psychological psychology
NA19811981
11.growth.pptGrowth & Development of Brain
Discussion Question…
- Lynn is a newborn infant. What are some of the things which will be necessary for her to grow into a functioning, adult member of society?
How do neurons get to their proper location?
How do they get connected?
Proliferation, Migration, Axon Growth, Differentiation,
Myelination, Synaptogenesis
Proliferation of nerve cells
- Stem cells neurons, glia
- Occurs near the ventricles
- 250,000 new cells per minute
Migration of Neurons
- During prenatal development (8-15 weeks)
- Example: retina of eye starts as part of cortex
- http:// www.youtube.com/watch?v=ZRF-gKZHINk
Axon Growth
- Axons grow as the neuron soma migrates
- Axon growth cone follows chemical signals
- Chemokines, immunoglobins
- http://www.youtube.com/watch?v=62HPVy9myK8
Differentiation— developing the necessary neuron structure
- Dendrites gradually form after migration
http://www.youtube.com/watch?v=EP4yeyD8ktY
- Greater flexibility earlier in life
Purkinje Cell (cerebellum) Bipolar Cell (eye)
Myelination
Glial cells myelinate the axons
Long-term process, begins in spinal cord
Synaptogenesis
- Formation of synapses:
- Neuron-neuron
- Neuron-muscle
- Neuron-gland
- Overabundance of neurons & synapses
- “Use it or lose it”
- Apoptosis— unused neurons commit suicide
- http://www.youtube.com/watch?v=gYWUTBM8tTo&feature=related
- http://www.youtube.com/watch?v=Z8gqSDfBlPY&feature=PlayList&p=20AA7FDD06BF4608&index=38
Neurotrophins
- Promote survival, prevent apoptosis
- Neurotransmitters & Neurotrophins released simultaneously
- What causes release of neurotrophins?
- Experience (stimulation)
- Enriched environment
- Exercise
- Education?
Teratogens -- Disruptions to brain development
- Alcohol/drug use
- Anesthesia
- Malnutrition
- Smoking
- Infection
- Radiation
