If the number of neurones changes little after birth, what does change as a child's brain develops?

The dendrites grow and branch, enormous numbers of synapses are formed between the existing neurones, and the axons become myelinated.

What is synaptogenesis?

Synaptogenesis is the formation of new synapses between neurones.

Why does the young brain form far more synapses than it will keep?

Overproducing connections and then keeping the ones that are used allows the wiring of the brain to be shaped by the child's actual experience rather than fixed in advance.

What is synaptic pruning?

Synaptic pruning is the loss of synapses that are seldom used, leaving the frequently used pathways in place.

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Biological Molecules

Topic overview Inorganic ions and the properties of water Monosaccharides and disaccharides Polysaccharides, storage and structure Lipids, triglycerides and phospholipids Amino acids and protein structure Condensation, hydrolysis and the food tests

Cell Structure and Organisation

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Neurobiology and Behaviour: The BrainNeurobiology

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Neurobiology and Behaviour: NeuroscienceNeurobiology

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Neurobiology and Behaviour: Neuroscience

Brain development and critical periods

3 things to know
Component 3

Overview

Synaptic pruning and critical period.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

Why does myelination matter to a child's development?

Key term

Distinguish a critical period from a sensitive period.

Key term

When are most of the neurones of the human brain produced?

Questions from this subtopic

Each one with the model answer underneath.

1
When are most of the neurones of the human brain produced?
Model answer
Almost all of them are produced before birth, during the development of the embryo and fetus.
2
If the number of neurones changes little after birth, what does change as a child's brain develops?
Model answer
The dendrites grow and branch, enormous numbers of synapses are formed between the existing neurones, and the axons become myelinated.
3
What is synaptogenesis?
Model answer
Synaptogenesis is the formation of new synapses between neurones.
4
Why does the young brain form far more synapses than it will keep?
Model answer
Overproducing connections and then keeping the ones that are used allows the wiring of the brain to be shaped by the child's actual experience rather than fixed in advance.
5
What is synaptic pruning?
Model answer
Synaptic pruning is the loss of synapses that are seldom used, leaving the frequently used pathways in place.
6
Why does myelination matter to a child's development?
Model answer
Myelin greatly increases the speed at which impulses travel, so abilities improve as the tracts serving them become myelinated, and the regions concerned with planning and judgement are the last to finish.

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