types:
    1. Habituation
    2. Sensitization
Habituation
  • Definition: A form of learning in which a response to a stimulus weakens with repeated presentation.
  • Example: Getting used to the ringing of a telephone.
Sensitization
  • Definition: Increase of a response due to the presentation of a novel, often noxious stimulus.
  • Example: Becoming more sensitive to sounds at night during a blackout.

Associative Learning

  • Associations are formed between events.
  • Two types:
    1. Classical Conditioning
    2. Instrumental Learning
  • Example: Associating a phone number with a person.
Classical Conditioning
  • Described by Pavlov.
  • Associating a stimulus that evokes a measurable response with a second stimulus that normally doesn’t evoke this response.
  • Example: Bell and meat (Pavlov's dog experiment)
    • Before conditioning:
      • Food (UCS) leads to salivation (UCR).
      • Bell has no response.
    • During conditioning:
      • Bell + Food (UCS) leads to salivation (UCR).
    • After conditioning:
      • Bell (CS) leads to salivation (CR).
  • Timing:
    • Critical for conditioning to occur.
    • The US (Bell) and CS (Meat) should be presented simultaneously or with a short interval where the CS (Bell) precedes the US (Meat).
    • If the interval lengthens, the effect may disappear.
Instrumental Learning
  • Developed by Thorndike.
  • Associating a response with a meaningful stimulus, such as a reward or punishment.
  • Example: Exams

Why Study Learning in Invertebrates?

  • Small nervous system
  • Large neurons
  • Simple genetic make-up

Aplysia (Sea Slug)

  • Used for studying learning.
  • Anatomy: Tail, Mantle, Siphon, Gill, Head.
  • Siphon: Expels waste and helps the animal to move.
  • Gill: Used for breathing.
Habituation in Aplysia
  • If you lightly touch the tail of the Aplysia, it immediately draws its tail away.
  • If you continue to touch the tail in the same spot, the Aplysia will stop contracting its tail.
  • It has habituated to the touch.
  • Siphon squirts water, and the gill withdraws.
  • If you continue to squirt water, the gill stops withdrawing.
Neural Level of Habituation
  • Behavioral change must be reflected at the neural level.
  • Involves sensory and motor neurons.
  • Eventually, the response diminishes.
Where Does Habituation Take Place?
  • Not at the input stage (sensory neuron).
  • Action potentials do not diminish with continued stimulation.
  • Not at the output stage (motor neuron).
  • Contractions do not diminish with continued stimulation.
  • Habituation takes place at the sensory/motor neuron junction.
Molecular Level of Habituation
  • Initial strong gill withdrawal response.
  • With time and habituation:
    • Less Ca++Ca^{++} channels open.
    • Less Ca++Ca^{++} influx.
    • Less neurotransmitter (Glutamate) released.
    • Less depolarization.
    • Weaker gill withdrawal response.
    • The animal has learned/habituated.
Summary
  • Simple model of learning (habituation) can be understood not just at the behavioral, but also at cellular and molecular levels.