8- Neuronal/Microscopic Development Flashcards
What are the 6 stages of neuron development?
Proliferation, migration, differentiation, synaptogenesis, myelination, arborisation
Which stage involves cell division and differentiation?
Proliferation
How many new cells are generated per minute in proliferation?
250,000
What allows stem cells to begin to differentiate?
Specialisation
What is specialisation guided by?
Chemical signals that trigger specific genes
What does it mean when stem cells are omnipotent?
They are able to develop to any tissue in the body
When can stem cells turn into neuroblasts?
Once they get chemical signals
What can neuroblasts become once they divide?
Any kind of cells in the nervous system
What is the key event in migration?
Neurons move to different places or different layers of the brain
What are the eventual destinations in migration?
Different for each neuron
What determines neurons’ final positions?
Genetic code
What guides the journey of neurons in migration?
Surrounding chemical signals
What is the chemical gradient like in migration?
Neurons move towards the direction where the chemical has a higher concentration
What do cells look like when they are migrating?
They have no dendrites and the axons are like tails without branches
When do cells align with specific neurons?
Once arriving to begin differentiation
How many layers is the human neocortex organised into?
6
What layer does migration begin with?
Layer 6
What can problems with cell migration lead to?
Developmental problems
What is an example when there is a problem with cell migration?
Dyslexia
What morphological changes happen in differentiation?
Changes to make them look like their neighbour neurons
What is the 1st step of differentiation?
Axon growth
What do axons determine in differentiation?
Who to form synapses with
What are chemoattractants?
Molecules attracting the growth cone
What are chemorepellants?
Molecules repelling the growth cone
What do neurons start to do in synaptogenesis?
Start to form axons and dendrites
When is a complex network of synapses created?
In synaptogenesis
What is the nerve growth factor?
A protein or nutrient that promotes neural growth
What happens if a cell doesn’t receive the nerve growth factor?
Apoptosis
Why do working synapses attract nerve growth factor?
To provide more nutrients
How many neurons and synapses do newborns have?
Lots of neurons but few synapses
When does synapse formation increase and peak?
Increases after birth and peaks in childhood
What is the role of neuronal pruning?
To remove unnecessary synaptic connections
How is the strength of a synapse determined?
By how it’s being used
What does the Hebbian Theory of how neurons are wired say?
‘Neurons which fire together wire together’ and ‘neurons which fire out of synch lose their link’
Which stage only happens in axons?
Myelination
What happens in myelination?
Layer of fatty tissue starts to emerge covering a neuron’s axon
What type of cells surround the axon of a neuron?
Glial cells
What makes transmission of an action potential more efficient?
Myelination
When is there further growth of dendrites?
Arborisation
What happens in arborisation?
Dendrites grow to smaller dendrites and create connections
What did Gaser and Schlaug find?
Bigger volume in brain regions related to playing and perceiving piano found in musicians
What did Draganski et al do?
Trained volunteers to juggle
What did Draganski et al find?
An increase in volume of motor cortex
