Brain plasticity refers to the brain’s ability to adapt and change through the creation of new neural pathways and the alteration of existing ones to adapt to new experiences due to learning. Research has found that neuronal organisation can change due to experiences and that different types of experiences ranging from life experiences, video games to even meditation can cause this.
New experiences cause nerve pathways that are frequently used to become stronger in their connections however neurons which are rarely used become weaker and eventually die out. The brain does this to keep adapting to the ever changing environment however age can also explain the decline in cognitive functioning within the brain. Life experiences have been found to reverse this effect through the teaching of new skills.Boyke et al (2008) found when 60 year olds were taught juggling, this resulted in an increase in grey matter within the visual cortex highlighting how new life experiences can result in plasticity.
Research by Kuhn et al (2014) has found video games increase grey matter in various parts of the brain including the cortex, hippocampus and cerebellum when comparing to a control group. This was believed to be because video games involve complex cognitive and motor actions which result in new synaptic connections in the brain areas responsible for spatial awareness and navigation, planning, working memory and motor performance which are important skills when playing various videogames.
Meditation has been found to affect neural activity and pathways. Davidson et al (2004) studied Tibetan monks meditating and compared to a control group they were found to have higher levels of gamma wave activity. Gamma waves are associated with increased coordination of neuron activity and the conclusion drawn from this research was meditation could affect the workings of the brain in the short-term as well as the long-term as the monks had a naturally higher gamma wave activity than the control group even before they began to meditate.
Functional Recovery After Trauma
Case studies of individuals suffering from strokes during the 1960’s have found some individuals were able to recover previous functioning to some degree after brain cells were damaged due to strokes. They found the brain was able to “re-wire” itself and create alternative neural pathways around damaged areas with other parts of the brain taking over functions which were lost. The brain is able to do this due to the brain’s plasticity and through two mechanisms known as neuronal unmasking and stem cells.
Neuronal unmasking was first identified by Wall (1977) through what he identified as “dormant synapses” within the brain. Synaptic connections exist within the brain but their functions are blocked and ineffective as the rate of neural input is too low for them to be activated. Damage to other pathways and structures causes these pathways to become “unmasked” and open the dormant synapses as new routes for neural input opening connections within the brain not normally activated. This lateral spread of activation leads to the development of new structures which take over the functions of damaged areas.
Stem cells are unspecialised cells which have the potential to develop into various types of cells with different functions which includes the functioning of nerve cells. One possible treatment involving stem cells may be to inject them into the brain to replace dead or dying cells or for those people with degenerative disorders. Alternatively stem cells can help the regeneration of damaged cells through secreting growth factors or help link an undamaged brain site with a damaged area of the brain using cells from a neural network.
Brain Plasticity Evaluation
Brain plasticity and its ability to change due to experience is supported not only through single case studies of individuals but through animal studies. Kempermann et al (1988) studied rats to see whether enriched environments could alter neurons within the brain. When rats were housed in complex environments compared to a control group of rats in a normal environment, they found those housed in a complex environment showed an increase in neurons within the hippocampus which is associated with the formation of new memories and navigation. This supports the view that life experiences can cause brain plasticity.
Research support for brain plasticity also comes from human studies demonstrating brain plasticity after exposure to enriched environments. Maguire et al (2000) studied London taxi drivers to test whether their extensive experience of spatial navigation from their profession could result in changes in the brain. MRI scans found that when compared to a control group of participants, the posterior hippocampi within the taxi drivers was much larger than that of the control groups and positively correlated with the amount of time they had spent as a taxi driver. This suggests life experiences over sufficient time and practice could cause plasticity within the brain.
Functional Recovery Of The Brain After Trauma Evaluation
Evidence for stem cells aiding recovery from brain damage comes from Tajiri et al (2013). Researchers used rats and assigned them to one of two groups; one group had rats with brain injuries while the other were a control group without injury. Only the injured rats received stem cell implants into the areas of the injured brain and after 3 months they showed clear development of neuron-like cells on the injury sites. The control group did not
display this type of improvement supporting the use of stem cells in aiding recovery after trauma. An issue with these findings however is the research was based on rats which have drastically different biology than humans and the findings may lack external validity when generalising to humans. Educational attainment has also been linked to brain recovery with patients with a college education found to be seven times more likely than those not finishing high school to be disability-free a year after having a moderate to severe brain injury (Schneider et al 2014). A retrospective study of 769 patients found 39.2% who had 16 years or more of education had recovered after one year. Over 30% who had been in education for 12-15 years had also shown improvement after one year while those who were in education for less than 12 years saw only 9.7% show improvement. Researchers concluded that cognitive reserve, which is associated with greater educational attainment, was linked to neural adaptation during recovery from brain injury.
Research evidence suggests age differences play a role in functional recovery with older age associated with reduced functional plasticity. Abilities which have thought to be fixed in childhood have been shown to be modified with enough intense training. Despite this Elbert et al (2001) concluded that neural reorganisation and functional plasticity was still greater in children than in adults.
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