Types of Memory

Memory

Lecture Overview

• Learning & Memory Lecture 1: Focuses on types of memory, classical conditioning, and instrumental learning by Dr. Simon Trent (LSC-20076).

• Organized into three main parts:

  1. Types of memory, models of short-term and long-term memories

  2. Classical conditioning

  3. Instrumental learning

Characteristics of Memory

Short-Term vs Long-Term Memory

Both short-term and long-term memories share several characteristics:

• Time of Storage:

  • Short-term memory (STM): Immediate, occurs right after acquisition.

  • Long-term memory (LTM): Later, as it must be transferred from STM to LTM through a process of consolidation.

• Duration:

  • STM: Lasts from seconds up to hours.

  • LTM: Retained from days to years.

• Capacity:

  • STM: Limited capacity.

  • LTM: Very large capacity.

• Retrieval Time:

  • STM: Rapid retrieval of information.

  • LTM: Slower retrieval, with ingrained memories being accessed more quickly.

• Inability to Retrieve (Forgetting):

  • STM: Information is usually permanently forgotten or fades quickly unless consciously consolidated.

  • LTM: Memory is often only transiently inaccessible; once consolidated, it tends to have relatively stable traces.

• Mechanism of Storage:

  • STM: Involves transient changes in the functions of existing synapses, like alterations in neurotransmitter release.

  • LTM: Involves relatively permanent changes, including the formation of new synapses and synthesis of new proteins.

Attention and Memory

• The concept of the "intentional spotlight" suggests our attention shifts in such a way that stimuli falling within its focus are preferentially processed.

The Atkinson-Shiffrin Model (1968)

• This model outlines the flow of information from sensory input to short and long-term memories, emphasizing the roles of:

  • Maintenance rehearsal: Keeping information in STM.

  • Attention: Focus for encoding.

  • Encoding: Transition from sensory to short-term memory.

  • Retrieval: The mechanism involved for accessing information.

Short-Term Memory (STM) Processing Strategies

• To improve memory retention, various effortful processing strategies can be employed:

  1. Repetition: Rehearse information aloud.

  2. Chunking: Group information into smaller, manageable units (e.g. 123456 becomes 123-456).

  3. Mnemonics: Use of images, acronyms, or peg-words to aid recall.

  4. Hierarchies/Categorization: Organize information into structured categories.

  5. Distributed Practice: Space out learning sessions over time for better retention.

  6. Deep Processing: Engage with the material meaningfully, relating it personally to enhance recall.

Understanding Long-Term Memory

• Long-term memory is likened to a network rather than a singular storage space, where memories are distributed across overlapping neural networks rather than stored like files on a hard drive.

• The brain's storage capacity for long-term memory is effectively limitless, and memory retrieval involves complex neural processes.

Models and Types of Long-Term Memory

• Long-term memory is divided between:

  • Declarative (Explicit) Memory: Involves facts and events.

    • Episodic Memory: Personal experiences.

    • Semantic Memory: General knowledge and facts.

  • Non-Declarative (Implicit) Memory: Involves skills and behaviors.

    • Procedural Memory: Knowledge of how to perform tasks.

    • Priming and Associative Learning: Influences behavior based on prior experiences.

Current Perspectives on Memory

• Memory systems are continuously refined, with current models distinguishing between short-term (working) and long-term memory:

  1. Declarative Memory (explicit) - encompasses episodic and semantic.

  2. Non-Declarative Memory (implicit) - includes procedural skills, priming, and simple classical conditioning.

Brain Regions Involved in Memory

• Short-term memory primarily involves the prefrontal cortex, while long-term memory tasks engage various brain regions including:

  • Hippocampus: Critical for forming new long-term memories.

  • Neocortex: Involved in high-level processing and memory consolidation.

  • Amygdala: Plays a role in emotional memory.

  • Cerebellum: Contributes to procedural memory and motor control.

This comprehensive overview encapsulates key ideas about types of memory, processes involved in encoding and retrieval, and the neurological underpinnings of memory storage.