Description

1.

Synaptic Strength (Long-Term Potentiation – LTP)

• Type: Chemical and structural

• What it is: Enhanced efficiency of synaptic transmission between neurons.

• Mechanism:

  • When two neurons repeatedly activate together, glutamate release activates NMDA and AMPA receptors, allowing calcium influx.

  • This triggers a cascade that increases the number and sensitivity of synaptic receptors, especially AMPA receptors.

  • Results in a stronger, more responsive synapse.

• Duration: Minutes to decades (if reinforced).

• Key regions: Hippocampus (early encoding), cortex (long-term storage).

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2.

Structural Changes in Neurons

• Type: Morphological (physical structure)

• What it is: Formation or elimination of dendritic spines and even whole synapses.

• Mechanism: Neurons that “fire together, wire together” — memory formation leads to new synaptic connections, increased dendritic complexity, or pruning of irrelevant pathways.

• Implication: You literally rewire your brain every time you form a lasting memory.

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3.

Gene Expression and Protein Synthesis

• Type: Molecular

• What it is: Long-term memories require the synthesis of new proteins.

• Mechanism:

  • Calcium influx activates transcription factors (e.g., CREB).

  • These trigger gene expression for proteins needed to build/maintain synapses.

• Blocking protein synthesis = memory formation fails.

• Duration: Supports maintenance over time (days to years).