Neurodevelopment and Neuroplasticity

Sensitive (Critical) Periods - A short time early in life…? After the window closes: The cortex…? Changes are…? If you try to fix something…? Once the “window” is closed???

• Definition: A short time early in life when the brain learns things more easily.
  
  

• After the window closes:

  • The cortex connections are already established.

  • Changes are harder or incomplete (“not malleable outside the sensitive period”).

  • If you try to fix or retrain something (like vision) later, it won’t reach full capacity.
    
    

Key idea: Once the “window” is closed, experiences have less impact on brain wiring.

Strabismus and Visual Development - A problem with the eye muscles…? Example? Affects about…?

• Definition: A problem with the eye muscles where the eyes don’t align properly.

  • Examples: “lazy eye” (amblyopia), “cross-eyed.”

  • Affects about 5% of infants — a large number.

Strabismus and Visual Development - the brain receives…?  To reduce confusion…? This can cause ocular…?

• Why it matters:

  • The brain receives double, blurry input (double vision).

  • To reduce confusion, the brain suppresses input from one eye.

  • This can cause ocular dominance reorganization, where one eye becomes dominant.

Strabismus and Visual Development - Timing is…? Surgery must be done…? Waiting too long can…? Informs doctors to…?

• Timing is crucial:

  • Surgery must be done early (during the sensitive period).

  • Waiting too long can lead to permanent vision problems or blindness that can’t be corrected later.
    
    

Informs doctors to perform early eye muscle surgery.

Neuroplasticity main idea-  The brain can change it’s…?

Main idea: The brain can change its connections (plasticity), but usually doesn’t make new neurons except in a few areas.

Neuroplasticity Exceptions - Hippocampus: involved in…? Constantly forming…? Low neurogenesis linked…? Striatum: Involved in…? Ventricular zone: Sources of adult stem cells….?

• Exceptions (where neurogenesis happens):

  • Hippocampus:

    • Involved in forming new memories.

    • Constantly forming and pruning neurons.

    • Low neurogenesis linked to depression (due to low BDNF levels).
      
      

  • Striatum:

    • Involved in habit formation and motor patterns.

  • Ventricular Zone:

Source of adult stem cells near ventricles that generate new neurons for these areas.

Neurogenesis in the Adult Brain Concept

Neurogenesis is when the brain makes new neurons. Even adults can grow new brain cells—just not everywhere.

Neurogenesis in the Adult Brain Locations (2)

Where it happens:

1. Hippocampus (dentate gyrus)

   • This part helps with learning and memory.

   • It’s the main place where adults make new neurons.

2. Subventricular zone (SVZ)

   • A layer of cells next to the brain’s fluid-filled spaces.

Neurogenesis and Environment -In humans - Physical activity…? Helps with…? Cognitive activities help too…?

• Physical activity boosts neurogenesis.

• Helps with depression and can prevent dementia.

Cognitive activities (crossword puzzles, mental challenges) help too — but exercise is equally important.

Tumor - abnormal…? may grow slowly or….? can cause headaches…?

• Abnormal, uncontrolled cell growth.

• May grow slowly or quickly; can press on surrounding brain tissue.
  

Can cause headaches, seizures, nausea, or cognitive changes (mental dullness).

Three Main Ways to Classify a Brain Tumor

1. Primary vs. Secondary

   • Primary tumor:

   • Secondary (metastatic) tumor:

2. Benign vs. Malignant

   • Benign:

   • Malignant:

3. Tumor Cell Type (What cell it comes from)

   • Gliomas (from glial cells)

   • Meningiomas (from meninges)

   • Astrocytomas (from astrocytes)

   • Oligodendrogliomas (from oligodendrocytes)

Tumor Symptoms Depend on Location (Pt.1) -

• Sensory areas:

• Motor areas:

• Frontal lobe:

• Sensory areas: Hearing or vision issues.

• Motor areas: Coordination or movement problems.

• Frontal lobe: Personality or behavioral changes.

Tumor Symptoms Depend on Location (Pt.2) -

• Language areas:

• Cerebellum:

• Language areas: Aphasia (trouble producing/understanding speech).

• Cerebellum: Balance and coordination problems.

Encapsulated Tumor - separate from…? Example?

• Separate from healthy tissue, often easier to remove.

Example: Meningioma (between meninges).

Infiltrating Tumor - grows into…? hard to…?

• Grows into healthy tissue with “fingers.”

• Harder to remove completely.

Benign Tumor

Easier to remove; grows slowly

Malignant Tumor - Cancerous…? Remaining cells…?

• Cancerous, spreads, harder to remove.

• Remaining cells can regrow (“seeds”)

Tumor surgery process

Tumor sample sent to lab mid-surgery to check cell abnormality → determines how aggressively to remove it.

Primary CNS Tumor

Originates in the brain (90%)

Metastatic Tumor - Spread from…? Common sources? Usually causes…?

• Spread from another part of the body (10%).

  • Common sources: Lung cancer, melanoma.

Usually causes multiple brain tumors.

Why Brain Tumors Occur (Even Though Neurons Don’t Divide)-Most brain tumors come…? Glial cells…?

• Most brain tumors come from glial cells, not neurons.

• Glial cells (astrocytes, oligodendrocytes, Schwann cells) do divide → can become cancerous.

Why Brain Tumors Occur/Tumor Cell Type:

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1. Tumor Cell Type (What cell it comes from)

   • Tumors are named by the kind of cell they originate from—for example:

     • Gliomas (from glial cells)

     • Meningiomas (from meninges)

     • Astrocytomas (from astrocytes)

     • Oligodendrogliomas (from oligodendrocytes)

   • This helps determine how the tumor behaves and how it’s treated.