6 plasticity and functional recovery ao3

plasticity

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

functional recovery

describes how the brain can recover after trauma and brain injury.

15k synaptic connections at age 2-3

synaptic pruning

as we age, connections that we dont use are deleted and connections we use are strengthened

RS into brain plasticity - maguire et al

Aim:
To investigate whether being a London taxi driver changes brain structure, particularly the posterior hippocampus, which is involved in spatial and navigational skills.

Method:

• MRI scans of 16 right-handed London taxi drivers.

• Compared with a matched group of bus drivers, who follow fixed routes.

• Taxi drivers had to learn “The Knowledge” — London streets, routes and locations.

Results:

• Taxi drivers had significantly more grey matter in their posterior hippocampus.

• There was a positive correlation between time spent as a taxi driver and hippocampal volume.

Conclusion:
Learning complex routes may alter brain structure, supporting brain plasticity.

strengths on maguire london taxi drivers

• Control group allows us to say that there is a significant difference between taxi drivers and others (same mean age and all right handed)= good internal validity.

• Use of scientific, objective measurements (MRI)

• An attempt to study a real-world phenomena (natural experiment).

• Good mundane realism = external validity

weaknesses on maguire london taxi drivers

• No female taxi drivers used in sample - generalisability is poor due to beta gender bias (the assumption that findings from males can be applied to everyone).

• Issue of correlational research - ability to prove cause and effect. We can't be 100% sure that the difference is due to the 'knowledge', they weren't tested before. They could have been taxi drivers because of their already existing difference.

• HOWEVER the further positive correlation found between length of time in the job (amount of experience) and size of hiopocamous means that causation is very likely

mechelli et al 2004

found a larger parietal cortex in the brains of bilingual people compared to non bilingual people

functional recovery of the brain and trauma

brain is able to recover from trauma caused by physical injury or illness.

healthy brain areas may take over the functions of the areas that have been affected

how does brain recovery work

the brain is able to reorganise and rewire itself by forming new synaptic connections

structurall changes that support brain recovery

axonal sprouting: growth new nerve endings connecting with other undamaged nerve cells to form new neuronal pathways

reformation of blood cells: blood flow is increased to the affected areas

recruitment of homologous areas: on the other side of the brain take over specific tasks

research supporting functional recovery

case study EB - Laura Danelli et al

• inv a 17 italian boy who had his entire left brain hemisphere removed at 2 (non cancerous tumour)

• age 5, his language fluency improved due to intensive rehabilitation and by age 17, using brain scans he had minor problems with grammar but EB appeared virtually normal

• suggest language abilities can still function after severe trauma such as removal of L hemisphere

factors affecting functional recovery

• education: schneiders cognitive reserve is the term for he finding that the more years spent in education the higher the chance of disability free recovery

• age: younger of brain damage, greater chance of disability free recovery

• gender: women have higher chance of disability free recovery as they have higher connectivity between two hemispheres

negative consequences of brain plasticity

• Prolonged drug use → poorer cognitive functioning and increased risk of dementia later in life.

• Phantom limb syndrome: 60–80% of amputees experience sensations in a missing limb.

• This is thought to result from cortical reorganisation in the somatosensory cortex following limb loss.

• These sensations can be unpleasant or painful.

• Therapies can help make brain rewiring more beneficial for functioning.

strength: evidence

P: Research provides strong evidence that the brain is plastic and can adapt/recover after injury.

E: Maguire et al. found London taxi drivers had a larger posterior hippocampus, linked to their extensive spatial/navigation training.

E: Also Danielli case study of EB showing the extent of reorganisation is possible. This shows the brain can change its structure in response to experience and learning.

L: Therefore, the evidence supports the idea that the brain is highly adaptive and capable of plasticity and functional recovery.

weakness: ind differences

P: Recovery varies between individuals, and plasticity tends to decrease with age.

E: Marquez de la Plata et al. (2008) found older patients (40+) recovered less function following brain trauma than younger patients.

E: However, Bezzola et al. (2012) found that 40 hours of golf training produced changes in the motor cortex of people aged 40–60.

L: This suggests plasticity continues throughout life, although age can affect the extent and speed of recovery.

application: strength

P: Research has improved neurorehabilitation for people with brain damage.

E: Spontaneous recovery is fastest during the first few weeks, so physical therapy can be introduced early to encourage further recovery.

E: Rehabilitation can help the brain reorganise and maintain improvements in functioning.

L: This demonstrates the usefulness of research because understanding plasticity has helped develop treatments for people with brain injuries.