Brain plasticity and functional recovery

Plasticity of the brain

Brain's ability to change and adapt as a result of damage, experiences and new learning

During infancy, the brain grows a number of of…

Synaptic connections

When do synaptic connections peak?

Age 3

When aged 3, we have _ as many synaptic connections as we do as adults

Twice

Synaptic pruning

a process whereby the synaptic connections in the brain that are used are preserved, and those that are not used are lost

The more your brain does something…

The stronger that function/action/memory becomes as connections become stronger

It used to be thought that developments of the brain….. but more recent research suggests…

Were restricted to childhood and adult Brian's were static in terms of function and structure, neuronal connections can change at any time in life

What animal has neuroplasticity research been carried out on?

Cats

Background and aim of cat neuroplasticity research

Investigate physiological and behavioural effects of a limited visual experience, and whether Brain development/plasticity occurs due to experience rather than nature

What type of study was cat neuroplasticity?

Lab experiment

Procedure of cat experiment

Newborn kittens placed in dark room. At 2 weeks old, placed in either horizontal or vertical striped room for 5 hours a day.

after 5 months, kittens placed for several hours a week in small well lit furnished room, and measured if kittens raised in each environment could detect vertically/horizontally aligned objects

After 7.5 months, one kitten form each IV had their neurophysiology examined

How did experimenters ensure kittens only saw intended shapes?

No corners or edges, wore wide black collar so couldn't see own body

Results of cat experiment (initial)

All kittens extremely visually impaired, demonstrated no visual placing when bought up to table top, and no startle response, all showed behaviour blindness. Showed fear when standing on surface edge

Behaviour blindness

Couldn't detect objects or contours that were aligned in opposite way to previous environment

Results of cat experiment (recovery)

Recovery of some deficiencies. After 10 hours, kittens showed visual placing and startled responses and could jump between objects, but still tried to touch things beyond their reach

Results of cat experiment (neurophysiological examination)

No evidence of blurred vision, but evidence that horizontal plane recognition cells didn't fire off from vertical IV and vice versa

Cat experiment conclusion

Brain development is clearly affected by early experiences and environmental factors not just genetics, and there is evidence of Brain plasticity.

Cat experiment strengths

high levels of control and standardisation so high level of internal validity, can establish cause and effect and could be easily replicated to test reliability due to standardisation

Cat experiment weaknesses

ethical considerations such as visually depriving kittens, however it did comply with ethical animal research guidelines

and obvious differences between cats and humans, such as humans having far more neural connections so not generalisable fully

Medical student research aim

Does extensive learning induce structural changes in the cortex of Brian's and are they long or short term changes?

Medical student research sample

38 medical students, 12 controls

Medical student method

MRI scans of brain taken 3 months before exams, 1st/2nd day of exams, and 23 of the participants had a scan 3 months after

Medical student results

Significant increase in grey matter of posterior parietal cortex of medical students, even after exam period. Increase in posterior hippocampus grey matter, which continued to increase.

Medical students conclusion

Provides support that plasticity can occur as a result of changes within the environment, so brain is plastic after childhood

Maguire taxi aim

To find out if there was a difference in the Brian scans of taxi drivers (with extensive spatial knowledge) compared to a control group of non taxi drivers

Maguire taxi sample

16 right handed licensed London taxi drivers and 50 non taxi driver right handed males

Results of Maguire taxi study

No difference in overall volume of hippocampus, but posterior hippocampal volume was bigger in taxi drivers. Amount of time as a taxi driver was positively correlated with the volume of posterior hippocampus

Maguire taxi conclusion

Provides evidence of regional plasticity in the Brian of a healthy adult as a result of extensive learning and environmental stimulus

How does Maguire taxi study establish cause and effect?

The positive correlation between time as taxi driver and size of posterior hippocampus suggests changes are acquired

What type of research was Maguire taxi driver study?

Quasi experiment

Functional recovery

Healthy brain areas take over functions of damaged areas to compensate.

Axonal sprouting

The growth of new nerve endings which connect with undamaged nerve cells to form new neural pathways

Reformation of blood vessels

This facilitates the growth of new neural pathways

Recruitment of homologous areas

using a similar area of the brain in the opposite hemisphere

Neuronal unmasking

Where 'dormant' synapses open connections to compensate for a damaged area of the brain

Studies that show scientific credibility for plasticity

Taxi drivers, medical students, kittens

Why is the idea that the structure of our brains adapting to environmental pressures classed as nature?

It is still the anatomical structure that causes a change to our behaviour, but it still contributes towards interactionist debate

Jodie who

Due to severe epileptic seizures caused by Brain swelling in right hemisphere had it removed at 3 years old. She was able to recover all functions, apart from a slight limp in her left side of her body

Practical application of brain plasticity to education

Research (meta-analysis) shows teaching people about neuroplasticity led to a growth mindset, improving motivation towards work and achievement, especially for at-risk young people in the subject of maths

Neurorehabilitation

relearning of skills lost through neural injury

Four techniques for neurorehabilitation

Physio therapy and speech therapy, brain scanning, electrical stimulation

Physiotherapy and speech therapy in neurorehabilitation

Patients are given support and guidance and exercises to perform

Brain scanning for neurorehabilitation

Provides information about which areas are damaged, informing rehabilitation

How does electrical stimulation work?

Increase activity in non-injured neurons, in order to induce neuroplastic changes

Ways of electrical stimulation

Through skin of back near spinal injury, through skull in non-invasive way, electrodes planted deep in brain

How does neurorehabilitation help support brain plasticity and idea of functional recovery?

Shows that brain can adapt and change

Age and brain plasticity research

brain trauma

Age and plasticity golf research

40 hours of golf training produced changes in the neural representation of movement in participants ages 40-60. Researchers observed reduced motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training