Plasticity

Plasticity

The brain’s tendency to change and adapt as a result of experience and new learning.

Involves the growth of new connections

Gopnick research

The number of synaptic connections in infancy grows rapidly and peaks at 15000 at 2-3 years old. Goes down to 7500 in adult brains

As we age, unused connections are deleted and frequently used ones are strengthened. This is known as synaptic pruning.

This synaptic pruning allows for lifelong plasticity where new neural connections are formed in response to new demands on the brain.

Maguire taxi drivers study

Procedure

16 right handed male taxi drivers with different years on the job and training time. Compared with 50 controls matched with gender, age range and handedness.

Used MRI scans to measure hippocampal volume.

In a correlational analysis, 2 variables were measured in 15 taxi drivers and 15 controls: Time spent as taxi drivers and hippocampal volume.

Maguire taxi drivers study

Results and Conclusions

Posterior hippocampal volume was larger in taxi drivers. Anterior hippocampal volume was smaller.

Positive correlation between hippocampal size and years spent as a taxi driver for posterior region and a negative correlation for the anterior region.

The posterior hippocampus stores spatial information and grows when used more

S Bezzola

Subjects aged 40-60

Given 40 hours of golf training

Produced changes in the neural representation of movement.

Used an fMRI scan. Found reduced motor cortex activity in the golfers compared to a control group. More efficient neural representations after training.

Suggests that neural plasticity can continue throughout the lifespan

S Tang

Participants given 4 weeks of intensive meditation training and then given a MRI scan.

Found increased white matter (volume) in the anterior cingulate cortex (responsible for self-control)

W Negative plasticity

Through negative behaviours, plasticity doesn’t happen and brain damage is irreversible.

Prolonged drug abuse can lead to permanent rewiring of the brain and result in other disorders like Wernicke Korsakoff’s syndrome

Suggests that the brain’s ability to adapt to change isn’t always beneficial.

W Maguire

Ethical issues

Informed consent.

MRI scanners aren’t good for people with metal implants as they will magnetise to it.

Confined space and noisy - people may find this unpleasant or frightening.

Participants would need to be given sufficient details of the procedure to be informed and give consent. Controls were not given unnecessary scans as their data was retrieved from existing stores.