Apoptosis, Synaptic Pruning & Brain Development

Apoptosis “Polite Cell Death” - A programmed control process where cells? The cell does what in the process? It sends signals where?

• Definition:

  • A programmed, controlled process where cells intentionally die in an organized way.
    

• Process:

  • The cell “packs up its bags” — it shrinks and neatly packages its internal materials.

  • It sends signals to microglial cells (the brain’s cleanup crew) to come “eat” or remove it safely.

Apoptosis “Polite Cell Death” - Why is it polite? Clean? Prevents? Keeps? If it didn’t do this, the cell would what?

• Why it’s polite:

  • The cell cleans up after itself instead of bursting and spilling its contents.

  • Prevents inflammation and damage to nearby neurons.

  • Keeps the environment safe and healthy for other cells.
    
    

• If it didn’t do this:

  • The cell would die in a messy, uncontrolled way that could harm surrounding neurons.
    
    

Synaptic Pruning – “Use It or Lose It” - the brain removes unnecessary what? The fine-tuning makes communication?

• Definition:

  • The brain removes extra or unnecessary synaptic connections between neurons.

  • This fine-tuning makes communication between neurons more efficient.

Synaptic Pruning – “Use It or Lose It” - The brain starts off? Strengthens pathways that are used often? Based on what?

• Purpose:

  • The brain starts off overconnected and gradually trims back the unused connections.

  • Strengthens pathways that are used often — weakens or eliminates ones that aren’t.

  • Based on experiences and activity after birth.

Synaptic Pruning – “Use It or Lose It” - Neurons that fire together, what? This means neurons that activate…? If two neurons are not firing together, the brain…?

• Key phrase:

  • “Neurons that fire together, wire together.”

  • Meaning: Neurons that activate at the same time stay connected and form networks.

  • If two neurons are not firing together, the brain assumes the connection isn’t useful → it prunes it away.

✂ Fixing Wiring Mistakes (fire together, wire together) - Analogy: Like clapping too early at a concert…? Wizard of Oz analogy - The neuron’s mistaken axon branch retracts like…

• Analogy:

  • Like clapping too early at a concert — the neuron realizes it “misfired” and corrects itself.
    

• Wizard of Oz analogy:

  • The neuron’s mistaken axon branch retracts like the Wicked Witch’s striped legs pulling back under the house.

✂ Fixing Wiring Mistakes - prevents incorrect blank? Keeps neural networks…? The neuron doesn’t die…?

• Purpose:

  • Prevents incorrect wiring.

  • Keeps neural networks organized by function.
    
    

• Important note:

  • The neuron doesn’t die — it just disconnects that one wrong synapse.

🧩 Prefrontal Cortex Development – “The Last to Mature” - located where? Responsible for decision making, …?

• Location:

  • Front part of the brain, behind the forehead.
    

• Role:

  • Responsible for decision-making, planning, judgment, impulse control, and emotional regulation.

🧩 Prefrontal Cortex Development – “The Last to Mature” - One of the last brain regions…? This explains why teenagers…? As myelination finishes in the prefrontal cortex, people become…?

• Development:

  • One of the last brain regions to fully mature — finishes in the mid-20s.

  • This explains why teenagers can be impulsive or emotional — their “braking system” isn’t fully wired yet.
    
    

• Connection to Myelination:

As myelination finishes in the prefrontal cortex, people become better at thinking ahead, making decisions, and controlling impulses.