Flashcards in Development of the Nervous System Deck (31):
Name 3 molecules that inhibit BMP.
Chordin, Noggin, Follistatin
What does mesoderm inhibit to induce nervous differentiation in the ectoderm?
In what direction does the neural tube close?
Cranial to caudal
Name the 5 secondary vesicles and the primary vesicles from which they come.
Telencephalon & diencephalon from forebrain. Mesencephalon from midbrain. Metencephalon and myelencephalon from hindbrain.
Which secondary vesicle do the olfactory lobes, hippocampus, and cerebrum come from?
Which secondary vesicle do the retina, epithalamus, thalamus, and epithalamus come from?
Which secondary vesicle does the midbrain come from?
Which secondary vesicle does the cerebellum and pons come from?
Which secondary vesicle does the medulla come from?
What gene can you knock out to cause anencephaly in mice? (specifically, no formation of all anterior neural structures)
What transcription factors repress each other in the telencephalon (forebrain)? Which one is expressed anteriorly? What promotes its expression
Pax6 and Emx2. Pax6 is expressed anteriorly and is promoted by FGF8.
What division of the brain has rhombomeres during development?
What's the significance of the order of Hox genes on the chromosome?
Order on the chromosome recapitulates cranial-caudal sequence of gene expression.
Which two factors are most important in determining the dorsal-ventral axis of the neural tube? Which does which?
Shh (ventrally from the notochord) and BMP (dorsally from ectoderm).
What is holoprosencephaly? What's one way is happens?
Defect of bifurcation of forebrain into two lobes -> single holosphere. Can happen due to loss of Shh signaling components.
Describe the intrinsic lineage mechanism for differentiation.
Factors within the progenitor cell are unevenly divided among the cell's progeny, and these factors determine the progeny's fate. (the "European" way - less social mobility.....)
Describe the extrinsic mechanism for cell differentiation.
Extrinsic factors act on the progeny of a progenitor cell to determine its fate. (the "American" way -more social mobility.... but not actually)
What do the majority of neural crest cells below the neck do? Name 4 specific things.
Peripheral nervous system: Sensory ganglia, autonomic ganglia, and adrenal neuro-secretory ganglia. Also non-neuronal melanocytes.
Do neural crest cells differentiated by an intrinsic or extrinsic mechanism?
Extrinsic, due to local signaling molecules, as is illustrated by chick-quail transplant studies.
What's an experiment that showed puripotency of progenitor cells in the CN (specifically in the retina).
Progenitor cell injected with virus. Cells of various types that had come from the same clone could be identified based on the presence of the virus.
Where is the proliferative zone in the cortex for excitatory neurons? (ie. which side are the progenitors on, ventricular or pial?)
Ventricular. Excitatory neurons have "inside-out" development.
Where are inhibitory GABAnergic neurons in the cortex generated? What happens if these fail to develop?
The ventral telencephalon. Without them, people lack inhibitory interneurons and get epilepsy.
What is lissencephaly? What gene defect can cause it?
Smooth brain - lack of gyri and sulci. Loss of Lis1 can cause lissencephaly.
What does Doublecortin (dcx) do?
It's a microtubule-associated protein (MAP) needed for neuron migration
What is the growth cone?
The motile structure at the tip of the neuron.
What are 3 types of signals that can guide axon migration?
Chemorepulsion, chemoattraction, and contact attraction.
What axon-guidance factor directs the crossing of interneuron axons, given as an example in lecture (for fish tickling, and human eye coordination)
What do Sperry's frog experiments on eyes tell you about axon regeneration?
Retinal fibers regenerated to their original positions in the tectum, not to what's closest, frustrating their efforts to catch flies.
What axon attractants/repellents set up the anterior-posterior axis in the optic tectum? Which ones set up the dorsal-ventral axis?
A-P: Ephrin As (mnemonic: A is for Anterior-posterior)
D-V: Ephrin Bs
More neurons are born than become functional. What's a family of signaling molecule that promotes the survival of specific neurons?