Memory Storage

Brain Structures & Memory Processing

                             ┌─────────────────────────┐
                             │    BRAIN & MEMORY       │
                             └────────────┬────────────┘
                                          │
       ┌──────────────────────────────────┼──────────────────────────────────┐
       ▼                                  ▼                                  ▼
EXPLICIT MEMORY                    IMPLICIT MEMORY                   EMOTIONAL MEMORY
(Frontal Lobes + Hippocampus)      (Cerebellum + Basal Ganglia)      (Amygdala)
   • Conscious facts & events         • Conditioned reflexes            • Stress / Excitement
   • Temporary storage                • Motor movement / skills         • Flashbulb memories
   • Sends to cortex                  • Formed without hippocampus      • Sharpened focus

1. Explicit Memory Formation

• Frontal Lobes & Hippocampus: Process and temporarily store explicit (declarative) memories.

• Memory Consolidation: The process of converting memories into long-term storage.

  • How it Works: The hippocampus processes sensory details into short-term storage, then transfers them to the cortex for long-term storage.

  • Role of Sleep: Sleep strongly supports consolidation. The brain replays the day’s experiences and transfers them to the cortex. Spaced repetition increases sleep-induced consolidation.

• Brain Damage Insight: Damage to the hippocampus impairs explicit memory formation, but a person can still create and retain implicit memories.

2. Implicit Memory Formation

• Cerebellum: Key for developing classically conditioned reflexes. (Damage prevents forming certain conditioned responses).

• Basal Ganglia: Deep brain structures involved in forming implicit memories for motor movements and procedural skills.

• Infantile Amnesia: Adults' inability to recall episodic memories from before age 4.

  • Causes: An undeveloped hippocampus + a lack of verbal skills required to encode early memories.

3. Emotion-Related Memory Formation

• Amygdala: Triggered by stress or excitement to sharpen memory processing.

  • The Stress Response Chain:

    $\text{Stress/Excitement} \longrightarrow \text{Stress Hormones Released} \longrightarrow \text{Glucose Sent to Brain} \longrightarrow \text{Amygdala Activated} \longrightarrow \text{Memory Focus Sharpened}$

• Key Phenomena:

  • Lingering Emotions: Emotional feelings can persist even without conscious awareness of the event that caused them.

  • Prioritization: The brain prioritizes important events and forgets minor background details.

  • Flashbulb Memories: Vivid, explicit memories of emotionally significant, shocking, or exciting events.

    • Mechanism: Stronger emotional impact leads to repeated mental rehearsal, making these memories easier to recall.

Neural Mechanisms: Synapses & Long-Term Potentiation (LTP)

Synapses

• Definition: The junctions where nerve cells communicate using neurotransmitters.

• Role: Synapses are the primary physical site where learning and brain changes take place.

Long-Term Potentiation (LTP)

• Definition: The strengthening of synaptic connections through repeated activity; considered the primary biological foundation for learning and memory.

• How Learning Changes the Synapse: Experience and learning cause neurotransmitters to be released more easily, fostering the growth of new synaptic connections.