🔑 Key Definitions
Nature vs. Nurture: Debate over whether neural development and function are primarily determined by genetics or environmental experience
Neural Plasticity: The brain's ability to reorganize and form new connections in response to experience
Adult Neurogenesis: The formation of new neurons in the adult brain, particularly in hippocampus and olfactory bulb
Stem Cells: Undifferentiated cells capable of developing into various specialized cell types including neurons
Neural Plasticity: The brain's ability to reorganize and form new connections in response to experience
Adult Neurogenesis: The formation of new neurons in the adult brain, particularly in hippocampus and olfactory bulb
Stem Cells: Undifferentiated cells capable of developing into various specialized cell types including neurons
👤 Important Figures
- David Hubel & Torsten Wiesel - Nobel Prize winners; demonstrated critical periods through kitten eye occlusion and whisker experiments
- Mriganka Sur - Showed brain plasticity by rewiring ferret visual input to auditory cortex
- Viktor Hamburger - Conducted classic chick limb removal experiments demonstrating trophic factor dependence
🧠 Key Experiments & Findings
- Hubel & Wiesel Kitten Studies: Suturing one eye closed during critical period caused permanent visual deficits; demonstrated experience-dependent development
- Whisker Barrel Experiments: Removing whiskers altered cortical barrel organization, showing sensory input shapes brain structure
- Violin Players' Brains: Enlarged cortical representation of left-hand fingers demonstrates use-dependent plasticity
- Sur's Rewiring Experiments: Visual input rerouted to auditory cortex resulted in visual processing in "auditory" areas
- Hamburger's Chick Experiments: Removing limb bud reduced motor neurons, adding extra limb increased neurons
📊 Adult Neurogenesis Evidence
- Birds: Seasonal neurogenesis in song control nuclei related to learning new songs
- Rats: New neurons continuously generated in dentate gyrus (hippocampus) and olfactory bulb
- Primates: Adult neurogenesis confirmed in hippocampus; potential for therapeutic applications
💡 Exam Tips
- Hubel & Wiesel proved experience matters - connect to critical periods
- Remember Sur's rewiring shows brain can adapt function to input, not just structure
- Adult neurogenesis challenges old dogma that "you can't grow new neurons"
- Nature vs. nurture is not either/or - both genes AND experience shape the brain
- Violin player example shows practice physically changes brain structure
- Hamburger's experiments demonstrated target-derived trophic support