Neural network: a series of connected neurons.
The more time we send information along these networks, the more developed this neural network will be. This is why habits are hard to break
Neuroplasticity: the brain’s ability to reorganise itself by forming new neural connections throughout life. Neuroplasticity allows the brain to:
- compensate for injury and disease
- adjust their activities in response to new situations
The process of neuroplasticity is rather slow and involve many processes:
- axonal sprouting and dendritic branching – form new pathways: can be learning new knowledges and repair after injury
- neural pruning – deleting the neural connections that are no longer necessary or useful, and strengthening the necessary ones.
Key Study 1:
- Maguire – Taxi study
Quasi-experiment:
A – To investigate how cognitive processes may lead to neuroplasticity in the hippocampus, through the development of neural networks and neural pruning/ to see whether the brains of London taxi drivers would be somehow different as a result of the exceptional training that they have to do to be certified
M – The taxi drivers were compared with the MRI scans of 50 right-handed males who did not drive taxis. In order to take part in the study, the participants had to have completed the “Knowledge” test and have their license for at least 1.5 years. There were two different techniques used to in MRI to measure, which shows the density of grey matter and overall area of hippocampus.
R – First, MRI revealed that the posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects and the anterior hippocampi were significantly smaller. Second, showed that the volume of the right posterior hippocampi correlated with the amount of time spent as a taxi driver.
C – This shows the localised area of function for the posterior hippocampus appears to be involved when previously learned spatial information is used, whereas the anterior hippocampal region may be more involved during the encoding of new environmental layouts. It also shows the brain development of neural networks, with repetition and neural pruning through environmental influences; in other words, brain plasticity.
Critical analysis:
– Larger hippocampi might be more spatially talented and thus chose to be taxi drivers: doesn’t explain the positive correlation
The brain’s plasticity means that negative experiences, like injury and trauma, can leave their mark in potentially lasting and harmful ways. Brain plasticity occurs from the very initial environment we find ourselves in; our mother’s womb.
Key Study 2:
- Rivkin: prenatal exposure to drugs
Researchers employed volumetric MRI imaging to look at the brain structure of 35 adolescents prenatally exposed to drugs. Prenatal exposures were confirmed by a combination of maternal history, urine testing of the mother or urine or stool testing of the infants at birth.
R – reductions in cortical grey matter and total brain volumes were associated with prenatal exposure to such toxins
Additional study:
- Squeglia
A – see how “neural pruning” (e.g. synaptic pruning) correlates with cognition and behaviour.
M – This correlational study used brain scans to observe the grey matter in the brains of 185 children between 12-14 years old. The researchers also gathered data from the kids on a range of cognitive abilities, including problem solving, working memory and learning.
R – the older the children were, the less grey matter they had. This is consistent with other evidence that shows neural pruning is taking place between the ages of 12-14. They also found the thinner the parietal lobe cortex (less grey matter = more neural pruning) the better the children were at tests of learning, memory and problem solving. This is similar to other studies that suggests the neural pruning helps to improve cognitive function through “…the elimination of unnecessary synaptic connections.”
C – The process of pruning synaptic connections helps develop the neural networks associated with learning and memory.
