PSYCHOBIOLOGY: brain development Flashcards
describe how neurons are produced
- neural tube develops into CNS
- CNS divisions appear
- form ventricles and surrounding brain structures
what is the precursor structure?
- neural plate
- neural groove
- neural tube
where do neurons and glia develop?
neural stem cells at ventricular surface
step 1 of neuron development
cell proliferation
describe cell proliferation
division
- undifferentiated stem cell grows extension
- cell nucleus moves up and duplicates DNA
- nucleus moves down
- cell retracts extension and divides in 2
- if split is vertical, both daughter cells repeat the process
- if split is horizontal, one daughter cell repeats
when does cell proliferation stop
weeks after birth
stage 2 of neuron development
cell migration
rostral location
front end
caudal location
tail end
dorsal location
back
ventral location
belly
origin and migration of pyramidal cells & astrocytes
- dorsal areas
- vertically
origin and migration of interneurons and oligodendroglia
- ventral areas
- laterally
describe the process of cell migration
- radial glia cells in ventricular zone extend thin processes towards surface
- developing neurons crawl along the processes
- cells take up residence in subplot layer
- cells migrate to cortical plate from inside out
- interneurons move in sideways
stage 3 of neuron development
forming pathways
3 stages of forming pathways
direction
finding target structure
finding target cell
describe the process of forming pathways
- hemispheres receive signals, send commands to contralateral side
- growing axons guided by chemical signals which are modified by environment
- axons attracted to chemicals from specific target structure (chemo affinity hypothesis)
- sensory and motor cortices form maps
what does wiring of the nervous system depend on?
dynamic, coordinated electrical activity
describe the process of overabundance and pruning
- axons synapse with cells in target structure (initially too many synapses)
- supported synapses are strengthened
- neurons which lose too many connections die
describe correlational activity in neurons
when both pre and postsynaptic neurons are active, strengthens connections
