UNIT 1 - TOPIC 2

What happens during infancy and adolescence?

They are both critical periods of rapid brain development.

What brain processes are important in infancy and adolescence?

1. Myelination

2. Synaptic pruning

3. Development of the forebrain

What is developmental plasticity?

The formation of synapses between infancy and the end of adolescence

What processes happen during developmental plasticity?

1. Synaptic pruning

2. Myelination

These process happen at the same time

What does the brain during infancy suggest?

That the brain is highly adaptable and forms many new neural connections.

What is synaptic pruning?

It involves the elimination of excess neurons and synapses; that is, those that have not established a connection with a neighbouring cell will die.

Why is synaptic pruning important?

It makes the brain more efficient by preserving only the most useful connections.

What is myelination?

It is the process where the axons of the neurons in a child's brain become insulated by myelin, which speeds up neural transmission.

When does myelination begin and end?

It occurs before a baby is born and does not finish until about 23 years of age.

In infancy, how does myelination progress?

It progresses from lower brain structures (cerebellum, medulla, pons etc.) upward to the cerebral hemispheres (occipital, temporal and parietal, then frontal).

What happens to the brain during adolescence?

Synaptic pruning and myelination continue as the brain undergoes another wave of major changes.

What happens in synaptic pruning during adolescence?

There is "a second wave of pruning in early adolescence," where the brain again eliminates unused connections to increase efficiency.

What happens in myelination during adolescence?

It continues, especially in the frontal lobes, which are responsible for higher-order thinking like planning and impulse control.

What is the last part of the frontal lobe to develop?

Prefrontal cortex (into the mid 20s)

What happens during puberty?

Significant changes in specific brain regions occur

What brain regions are changed in adolescence?

1. Amygdala

2. Cerebellum

3. Corpus Callosum

How does the amygdala change in adolescence?

It becomes more active and is linked to emotions

How does the cerebellum change in adolescence?

It helps with motor control

How does the corpus callosum change in adolescence?

It thickens and increases communication between the two hemispheres

What do changes in specific brain regions do to adolescents?

It helps to regulate thinking, behaviour and emotions.

What is neural plasticity?

It is the brain’s ability to change its structure and function in response to environmental stimuli.

Why is neural plasticity important?

It allows for learning and adaptation throughout life.

When is neural plasticity most active?

In infancy, childhood and adolescence, when neural pathways are still developing and consolidating.

What periods shape plasticity?

1. Critical period

2. Sensitive period

What is a critical period?

A period in development when certain experiences must happen for typical development to proceed.

What is a sensitive period?

A more flexible, optimal time for an individual to learn new things due to the nature of the growing brain.

Example of a critical period

Babies must be exposed to light shortly after birth to properly develop vision.

What happens if a neural connection is not formed during a critical period?

It will struggle to form, or may never form.

What happens if a neural connection is not formed during a sensitive period?

Learning is still possible later, but it will be more difficult to achieve.

What environmental conditions shape plasticity?

1. Enriched environment

2. Deprived environment

What is an enriched environment and how does it shape plasticity?

It involves stimuli from social and physical surroundings. It helps neural pathways to develop and consolidate effectively.

What is a deprived environment and how does it shape plasticity?

It lacks stimuli, leading to impaired development.

Two examples of deprived environment

1. Genie Wiley, raised in isolation and deprived of language, never learned to form grammatical sentences after missing the sensitive period for language.

2. Rosenzweig, Bennet, and Diamond's (1972) rat study. Rats raised in enriched environments developed “increased neuron activity in the cerebral cortex” compared to deprived rats

What can neural plasticity recover?

Brain damage - recovery of this is called adaptive plasticity

What is adaptive plasticity?

It is where the brain reorganises itself to compensate for lost functions or form new connections. Although more limited than during developmental plasticity, it still allows people to relearn or adapt after injury.