Lecture 6: Developmental Genetics of Human Brain Flashcards
What can defects in brain develop lead to?
- Epilepsy
- Learning/Intellectual disabilities
- Autism Spectrum Disorder
- Brain Cancer
What is the oldest way of looking at the brain?
Pathology
What is most used to view the brain now?
MRI
Why is pathology through MRI not as useful as genetics?
Genetics is useful to understand what causes normal and abnormal development
What does Karyotype, CGH, and Next-generation Sequencing looking at?
- Karyotype - full chromosome
- CGH - Section of DNA missing
- Next-generation Sequencing - Single Base Pair
What is the Telencephalon?
Another name for the Cortex or the outer part of the brain
What is the Rhombencephalon?
The Brainstem
What are the three parts of the Brainstem?
- Medulla oblongata
- Pons
- Diencephalon
What is Gastrulation?
The formation of 3 layers of cells
What are the three layers of cells?
- Endoderm
- Mesoderm
- Ectoderm (neuron, skin)
What does the Ectoderm end up forming?
Neurons and skin
What is Neuralation?
The formation of the neural tube from a flat layer of ectodermal cells
Which layer of cells undergoes Neurulation?
The ectodermal cells
What is the Sonic Hedgehog Gene?
A gene that is expressed in many steps of brain development
Which cells begin to express the SHH?
The notochord
What does the notochord expressing sonic the hedgehog do?
Causes expression of the SHH in the floor plate
What genes are secreted from the ectoderm?
BMP
Which genes are expressed dorsally and ventrally in Neuralation?
TGF and BMP are expressed dorsally. SHH is expressed ventrally
Which part of the neural tube closes first?
The Anterior pore followed by the posterior pore
What causes Anencephaly?
Defect of the anterior neuropore closure
What causes Spinabifiida?
Failure of closure of the posterior pore
Which pore not closing will patients survive?
Failure of closure of the posterior pore
What does the anterior part of the neural tube do?
Splits into two prosencephalic vesicles
What occurs during Prosencephalic development?
The splitting of the neural tube
What is Holoprosencephaly?
The failure of cleavage of the two hemispheres
Which gene is involved in the Holoprosencephaly?
The sonic the hedgehog gene
What is Mobius Syndrome?
Congenital partial or complete facial diplegia
What is the cause of möbius syndrome?
Hoxb-1 and Hoxb-4 genes
What occurs in Neuronal Proliferation?
Making the hemispheres bigger
What is hemi-megalencephaly?
A hemisphere is bigger than another one
How many layers in the human cortex?
Six
What occurs in neuronal migration?
The neurons are born in the center periventricular zone and migrates out of progenitor glial cells
What is Periventricular Nodular Heteropia?
When neurons don’t migrate outward properly
What is the functions of the bumps on the brain?
Allows the brain to pack more tissue
