Brain Development
● Brain is composed of 3 main areas
● Starts at 3 weeks embryo
● The brain grows from a single layer ectoderm into neuroepithelia
● Neuroepithelial: pseudostratified; cell split 🡪 neuroblast and cell progenitor Forebrain (prosencephalon):
diencephalon (integration to tele, regulation mind and sleep, glands), telencephalon (top, vast majority
and most expandable (finish by the age of 20 ish), cerebrum or cortex)
,● Neuroblasts cannot divide anymore (postmitotic cell): after migration phase it will develop into a neuron
● Shh ventral floorplate
● By 14th week cortex is on top, started to get divided
● 5th month: nerve cell generation is nearly complete, myelination Is already visible
● 9th month: real gyri and sulci is already formed (cortex)
● Hemispheres of telencephalon are held together by corpus callosum and within them, by the internal
capsule.
, 1. Mitosis
● Once neuroblasts are formed from mitosis of neuroepithelia, they will become fixed
● Firstly, only neuroblasts are made, then at the switch point, they turn to asymmetric division and start also
to make glia cells
● Radial glia: spider web structure, to pial surface
● The body of the radial glial cells it at the ventricular zone, projections are more to the pial surface (cortex)
2. Migration
● Axon (microtubules), neurons have growth cones, made of actin bundles (so they can move, contracting,
the rest of the neuron by “holding” the axon)
● How neurons know where to go?
1. Chemical signals
2. Proteins to detect signals
Growth probes scan their environment to then make a contact if they will
3. Differentiation
● Neurons only become fix when they are already divided and specialized
● Axons, dendrites and neurotransmitter (ex.: Gaba)
● Differentiate according to the cell fate
● Develop electric conduction: (how? What gene)
● Brain is composed of 3 main areas
● Starts at 3 weeks embryo
● The brain grows from a single layer ectoderm into neuroepithelia
● Neuroepithelial: pseudostratified; cell split 🡪 neuroblast and cell progenitor Forebrain (prosencephalon):
diencephalon (integration to tele, regulation mind and sleep, glands), telencephalon (top, vast majority
and most expandable (finish by the age of 20 ish), cerebrum or cortex)
,● Neuroblasts cannot divide anymore (postmitotic cell): after migration phase it will develop into a neuron
● Shh ventral floorplate
● By 14th week cortex is on top, started to get divided
● 5th month: nerve cell generation is nearly complete, myelination Is already visible
● 9th month: real gyri and sulci is already formed (cortex)
● Hemispheres of telencephalon are held together by corpus callosum and within them, by the internal
capsule.
, 1. Mitosis
● Once neuroblasts are formed from mitosis of neuroepithelia, they will become fixed
● Firstly, only neuroblasts are made, then at the switch point, they turn to asymmetric division and start also
to make glia cells
● Radial glia: spider web structure, to pial surface
● The body of the radial glial cells it at the ventricular zone, projections are more to the pial surface (cortex)
2. Migration
● Axon (microtubules), neurons have growth cones, made of actin bundles (so they can move, contracting,
the rest of the neuron by “holding” the axon)
● How neurons know where to go?
1. Chemical signals
2. Proteins to detect signals
Growth probes scan their environment to then make a contact if they will
3. Differentiation
● Neurons only become fix when they are already divided and specialized
● Axons, dendrites and neurotransmitter (ex.: Gaba)
● Differentiate according to the cell fate
● Develop electric conduction: (how? What gene)
