Behav Neuro: Chapter 7 Brain Development

Exam 2 active recall

Development is shaped by two factors:

1. Intrinsic (genetic) 2. Extrinsic (environmental)

Ectoderm:

the outer layer that forms during gastrulation that becomes the NS.

Mesoderm:

muscle, heart, red blood cells

Endoderm:

lungs, endocrine glands, pancreas

Transcription Factors (TF)

Proteins that bind to DNA and broadly activate gene expression

Body Plan Segmentation

The body plan is set up from the earliest stage of embryonic development, and the genes that regulate this are highly conserved across all vertebrates.

Homeotic Proteins

TPs involved in body segmentation

When does the CNS form?

When embryo is 2 weeks old (during gastrulation)

How does the CNS form (stage 1)

The dorsal surface thickens, forming a neural tube surrounding a fluid filled cavity.

How does the CNS form (stage 2)

The anterior end enlarges and differentiates into the hindbrain, midbrain and forebrain. 

How does the CNS form (stage 3)

The rest of the neural tube becomes spinal chord. 

Neurogenesis:

1st stage in neural development; cells on inner side of neural tube undergo cell division in the ventricular zone (VZ)

Cells in the VZ provide the source from which all…

neurons and glial cells are derived. 

A combination of ___ and ____ decide what type of cell is made.

genetic and extracellular signals

Birth Date:

the point at which adult neurons stop undergoing cell division

Vertebrates are born with…

nearly all of the neurons they will ever have.

Increase in brain size is due to:

cell growth, increased branching, glial cell production and myelination. 

Neurogenesis occurs in adulthood in what 2 brain regions?

1. Olfactory bulb

2. Granule neurons in the dentate gyrus

Cell Migration:

The 2nd stage in cell migration. The movement of newly formed neurons and glia to their eventual location.

There are 2 types of cell migration. The first being:

Radial Migration —> occurs on scaffolding cells (radial glia) from the VZ toward the outer (pial) surface.

The second type of cell migration is:

Tangential Migration —> involves the movement of cells in the rostral-caudal axis of the CNS.

In the primate brain..

all neural cell migration is completed by birth.

Cell Differentiation:

3rd stage of neurogenesis. Process of cells adopting their phenotype appropriate for the particular brain region.

Neural Cell Adhesion Molecules (NCAMS)

are a class of chemicals expressed on the extracellular surface that guide cells and growing axons to their specific targets.