Q&A Hero

Q: Roger Sperry cut a newt's optic nerve and rotated the eye. Axons from what used to be the dorsal part of the retina (now located on the ventral side) grew back to the target areas: a. that ordinarily get input from the dorsal retina. b. that ordinarily get input from the ventral retina. c. that ordinarily get input from the center of the retina. d. equally and diffusely.

Q: Chemicals in the amphibian tectum guide the growth of axons from the retina to their correct location in the tectum by: a. having dozens of different growth factors. b. using an electrical gradient. c. using a chemical gradient. d. glial cell transportation.

Q: If you cut the optic nerve of a newt, what happens? a. The fibers grow back and attach to random targets, so they see a scrambled picture. b. The fibers grow back and attach to their original targets, resulting in normal vision. c. The newt remains blind, since neurons do not regenerate. d. The fibers attach to multiple targets, resulting in blurry vision.

Q: What process occurs when axons attempt to form connections to a grafted limb in a salamander? a. Axons connect randomly, but only muscles "tuned" to the right message respond. b. Axons connect randomly and muscles learn to coordinate through experience. c. Axons find their way to corresponding muscles in the new leg. d. A lack of nerve growth fiber leads to the degeneration of the new leg.

Q: What happened when Weiss grafted an extra leg onto a salamander adjacent to one of the hindlegs? a. The new leg gradually took over for the old. b. The new leg withered and died. c. Nerves from the old leg attached to the new in a random fashion. d. Branches of axons from the old leg attached to corresponding muscles in the new.

Q: Brain cells that are neither neurons nor glia, but which are capable of dividing and then differentiating into neurons or glia, are called: a. parallel fibers. b. intrinsic cells. c. stem cells. d. glomeruli.

Q: As a rule, all vertebrate neurons develop during an embryological stage. Among the few types of neurons that can develop in adulthood are: a. ganglion cells in the retina. b. olfactory receptors. c. motor nerves in the spinal cord. d. long-axoned neurons of the primary motor cortex.

Q: New neurons are known to develop in all of the following cases EXCEPT: a. olfactory receptors. b. the human corpus callosum. c. the brain area responsible for birdsong. d. hippocampus of mammals.

Q: The formation of new synapses is called: a. synaptogenesis. b. differentiation. c. migration. d. fusion.

Q: The final stage of neurodevelopment is called: a. synaptogenesis. b. differentiation. c. migration. d. fusion.

Q: The stages of neurogenesis that occur for the longest duration are: a. myelination and synaptogenesis. b. proliferation and myelination. c. migration and proliferation. d. differentiation and migration.

Q: Myelination in the human brain: a. is complete upon birth. b. is complete around the second birthday. c. is complete sometime shortly after adolescence. d. continues well into the adult years.

Q: In humans, myelination first occurs in the: a. spinal cord. b. hindbrain. c. midbrain. d. forebrain.

Q: For some axons, glial cells produce an insulating sheath that makes rapid transmission possible. What is this process called? a. Differentiation b. Migration c. Myelination d. Proliferation

Q: Myelination is a process common to: a. all vertebrate axons. b. all vertebrate dendrites. c. some vertebrate axons. d. some invertebrate axons.

Q: After the migrating neuron reaches its destination, ____ begin to form. a. dendrites b. axons c. nuclei d. ganglions

Q: Whether or not a transplanted immature neuron adopts the properties of neurons in the new location or retains at least some properties of neurons from where it was taken from depends largely on how much the transplanted neuron has: a. myelinated. b. proliferated. c. migrated. d. differentiated.

Q: The formation of a neuron's distinctive shape occurs during the ____ stage of neurogenesis. a. proliferation b. migration c. differentiation d. myelination

Q: What is the process called when a primitive neuron begins to develop dendrites and an axon? a. Differentiation b. Migration c. Myelination d. Proliferation

Q: Differentiation is the: a. production of new cells. b. movement of primitive neurons and glia. c. formation of dendrites and an axon. d. insulation process that occurs on some axons.

Q: Migration requires: a. a precise chemical environment. b. cells which are myelinated. c. mature neurons. d. neurons with fully developed dendrites.

Q: Which of the following best characterizes how axons arrive at the correct target cells? a. They follow electrical gradients. b. They follow chemical gradients from the target cell. c. Axons send out chemicals to the target cells. d. Target cells send out branches for the axons to follow.

Q: Immunoglobulins and chemokines play an important role in neural: a. migration. b. proliferation. c. synaptogenesis. d. apoptosis.

Q: Migration is the: a. production of new cells. b. movement of primitive neurons and glia. c. gradual formation of dendrites and an axon. d. insulation process that occurs on some axons.

Q: Which of the following would most likely interfere with migration of neurons during development? a. altering the chemical paths b. damaging dendrites c. loss of myelin d. increased differentiation

Q: What term describes the movement of primitive neurons and glia within the developing nervous system? a. Differentiation b. Migration c. Myelination d. Proliferation

Q: Chemicals known as ____ and ____ guide neuron migration. a. immunoglobulins; sodium b. glia; neurothrophins c. immunoglobulins; chemokines d. chemokines; neurothrophins

Q: After cells have differentiated as neurons or glia, they: a. differentiate. b. proliferate. c. myelinate. d. migrate.

Q: Proliferation occurs: a. at the top of the spinal column. b. around the vesicles. c. around the ventricles. d. at the expanding edge of the brain.

Q: Proliferation is the: a. production of new cells. b. movement of primitive neurons and glia. c. formation of dendrites and an axon. d. insulation process that occurs on some axons.

Q: Stem cells are important for which of the following developmental processes? a. migration b. proliferation c. myelination d. synaptogenesis

Q: What is the production of new neurons called? a. differentiation b. migration c. myelination d. proliferation

Q: The fluid-filled cavity of the developing neural tube becomes the: a. forebrain. b. midbrain. c. spinal cord. d. ventricular system.

Q: When do the ventricles and the central canal of the spinal cord form? a. shortly after birth in humans b. just as the forebrain starts its rapid phase of growth c. early in embryonic development d. during the third trimester

Q: As the neural tube sinks under the surface of the skin, the forward end enlarges and differentiates into the: a. spine, midbrain, and forebrain. b. hindbrain, midbrain, and forebrain. c. hindbrain, midbrain. d. midbrain, forebrain.

Q: The human central nervous system: a. begins to form during the fetal stage. b. is unlike all other vertebrate central nervous systems in its developmental process. c. begins to form when the embryo is about two weeks old. d. begins to form when the embryo is about two months old.

Q: Early in development, the nervous system begins as a: a. tube surrounding a fluid-filled cavity. b. spherical structure in the center of the embryo. c. diffuse system of cells scattered throughout the body. d. single layer of cells covering the heart and other internal organs.

Q: The ability of the brain to change its anatomy over time, within limits, is known as: a. plasticity. b. regression. c. connectivity. d. long term potentiation.

Q: Deafferentation of the left arm results in the inability to move it.

Q: Recent evidence suggests that phantom limb pain is caused by sensations coming from the stump of the amputated limb.

Q: Denervation supersensitivity results from the disuse of incoming axons.

Q: Paralysis caused by spinal cord injury is usually only temporary in humans.

Q: An axon in the peripheral nervous system is more likely to recover after being cut than if it is crushed.

Q: One effective method to overcome diaschisis after brain damage is to administer stimulant drugs.

Q: Diaschisis refers to the decreased activity of surviving neurons after damage to other neurons.

Q: The damaging effects of a stroke can be limited if treated within a short period of time.

Q: In strokes caused by ischemia or hemorrhage, neurons die from overstimulation.

Q: The most common cause of brain damage in children is closed head injury.

Q: A rat in a more stimulating environment develops a thicker cortex, more dendritic branching, and improved learning.

Q: Exercise may account for some of the neural benefits that come from rearing rats in an enriched environment.

Q: Physical exercise is important for increased dendrite growth and branching.

Q: The developing infant brain is highly resistant to damage.

Q: Nerve growth factor is a chemical that promotes the survival and activity of neurons.

Q: Apoptosis is distinct from necrosis, which is death caused by an injury or a toxic substance.

Q: The brain requires millions of chemicals to correctly guide the growth of axons to their target locations.

Q: Mammals and amphibians are similar in that they can both easily generate new axons.

Q: The number of neurons in the brain is continually increasing throughout life.

Q: Recent evidence suggests that adult vertebrate brains generate new neurons.

Q: Synaptogenesis is a process that begins before birth and continues throughout life.

Q: Myelination of the brain and spinal cord is complete by the time of birth.

Q: Some neurons provide the myelination for other neurons.

Q: An early and fast stage of neuronal development is myelination.

Q: After cells have differentiated as neurons or glia, they migrate.

Q: Axons are usually formed before the dendrites.

Q: Proliferation is the production of new cells.

Q: The fluid-filled cavity within the neural tube becomes the central canal of the spinal cord and the four ventricles of the brain.

Q: Once the brain is fully developed, the anatomy of the brain is unchanging.

Q: The human central nervous system begins to form when the embryo is about 10 weeks old.

Q: Describe the relationship of sensory representation and phantom limb sensation.

Q: Briefly describe sprouting.

Q: Briefly describe how strokes affect the brain.

Q: Describe how experience can alter brain development (give a specific example).

Q: Describe the five main stages of growth and development of neurons.

Q: Describe how phantom limb sensations that seemingly come from a missing hand might occur when the face is touched.

Q: Define denervation supersensitivity.

Q: Describe how axons reach their targets during development.

Q: Define myelination during neural development.

Q: Define differentiation during neural development.

Q: Define proliferation during neural development.

Q: In general, what can we say about recovery for brain-damaged patients in the future?a. There is very little hope of recovery.b. Researchers are optimistic, but they need to evaluate many possible therapies.c. Drug therapies have clear advantages over all other approaches.d. Brain grafts are the only real answer.