Overview
This lecture explains how different parts of the brain contribute to memory formation, storage, and retrieval, with emphasis on the amygdala, hippocampus, cerebellum, and prefrontal cortex.
Early Memory Research and Engram
- Karl Lashley searched for the engram, the physical trace of memory, by lesioning animal brains.
- Lashley’s equipotentiality hypothesis suggests that if one brain area is damaged, another part can serve the same memory function.
- Modern research finds that memories are distributed but certain areas are especially important for specific memory types.
Main Brain Structures Involved in Memory
- The amygdala, hippocampus, cerebellum, and prefrontal cortex are identified as key memory centers.
- Each brain area is linked to different types of memory and memory processes.
The Amygdala
- The amygdala is responsible for processing emotions, especially fear, and is involved in fear memories.
- It helps store emotional memories, influenced by stress hormones.
- The amygdala is crucial for memory consolidation when experiences are emotional.
The Hippocampus
- The hippocampus is essential for declarative (facts, events) and spatial memories.
- Damage to the hippocampus impairs the ability to form new declarative memories but not old ones.
- It helps transfer new learning into long-term memory and connects memories to meanings.
The Cerebellum and Prefrontal Cortex
- The cerebellum is involved in implicit (procedural) memories like skills and conditioning.
- Damage to the cerebellum disrupts learning of conditioned responses.
- The prefrontal cortex is active during semantic tasks and is involved in both encoding and retrieval of information.
Neurotransmitters and Memory
- Neurotransmitters like epinephrine, dopamine, serotonin, glutamate, and acetylcholine are vital for memory processes.
- Communication between neurons via neurotransmitters is necessary for memory formation and consolidation.
- Strong emotions increase neurotransmitter release, strengthening memory (arousal theory).
Flashbulb and False Memories
- Flashbulb memories are vivid recollections of significant events, usually with strong emotional content.
- Even flashbulb memories can become inaccurate over time due to memory reconstruction.
- False memories can occur when people recall events that did not happen.
Key Terms & Definitions
- Engram — the physical trace or location of a memory in the brain.
- Equipotentiality hypothesis — the idea that one area of the brain can compensate for another in memory function.
- Memory consolidation — the process of stabilizing a memory into long-term storage.
- Declarative memory — memory for facts and events.
- Procedural memory — memory for skills and actions.
- Flashbulb memory — a highly detailed, emotional memory of an unusual event.
- False memory — remembering events that never occurred.
Action Items / Next Steps
- Review the roles of the amygdala, hippocampus, cerebellum, and prefrontal cortex in memory.
- Reflect on personal flashbulb memories and consider their accuracy.
- Prepare for questions on how neurotransmitters and brain regions interact in memory.