Plasticity and functional recovery of the brain

Definition of brain plasticity

The brain’s ability to change and adapt as a result of experience.

What does brain plasticity play an important role in?

Brain development and behaviour.

Contrary to old research, what has recent research demonstrated about the brain?

That the brain continues to create new neural pathways and alter existing ones throughout people’s whole lives, to adapt to new experiences as a result of learning.

Define functional recovery.

The recovery of abilities and mental processes that have been compromised as a result of brain injury or disease.

The brain moves functions from a damaged area of the brain after trauma to other undamaged areas.

PLASTICITY: there are many different types of experiences that can alter neural organisation. What are the factors that are known to do this?

Life experience

Video games

Meditation.

As people gain new life experiences, what happens with nerves and neurons?

Frequently used nerve pathways develop stronger connections, whereas rarely used neurons eventually die.

What is the brain able to do by developing these new connections and pruning away weak ones?

Constantly adapt to a changing environment.

However what also happens as a result of age increasing?

There is a natural decline in cognitive functioning with age that can be attributed to changes in the brain.

How have researchers tried to reverse this natural decline effect?

They have looked for ways in which new connections can be made in later life.

Eg Boyke (2008) found evidence of brain plasticity in 60 year olds who were taught a new skill - juggling:

They found an increase in grey matter in the visual cortex. Although when practicing stopped, these changes were reversed.

What does playing video games result in making in the brain?

Many different complex cognitive and motor demands.

Explain Kühn’s (2014) study into video games - PROCEDURE

Kühn compared a control group with a video game training group that was trained for two months for at least 30 mins a day on the game Super Mario.

Explain Kühn’s (2014) study into video games (RESULTS)

They found a significant increase in grey matter in various brain areas - including the hippocampus and cerebellum.

This increase wasn’t evident in the group that didn’t play Super Mario.

Explain Kühn’s (2014) study into video games (CONCLUSION)

The researchers concluded that video game training had resulted in new synaptic connections in brain areas involved in spatial navigation, strategic planning, working memory and motor performance.

These were skills that were important in playing the game successfully.

How has Medication been demonstrated to change the inner workings of the brain?

By research on Tibetan monks (Davidson, 2014).

Explain the procedure of this study.

Davidson compared 8 practitioners of Tibetan meditation with 10 student volunteers with no previous meditation experience.

Both groups were fitted with electrical sensors and asked to meditate for short periods.

Explain the findings of the study.

The electrodes picked up much greater gamma wave activation in the monks.

The students only showed a slight increase in gamma wave activity while meditating.

Explain the conclusions of the study.

The researchers concluded that meditation changes the workings of the brain in the short term, but may also produce permanent changes - based upon the fact that the monks had far more gamma wave activity than the control group even before they started mediating.

FUNCTIONAL RECOVERY AFTER TRAUMA: What did researchers study in the 1960s?

They studied cases in which stroke victims were able to regain functioning.

What did the researchers discover?

That when brain cells are damaged or destroyed (eg during a stroke), the brain re-wires itself over time so that some level of function can be regained.

This is functional recovery.

How did this appear to happen?

Other parts of the brain appeared to take over the functions that were lost as a result of trauma.

Neurons next to the brain areas formed new circuits that resumed some sort of the lost function.

Where do regenerative developments in brain function arise from?

The brain’s plasticity and its ability to change structurally and functionally following trauma.

What are the two ways the brain is able to do this?

Neuronal unmasking and stem cells.

Explain neuronal unmasking (Part 1)

‘Dormant synapses’ in the brain are synaptic connections that exist, but their function is blocked.

Under normal conditions, these synapses are ineffective, as the rate of neuronal input to them is too low for them to be activated.

Explain neuronal unmasking (Part 2 - unmasking)

Increasing the input rate to dormant synapses (happens when a surrounding brain area becomes damaged) can then open (‘unmask’) these dormant synapses.

This can open connections to brain regions that aren’t normally activated - creating a lateral spread of activation. This, over time, gives way to the development of new structures.

What are stem cells?

Unspecialised cells that have the potential to take on many different functions - including taking on the characteristics of nerve cells.

There are many views on how stem cells provide treatments for brain damage. What are these?

1. Stem cells implanted onto the brain directly replace dead/damaged cells

2. Transplanted stem cells secrete growth factors that somehow ‘rescue’ the injured cells

3. Transplanted cells form a neural network, which links an uninjured brain site, where new stem cells made, with the damaged region of the brain.

Plasticity positive eval

Human studies taxi driver research support - Maguire (2000) discovered that taxi drivers’ brains had far more grey matter than control participants in the posterior hippocampus, compared to control participants. This is a result of them learning the roads in London. Also, the taxi drivers who had done it for the longest had the most grey matter. This proves that life experience leads to high plasticity.

Animal studies research support - Kempermann (1998) found evidence of an increased number of new neurons (in the hippocampus) in the brains of rats housed in complex environments compared to rats hostess in laboratory cages. This shows evidence of plasticity - although animal studies can’t be generalised to humans.

Plasticity positive eval

Boyke (2008) found evidence of brain plasticity when he taught 60 year-olds the new skill of juggling. Although these changes were reversed when practicing stopped.

Functional recovery positive eval

Animal studies research support - Tajiri (2013) discovered that rats with stem cell transplants after traumatic injury showed lots of clear development after 3 months in neuron-like cells in the injured area.

The control group of rats (no stem cells) showed zero development of neuronal cells. This proves that stem cells work. But animal studies can’t be generalised.

Functional recovery negative eval

Functional recovery reduces with age - so elderly people wont be able to fix their brain functions after trauma as well as younger people (Huttenlocher, 2002)