Learning and Memory

Introduction to Learning and Memory, Part I

Outline

  • Today

    • Current Taxonomy of Memory Systems

      • Short-Term/Working Memory

      • Long-Term Memory

        • Declarative versus Nondeclarative

    • Contributions of Patient H.M. and others to understanding memory in the brain

  • Tuesday

    • Overview of major CN findings for:

      • Declarative

      • Nondeclarative

      • Working Memory

Study of Memory

  • Key components:

    • Understanding memory:

      • Where it is stored and which brain systems are involved (systems problem)

    • How memory is stored (molecular problem)

  • Focus of this course: Systems problem

    • Investigation into what is happening at various memory stages

Relationship Between Learning and Memory

  • Three stages of memory:

    • Encoding:

      • Acquisition and Consolidation

    • Storage

    • Retrieval:

      • The process of retrieving information leads to answers in tests

Current Taxonomy of Memory Systems

  • Types of Memory:

    • Long-Term Memory

    • Short-Term Memory

    • Sensory Memory

      • Short-term/Working Memory

        • Declarative Memory (explicit, facts, events)

          • Episodic Memory

          • Semantic Memory

        • Nondeclarative Memory (implicit, skills, conditioning, etc.)

          • Procedural Memory

          • Perceptual Memory

          • Classical Conditioning

          • Nonassociative Learning

Short-term Memory

  • Sensory Memory

    • Involves brief observation of stimuli

    • Types:

      • Echoic Memory: Auditory stimuli lasting seconds

      • Iconic Memory: Visual stimuli lasting milliseconds

  • Duration: Persists from milliseconds to minutes

  • Limited Capacity: 7 ± 2 units of information

    • Originated from Atkinson and Shiffrin's model

Working Memory

  • Temporary maintenance and manipulation of information

  • Necessary for achieving short-term goals

  • Baddeley’s model (1974):

    • Relates to short-term memory capacity

Contributions of Patient H.M. and Others

  • Historical Context of Memory Study

    • Early 20th century: Memory seen as a unified process

    • Now understood as different brain regions contributing uniquely to various types of memory

Case Study: Patient H.M.

  • Suffered from profound impairments in forming new memories following surgery

  • Illustrates important memory loss dichotomy

  • Retained normal short-term memory but could not transfer to long-term

  • Could learn motor skills but lacked memory of learned tasks

Memory Impairments in H.M.

  • Normal short-term memory abilities

    • Can rehearse digits but forget if attention shifts

  • Ability to learn new skills: Examples include mirror-drawing task

    • Significant retention over multiple trials

  • Possible preservation of some semantic learning

Conclusions on H.M.

  • Capacities of H.M. included perceptual priming behaviors

  • Nondeclarative memory emerged intact in amnesics like H.M.

  • Learning and memory in amnesic patients show independence from medial temporal lobe

Double Dissociation: Declarative vs. Nondeclarative Memory

  • Long-standing absence of double dissociation concept in literature resolved by Gabrieli et al. (1995) with case study of patient M.S.

  • M.S. exhibit differences in losses pertaining to declarative and nondeclarative memory based on damage to brain regions

Short-Term/Working Memory vs. Long-Term Memory

  • Case study of Patient K.F. showing unique patterns of memory impairment

  • Patterns of impairment challenge traditional models of memory

  • Highlight contrasts between short-term and long-term memory processes

Aside: Clive Wearing

  • Known for his profound amnesia due to a brain infection, reinforcing memory studies derived from unique patient experiences