Chapter 5.1 - Development of the brain

5 Written Questions

1. Each axon regenerated to the area of the tectum where it had originally been presumably by following a chemical trail - helped by chemical gradients (page 127)
2. The protein that is delivered and that promotes survival and growth, when a neuron of the SNS forms a synapse onto a muscle (muscle does delivering) - an axon that doesn't receive NGF degenerates and its cell body dies
3. Cut optic nerve of frog and rotated 180 degrees
   Axons from what originally was dorsal retina (now ventral) grew back to area for dorsal - axons from what had once been ventral (now dorsal) grew back to original target - frog saw world upside down
4. Neuron forms its axon and dendrites
5. Skin - turn over rapidly (less than yr)
   Skeletal - 15 years
   Cerebral cortex - from birth (form no or few new neurons after birth)

5 Matching Questions

1. Neurotrophin
2. neural Darwinism
3. Human central nervous system (CNS)
4. Migration
5. Synaptogenesis

1. a A chemical that promotes survival and activity of neurons (i.e. NGF)
   Neurons that fail to receive NTs, fail to receive these things and so they die out
2. b 1. begins to form when the embryo is 2 weeks old.
   2. dorsal surface thickens and then long thin lips rise, curl, and merge, forming a neural tube that surrounds a fluid-filled cavity 3. tube sinks under skin surface, forward end enlarges and differentiates into hind mid and forebrain (rest becomes spinal cord)
   4. Fluid filled cavity becomes central canal of spinal cord and 4 ventricles of brain, containing CSF
3. c we start with more neurons and synapses than we keep. selection process occurs where we keep others and reject others. the most successful axons and combinations survice, while others fail
4. d Final stage where synapses form - starts before birth but throughout life neurons form new synapses and discard old ones
5. e After cells differentiate into neurons or glia they migrate or move, some faster than others, slowest don't reach their destination till adulthood

5 Multiple Choice Questions

1. Brain is constantly changing, within limits - it changes rapidly in early development and continues changing throughout life
   1. Growth of brain
   2. Rest of chapter
   3. Plasticity of brain
   4. Average human brain
2. Remain immature throughout life - periodically divide with one remaining immature and other differentiating
   1. Myelination
   2. Neurons in humans
   3. Stem cells in nose
   4. Sperry experiment
3. Fetal alcohol syndrome
   "Crack baby"
   Impaired thyroid production produces lethargy in adults but retardation in infants (page 131)
   1. Growth of brain
   2. Vulnerable developing brain
   3. Plasticity of brain
   4. Average human brain
4. Immunoglobulins and chemokines - defecit in these leads to impaired migration, decreased brain size, decreased axon growth, and mental retardation
   Also, extreme excesses of immuno has been linked to schizo
   1. Average human brain
   2. Migration
   3. Chemicals that guide migration
   4. Proliferation
5. olfactory receptors, neurons in hippocampus, and neurons in song-producing areas of some bird species
   1. Brain areas where new neurons form
   2. neural Darwinism
   3. Stem cells in nose
   4. Neurons in humans

5 True/False Questions

1. Apoptosis → Final stage where synapses form - starts before birth but throughout life neurons form new synapses and discard old ones

   True        False

2. Growth of brain → Changes when you are really young, but when you are older it doesn't (more about dendrites growing and making new connections) ---- Think about all the things a one year old can do that they couldn't at birth = brain growth ----Think about all the things you couldn't do a few years ago like analyze stats. etc.. = dendrites have grown new branches

   True        False

3. Effects of being active → Enhances growth of axons and dendrites, even for rats in isolation
   Improves learning and memory
   Neuronal changes in humans
   Being mentally active help fight the declining brain volume and activity characteristic of elderly people

   True        False

4. Myelination → After cells differentiate into neurons or glia they migrate or move, some faster than others, slowest don't reach their destination till adulthood

   True        False

5. Proliferation → After cells differentiate into neurons or glia they migrate or move, some faster than others, slowest don't reach their destination till adulthood

   True        False