PSY2061 Study Guide - Final Guide: Embryonic Stem Cell, Neural Plate, Neural Tube
11 Jun 2018
School
Department
Course
Professor
Nathaniel Parsons
PSY2061 Learning Objectives Week 1 S1 2018
Introduction to Development
Describe the pre and post-natal development of the brain:
There are 5 phases of neurodevelopment.
A zygote is a cell formed from the amalgamation of an ovum and a sperm. The zygote then
divides to form 2 daughter cells, 4 daughter cells, 8 daughter cells etc. These cells must
differentiate into their specific functions and make their way to specific sites. At these sites
the cells align to form structures by establishing functional connections.
This process is accomplished in 5 phases within the prenatal development stage.
1. Induction of the neural plate
2. Neural proliferation
3. Migration and aggregation
4. Axon growth and synapse formation
5. Neuron death and synapse rearrangement
Understand the development of the neural plate into the neural tube, and the term
stem cell:
The neural plate is a small patch of ectodermal tissue (outside layer) on the dorsal (behind)
surface of the developing embryo. The development of the neural plate is the first major
stage of neurodevelopment in vertebrates and is induced by chemical signals from an area
of the underlying mesoderm layer (middle layer/ organiser).
The cells of the neural plate are embryonic stem cells. There are 2 crucial functions of stem
cells: they can replicate themselves and they can differentiate into many types of cells
(totipotent, pluripotent or multipotent). When a stem cell divides, two daughter cells are
created – one replica stem cell and another that develops into a body cell. Stem cell culture
cannot last forever because after multiple replications errors begin to occur during
replication.
Describe the process of neural proliferation and identify the two organizer areas:
The neural groove fuses to form the neural tube and then the cells begin to proliferate. There
are two organisers in the neural tube – the floor plate and the roof plate. Cells of the tube
begin to proliferate (multiply) usually in the ventricular zone, the region adjacent to the
ventricle.
Describe the process of migration and aggregation:
Migration occurs once the cells are created in the ventricular zone of the neural tube. They
move to their appropriate target location specific to the cell. The cells are still immature as
they lack characteristics of mature neurons (eg. without axons and dendrites). There are two
factors which govern cell migration – time and location.
There are two forms of migration. Radial migration is when the cells proceed from the
ventricle zone in a straight line out of the neural tube. Tangential migration occurs at right
angles to radial migration, i.e. the cells travel parallel to the neural tube.
Cells use somal translocation which is an extension that grows from the developing cell to
help it move in the direction of migration. The extension uses environmental cues around the
cell to help guide it to its site. There is also glia-mediated migration which is where radial
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