PSY 260 week7

Binding Memory Context

• Binding content (semantic) to context (episodic) is done by the hippocampus.

• Provides a framework for interpreting and organizing new events or information.

• Increases accuracy of future predictions.

• Concepts are encoded as specific combinations of sensory, motor, and modality-specific features (social, language, emotion).

Semantic and Episodic Memory

Squire’s Model of Long-Term Memory

• Endel Tulving (1927-2023) was a cognitive psychologist at UofT.

• Distinguished between episodic and semantic memory.

• Defined episodic memory as "mental time travel," allowing reflection and self-location in past experiences.

• Memories for specific events are tied to the time and place information was acquired.

Semantic Memory

• Involves general world knowledge that is stable and commonly shared.

• The distinction between episodic and semantic memory was established by Tulving in 1972.

• Both types are conscious and declarative forms of memory.

• Examples of semantic memory include common knowledge such as the capitals of countries.

Representation Types

• Different classes of representations can be modality-dependent.

• Information categorization depends on how it is valued or used; e.g., the sensory nature of the term "Paris" vs. the motor aspect of "Baseball."

Conceptual Knowledge and Memory Benefits

• Voss et al. (1980): Research with baseball experts vs. non-experts showed that more conceptual knowledge led to better memory for information overall.

Semantic Memory Networks

Hub and Spokes Model

• Semantic memory stored in large, distributed networks of associated concepts and ideas, enhancing recall.

• Hubs serve as central concepts, while spokes represent related ideas.

• More associations allow for faster retrieval and better outcome predictions.

Activation of Concepts

• Activation of one concept spreads to related concepts, enhancing semantic interconnectivity (e.g., banana leads to apple/orange).

Episodic Memory

• A collection of personal experiences that include context such as who, what, where, when.

• Contextual details act as cues to reactivate the entire memory trace, supported by neuroimaging studies.

• Strength of memory increases with repeated exposure; episodic memory can fade over time with frequent revisits.

Development of Memory Types

• Episodic memories may develop after sufficient semantic memories are formed.

• Hyperthymesia: Extremely detailed episodic memories; hyperphantasia: Vivid visual imagery in memory.

• Severely Deficient Autobiographical Memory (SDAM): Poor or no visual imagery (aphantasia).

Age-Related Trends in Memory Types

• Children tend to have more episodic memories, whereas older adults tend towards semantic memory.

Interaction between Memory Types

• Examples show how semantic understanding is crucial for recalling episodic memories (e.g., understanding graduation is essential to recall a graduation ceremony).

• Repeated episodic encounters can lead to semantic memory formation (e.g., similar experiences leading to a general concept of "cats").

Animal Models of Memory

Research in Rodents

• Semantic memories in rodents can be assessed using radial arm mazes to demonstrate their flexible use of memory.

• Episodic memory assessed through rats remembering names of baited arms.

Scrub Jays and "Episodic-Like" Memory

• Scrub jays cache food in specific locations and prefer fresh food based on context.

Memory Processes

Encoding, Consolidation, and Retrieval

• Encoding: Initial storage into memory.

• Storage/Consolidation: Maintaining the stored memory; vulnerable to disruption when recent.

• Retrieval: Accessing stored memories for conscious processing.

Encoding Effectiveness

• Deeper processing enhances memory retrieval (Levels of Processing Framework).

• Different levels of processing: structural, phonemic, and semantic.

The Role of Sleep in Memory

• Sleep aids in memory consolidation, integrating new memories with existing knowledge and enhancing performance on learned tasks.

Memory Reconsolidation

• Memories become labile each time they are recalled and can be modified with new information.

Retrieval Methodologies

• Accessing memories involves recognition (easier) and recall (active retrieval).

• More cues enhance memory recall effectiveness.

Testing to Enhance Memory

• Testing effect: Active retrieval strengthens long-term memory better than mere re-reading.

• Experimental data: Remembering through testing leads to improved retention compared to re-reading.

Neuroanatomy of Memory

Cerebral Cortex and Semantic Memory

• Semantic memories are stored in a distributed manner across the cerebral cortex.

• Different cortices (sensory and association) are responsible for linking sensory information and semantic categories.

Frontal Cortex in Memory Processing

• The frontal cortex organizes and retrieves memories while inhibiting irrelevant ones to avoid interference.

Medial Temporal Lobes (MTL) and Memory

• Consolidation largely relies on the MTL, which includes the hippocampus.

• The hippocampus converts short-term to long-term memory, supporting initial memory retrieval.

Theories of Memory Consolidation

Standard Consolidation Theory

• Suggests the cortex gradually becomes independent of the MTL for older memories.

Multiple Trace Theory

• Proposes that the MTL organizes semantic facts into episodic memories; true episodic memories rely on MTL and hippocampus even for retrieval.

Long-Term Potentiation (LTP) in the Hippocampus

• Establishes how synaptic changes occur when new episodic memories are formed.