Developmental neurobiology Flashcards
How do we understand neural circuits
We need to understand how the nerves and circuits are assembled in space and time
When does the building of nerves happen
In embryogenesis
What are progerartive cells
Cells that differentiate into the nerves
When can the early brain and spinal chord be seen
4-5 weeks post fertilisation
What are model organisms
Vertebrates other than humans in which we can analyse their generation and assembly
What can you see 5 weeks post fertilisation
Anterior and posterior axis and dorsal parts of the nervous system
What is cell differentiation
The process by which cells become different from each other and acquire specialised properties
What are the extrinsic factors
Signals
What are the intrinsic determinants
Transcription factors
What are loss of function studies
We get rid of each external factor one at a time and we ask is the outcome still the same
What do loss of function and gain of function studies tell us
What the function of a cell is
What is gain of function
If we add or replace factors and get the same outcome
What is neural induction
In early development when some ectodermal multipotent cells change fate and become neural stem like cells
What is the key transcriptional factor active downstream of the BMP signalling pathway
Phosphorylated SMAD157
What are the antagonists that mop of up the BMPS
Chordin, noggin, follistain and GSC
How can removing a factor generate a new transcriptional response
Happens when you remove an inhibitor of an inhibitor
What are the transcription factors that mark the neural stem cells called
sox2
What is gastrulation
Is the process which transforms the embryo from a one dimensional layer of cells into a multilayered embryo in which the adult body plan is recognisable
What is the process of neuralation linked to
Gastrulation
What does the transcriptional signiture tell us
What the cell is and at what stage its at
Whats the best way to characterise a cell
through their mRNA and protein signatures
Whats an induced pluripotent cell
A cell that you take from an adult and put in factors which make it a pluripotent identity
What do organiser cells differentiate into as the neural plate is being induced
Prechordal mesoderm and notocord
What do organiser cells transcribe and secrete
BMP antagonists
What do the prechordal mesoderm cells secrete as well as BMP antagonists
Wnt antagonists for example Dikkopf
What are posterior parts of the embryo exposed to
What are the anterior parts exposed to
What does this lead to
High levels of Wnts
Wnt antagonists
Creates a gradient
What does Otx2 mark
Marks cells at the anterior end, cells that are going to become the brain
What experiments have been done to test that promoting the brain is caused by Wnt antagonists?
Experiments on zebra fish embryos and mice
What is controlling HOX genes
Wnt signals
Where were HOX genes first identified
Drosophila
Why do we study the spinal cord
Its simple and long in comparison to the brain
What cell forms at the border of the surface epidermis
Neural plate border cells
What do neural plate border important for
Neural crest formation and peripheral system development
Roof plate formation and dorsal neural tube patterning
The closure of the neural tube
What do neural plate border cells give rise to
neural crest cells
What are roof plate cells important for
Patterning and regionalisation
Whats the first transcription factor that turns neural plate border cells on
MXS and its transcriptionally activated at the intermediate levels of MBP signalling
What other transcription factors are upregulated in the neural plate border cells
c-Myc: governs cell proliferation
id: giving cells
and snail: gene that makes cells go under eptithlial to mesenchymal cell transition
What do neural crest cells give rise to
Schwann cells, melanocytes, osteoblasts and neurons in the peripheral and enteric nervous system
What are the different cell tyoes generated determined by
The position of neural crest cells, time of gerneation and migritory pathways
Where are motor neurons always born
In the ventral part of the spinal cord
Morophogen definition
A secreted signal made by source cells
What are the two models for how a single molecule can convey positional information
The french flag model
Reaction diffusion model
Whats the generic signal transduction pathway
A signal binds to a receptor that activates a signal transduction pathway leading to rapid cellular responses
What must a morphogen be able to do
To assume at least two different fates
What does neurogenesis mean
The birth of a neurone
What are the 3 different cells proginitors give rise to
Neurons, glia and astrocytes
Do all proginitors become neurones?
No
Whats the movement prolifererating proginitors undergo?
Interkinetic migration
What can happen once a cell has become a radial glia cell
It can divide symmetrically or assymetrically
What transcription factors directly regulates the expression of delta genes
Acheate-scute proteins
What are the two classes of migration
Tangential and radial
What happens if migration goes wrong
You get a brain condition known as Lissencephaly
What is the cerebellum derived from
Roof plate and neural crest cells migrating out from the roof plate of the spinal cord
What hypothesis did Weis propose
The resonance theory
What hypothesis did Sperry propose
The chemo affinity theory
What did sperrys experiment involve
Cutting the optic nerve and removing the temproal retina allowing the nasal axons to grow back
Whats the cajal growth cone
The growing tip of the axon which cajal proposed sensed cues in the environment
What are the two types of actin in the peripheral region
Lamella and filopodia
What are the 4 factors of axon guidance
Contact attraction, contact repulsion, chemoattraction and chemorepulsion
