Plasticity and functional recovery of the brain after trauma

What is plasticity?

Plasticity is the ability of the brain to change and develop as a result of our experience and learning

What is functional recovery?

Functional recovery describes how the brain can recover after trauma and brain injury

At what age does the peak number of synaptic connections occur and how many is it? (2)

age 2-3, 15,000

What is synaptic pruning?

When synaptic connections we don’t use are deleted and connections we use a lot are strengthened

What was the aim of Maguire et al’s research?

to test whether being a cab driver in London has affected brain structure

What is the function of the posterior hippocampus?

the posterior hippocampus is the part of the brain associated with spatial and navigational skills in humans and other animals

What is included in taxi driver training that makes them as participants significant to study?

Taxi drivers have to perform ‘The Knowledge’ test that assesses their ability to recall the names and locations of the streets in London

What were the characteristics of the taxi driver participants? (2)

16, right-handed

What method did Maguire use?

Maguire performed MRI scans on 16 right-handed London taxi drivers compared to a matched control group of bus drivers

Why were bus drivers of London used as a matched control group to compare the taxi drivers to? (2)

bus drivers follow a set route, so they do not have to remember the same street names and locations the taxi drivers do

What were the findings of Maguire’s experiment related to grey matter?

London taxi drivers had a significantly greater volume of grey matter in the posterior hippocampus than the matched control group of bus drivers

What were the findings of Maguire’s experiment related to posterior hippocampus size? (2)

The longer the participant had been a taxi driver the larger their posterior hippocampus, as they use the posterior hippocampus to learn street names and routes

What conclusion can be made from these findings?

There was a positive correlation between how great the volume of grey matter was and how long they had been in the job

What do the findings suggest about brain structure?

The learning of routes and street names the taxi drivers have done altered the structure of their brains

Why can we not conclude causality between the volume of grey matter and the time spent being a taxi driver? (3)

it is only correlational, it may be that the individuals chose to be taxi drivers because they had a naturally larger hippocampus and therefore were very good at spatial awareness, not that the length of time they worked as taxi drivers caused them to develop a larger posterior hippocampus

What did Kuhn et al find out?

They found there was a significant increase in grey matter in various regions of the brain after participants played video games over a period of two months for 30 minutes a day compared to the control group

What do Kuhn et al findings suggest? (2)

evidence of brain plasticity, how experience can result in structural changes in the brain

What did Draganski et al find? (3)

they imaged the brains of medical students three months before and after their final exams, learning induced changes were seen in the posterior hippocampus and parietal cortex, assumed to be as a result of the exam

What did Mechelli et al find?

bilingual people had a larger parietal cortex compared to non bilingual people

How has neural plasticity been shown? (4)

recovery of the brain after trauma due to physical injury or illness, healthy areas of the brain may take over the functions of affected areas, neuroscientists suggest this occurs quickly after trauma then slows down in following weeks and months, when the individual may require rehabilitation therapy

What are structural changes that can occur during functional recovery? (3)

recruitment of homologous areas, reformation of blood vessels, axonal sprouting

What is the recruitment of homologous areas?

areas on the other side of the brain take over specific tasks the affected areas cannot currently carry out

What is the reformation of blood vessels? (2)

where blood flow is increased to the affected area, supplying the damaged area with oxygen and nutrients to help repair it

What is axonal sprouting?

growth of new nerve endings that connect with other undamaged nerve cells to form new neuronal pathways

What happened to EB as investigated in the case study by Laura Danelli?

17 year old Italian boy had entire left hemisphere removed at 2 years old due to non-cancerous tumour

What happened at age 5 for EB?

language fluency improved due to intensive rehabilitation

What happened by age 17 to EB? (3)

Using brain scans, he only had minor grammar problems, his language seemed virtually normal in everyday life

What does the EB case study suggest?

language abilities can still function after trauma

What does evidence suggest about an individual’s level of educational attainment and their likelihood of brain recovery after trauma? (2)

Schneider found that the more time patient’s with brain injuries spent in education the greater their chances of a disability-free recovery, suggesting cognitive reserve is an important factor in brain recovery after trauma

What is cognitive reserve?

the brain’s ability to improvise and use alternative neural pathways maintaining normal functions regardless of trauma or injury to the brain

What evidence shows that rewiring does not always have positive consequences? (3)

prolonged drug use is shown to result in poorer cognitive functioning and increased risk of dementia later in life, 60-80% of amputees have phantom-limb syndrome where they continue to experience pain and unpleasant sensations thought to arise from cortical reorganisation in the somatosensory cortex resulting from the limb loss, therapies help to ensure rewiring is beneficial to their functioning