Brain plasticity Flashcards
Plasticity in the new-born brain:
The brain’s ability to change and adapt plays an important role in brain development.
By the end of the first postnatal year, the brain will have more neurons and synapses than it will have when it becomes fully mature in late adolescence/early adulthood.
In the first few years of life, the developing brain is exposed to an enormous range of experiences, environments and stimuli, including the acquisition of language.
In order for the brain to benefit from all these experiences it needs to be maximally plastic, that is, it has to respond to all these experiences by altering its organisation and structure.
Research into the plasticity of the new-born brain has revealed that the brain is highly plastic and responsive to the environment in the first few months and years after birth.
Probably the most extreme example is the hemispherectomy.
This is where one half of the brain (cerebral hemisphere) is removed, disconnected or disabled.
Occasionally, as a result of genetics, illness or a difficult birth, a baby is born with one hemisphere severely damaged.
When this whole hemisphere is removed soon after birth, incredibly as an adult that person shows few, if any, behavioural or cognitive impairments (Villablanca & Hovda, 2000).
This evidence illustrates the extraordinary plasticity of the developing brain. Functions that would normally have been carried out by the damaged hemisphere (perhaps including language) have been transferred to other areas (probably the healthy/undamaged hemisphere).
At this stage of development, the brain has sufficient neurons and synapses to cope with dramatic damage.
In the normal course of development the brain is being sculpted by the environment and experience.
The early plasticity helps adapt the brain to its environment.
Pathways and networks used regularly will survive, and those that are not will die off.
The brain finally matures around late adolescence/early adulthood.
what is Brain plasticity:
refers to the brain’s ability to modify its own structure and function as a result of experience.
Plasticity in the adult brain:
It used to be thought that brain plasticity only occurred during infancy and childhood, but more recent research has suggested that the brain continues to adapt and change in adulthood, creating new neural pathways and altering existing ones in response to new experiences.
There are many different types of experience that can have an impact on neuronal organisation; learning a new skill, playing video games, experience of spatial navigation are just some of the experiences that have been investigated in terms of their impact on neuronal organisation.
Just as in childhood, as individuals gain new experiences, nerve pathways that are used more frequently will develop stronger connections, whereas those that are rarely used or not used at all will eventually die.
Through developing new connections and pruning away weak ones the brain is able to constantly adapt to its changing environment.
What evidence is there to suggest brain plasticity occurs?
Kempermann et al (1998) – Animal research – Rats & enriched environment:
Maguire et al (2000) – London Taxi Drivers - experience of spatial navigation:
Kuhn et al (2014) – Video games
Boyke et al 2008 – Brain plasticity in older adults - Juggling:
Davidson et al (2004) – Meditation – Tibetan Monks:
Kempermann et al (1998)
Animal research – Rats & enriched environment:
These researchers used rats to investigate whether an enriched environment could alter the number of neurons in the brain.
They found that compared to rats housed in laboratory cages, those rats housed in complex environments had an increased number of neurons in the brain, particularly in the hippocampus, an area of the brain associated with the formation of new memories and the ability to navigate from one location to another.
Maguire et al (2000)
London Taxi Drivers - experience of spatial navigation:
Maguire et al studied London taxi drivers to discover whether changes in the brain could be detected as a result of their experience of extensive experience of spatial navigation.
The researchers compared the brains of taxi drivers with a control group using an MRI scanner.
The findings indicated that the posterior hippocampi of taxi drivers were significantly larger relative to those of control participants.
The posterior hippocampal volume was positively correlated with the amount of time they had spent as a taxi driver (a measure of their experience).
Kuhn et al (2014)
Video games:
Video games involve a range of different complex cognitive and motor skills.
Kuhn et al compared a control group and a training group (trained for 2 months for at least 30 minutes per day on the game Super Mario).
The findings showed a significant increase in grey matter in various brain areas including: the cortex, hippocampus and cerebellum.
This increase was not evident in the control group that did not play Super Mario.
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 – skills that were important in playing the game successfully.
Boyke et al 2008
Brain plasticity in older adults - Juggling:
Due to the natural decline in cognitive functioning that occurs with age, researchers have been interested to explore the existence of brain plasticity in older adults to see if this decline can be reversed.
Boyke et al investigated brain plasticity in 60 year olds by observing the effect on the brain of being taught a new skill (juggling).
They found an increase in grey matter in the visual cortex.
However, when practising stopped, these changes were reversed.
Davidson et al (2004)
Meditation – Tibetan Monks:
Researchers working with Tibetan monks found that meditation may change the inner workings of the brain, increasing the efficiency with which information is processed.
Davidson et al compared 8 practitioners of Tibetan meditation with 10 student volunteers with no previous experience of meditation.
Both groups were fitted with electrical sensors and asked to meditate for short periods.
The electrodes picked up much greater activation of gamma waves (which coordinate neuron activity) in the monks.
The students only showed a slight increase in gamma wave activity while meditating.
The researchers concluded that meditation not only changes the brain in the short term, but may produce permanent changes, as the monks had far more gamma wave activity than the control group even before they started meditating.
