Flashcards in Module 5.1 Deck (26)
What are stem cells and where are they found?
Stem cells are undifferentiated cells that can divide and produce daughter cells that develop more specialized properties. They can be found in tissues in the body.
What are the five stages in the development of neurons? Describe the processes in each.
Proliferation: production of new cells
Migration: cells are born in ventricles and must move to eventual locations using chemical guides
Differentiation: form axons and dendrites
Myelination: myelin formed by glia
Describe the formation of the central nervous system in the embryo.
The central nervous system develops in utero starting with the neural tube which eventually become the brain and spinal cord.
Discuss the evidence that no new neurons are formed in the central cortex of humans.
The C-14 level in the DNA of neurons in the cerebral cortex corresponds to the level during the year the person was born. This means that almost all of those neurons are as old as that person is.
What did Weiss observe in his experiments on salamanders extra limbs? What principle did he conclude directed the innervation of the extra limb? Is this principle still thought to be correct?
After the axons reached the muscles in the new limb, it moved in synchrony with the normal leg next to it. He concluded that the nerves attached to muscles at random and then sent a variety of messages, each one tuned to a different muscle. This is not thought to be correct anymore.
What did Sperry observe when he damaged the optic nerve of newts?
he optic nerve that was cut, grew back and connected with thetectum. When the new synapses were formed, the newt regained normal vision
What happened when Sperry rotated the newt's eye by 180 degrees? How did the newt see the world?
It grew back to its place of origin. The newt saw the world upside down and backward
What did Sperry conclude from his experiment with the newt eye?
axons regenerate to their original target
How do axons find their targets?
by following a chemical trail
What happens to axons that form active synapses? What happens to axons that do not form active synapses?
Axons that form synapses, survive. Axons that do not form active synapses die.
Who discovered nerve growth factor?
What happens if a neuron in the sympathetic nervous system does not receive enough nerve growth factor?
If a neuron does not receive enough nerve growth factor, the cell body dies.
What is another neurotrophin besides nerve growth factor?
Brain-derived neurotrophic factor
What are the effects of thyroid deficiency in adulthood? Compare these with the effects of thyroid deficiency in infancy/
Thyroid deficiency can produce lethargy in adults, but it can produce mental retardation in infants.
causes hyperactivity, impulsiveness, difficulty maintaining attenton, varying degrees of mental retardation, motor problems, heart defects, and facial abnomalities
fetal alcohol syndrome
What effects of fetal alcohol on synaptic activity may affect the neural deficits?
Alcohol suppresses the release of glutamate, the brain's main excitatory transmitter, therefore manny neurons receive less excitation and neurotrophins than normal and they undergo apoptosis.
What are the effects of prenatal cocaine exposure?
The effects of prenatal cocaine exposure are decreased language skills, decrease in IQ score, and impaired hearing.
What are the effects of cigarette smoking during pregnancy?
Cigarette smoking during pregnancy have an increased risk for attention deficit disorder, aggressive behavior, and impaired memory and intelligence.
What are the effects of stress during pregnancy?
Stress during pregnancy can cause children to have an increase in problems in their social and academic lives.
Describe the ferret experiment. What can we conclude from it?
Experimenters used a ferret and on one side of the brain, they damaged its superior colliculus and the occiptial cortex and the inferior colliculus. The optic nerve was unable to attach to its usual target, so it attached to the auditory area of the thalamus, which lacked its usual input. So, parts of the thalamus and cortex that usually receive input from the ears, now received input from only the eyes. We can conclude that the cortex will adapt and develop some characteristics of a visual cortex.
Describe the effects of environmental enrichment.
Environmental enrichment can produce a thicker cortex, more dendritic branching, and improved learning.
How might exercise contribute to the effects of enrichment?
Brain volume and activity declines less in people who are physically active
What happens to the occipital lobes of people who were born blind?
It is still active and touch information invades a blind person's occipital lobe.
Describe the effects of music training on the brain.
Some areas of the brain become larger and/ or thicker.
What area is larger in people who have extensive experience with string instruments?
A section of the postcentral gyrus in the right hemisphere is larger in people who have had extensive experience with stringed instruments.