Explain one example of neuroplasticity. [8]
The relationship between physiological processes and the environment is bidirectional; the way we
interact with the environment is regulated by our physiology and in turn environmental interaction
can affect our physiological processes, and hence our behaviour. An effect of the environment on
physiological processes is brain plasticity. This process explains how environmental stimulation
can change and modify the structure of the brain especially the cerebral cortex. This can be
observed in rats and the brain structure of neglected children. This makes sense as the brain is
constantly changing throughout one’s life, so it is to be expected that this is in response to one’s
experiences and stimulation. Essentially, brain plasticity is the brain’s ability to rearrange
connections between neurones so that changes occur in the brain’s structure in response to the
environment. High levels of stimulus and numerous learning opportunities at the appropriate times
lead to a high density of neural connections. Therefore, every time we learn something new, the
neurones connect to create a new trace in the brain, this is called dendritic branching and happens
in response to environmental stimulus. Dendrite branches used more often become more
established and those used less often weaken. Synaptic pruning is when we lose connections
which we no longer need to improve the efficiency of ones we have, it enables the brain structure
to change dependant on which areas of the brain are stimulated most.
Maguire et Al aimed to investigate if changes in the brain could be detected in those with
extensive navigation experience. This was a Quasi experiment with a naturally occurring variable
and used London taxi drivers as participants as their job requires extensive use of spacial
navigation skills. All London taxi drivers are required to take a two-year training course which
results in them being able to find their way around the city without a map. This is known in the
business as ‘Gaining the Knowledge.’ Group one consisted of 16 right handed male London taxi
drivers, with the average age of 44, all licensed for more than 18 months with an average time as
a taxi driver of 14.3 years. Group 2 consisted of 16 right handed, male, age matched non taxi
drivers. MRI scans of fifty healthy right handed male non taxi drivers aged 33-61 were analysed to
establish a comparison database of ‘average hippocampi.’ MRI scans of group one and two were
then analysed and compared to this database. The findings show an increased volume of grey
matter in the brains of the London taxi drivers compared with controls in two brain regions, the
right and left hippocampus. The increased volume was found in the posterior hippocampus which
is associated with spatial memory. The non-taxi-drivers had increased volume in the anterior
hippocampi, indicating a redistribution of matter in response to the demands of ‘Gaining the
Knowledge’, and that the mental map of the City of London may be stored in the posterior
hippocampi. This therefore supports the effect of the environment on brain plasticity, more
specifically how a frequent use of spatial navigation skills can increase the posterior hippocampus
volume.
The suggestion that environmental factors can induce structural brain changes has positive
implications for rehabilitation of those suffering from brain damage, and shows that physiological
processes do not operate in isolation.
The relationship between physiological processes and the environment is bidirectional; the way we
interact with the environment is regulated by our physiology and in turn environmental interaction
can affect our physiological processes, and hence our behaviour. An effect of the environment on
physiological processes is brain plasticity. This process explains how environmental stimulation
can change and modify the structure of the brain especially the cerebral cortex. This can be
observed in rats and the brain structure of neglected children. This makes sense as the brain is
constantly changing throughout one’s life, so it is to be expected that this is in response to one’s
experiences and stimulation. Essentially, brain plasticity is the brain’s ability to rearrange
connections between neurones so that changes occur in the brain’s structure in response to the
environment. High levels of stimulus and numerous learning opportunities at the appropriate times
lead to a high density of neural connections. Therefore, every time we learn something new, the
neurones connect to create a new trace in the brain, this is called dendritic branching and happens
in response to environmental stimulus. Dendrite branches used more often become more
established and those used less often weaken. Synaptic pruning is when we lose connections
which we no longer need to improve the efficiency of ones we have, it enables the brain structure
to change dependant on which areas of the brain are stimulated most.
Maguire et Al aimed to investigate if changes in the brain could be detected in those with
extensive navigation experience. This was a Quasi experiment with a naturally occurring variable
and used London taxi drivers as participants as their job requires extensive use of spacial
navigation skills. All London taxi drivers are required to take a two-year training course which
results in them being able to find their way around the city without a map. This is known in the
business as ‘Gaining the Knowledge.’ Group one consisted of 16 right handed male London taxi
drivers, with the average age of 44, all licensed for more than 18 months with an average time as
a taxi driver of 14.3 years. Group 2 consisted of 16 right handed, male, age matched non taxi
drivers. MRI scans of fifty healthy right handed male non taxi drivers aged 33-61 were analysed to
establish a comparison database of ‘average hippocampi.’ MRI scans of group one and two were
then analysed and compared to this database. The findings show an increased volume of grey
matter in the brains of the London taxi drivers compared with controls in two brain regions, the
right and left hippocampus. The increased volume was found in the posterior hippocampus which
is associated with spatial memory. The non-taxi-drivers had increased volume in the anterior
hippocampi, indicating a redistribution of matter in response to the demands of ‘Gaining the
Knowledge’, and that the mental map of the City of London may be stored in the posterior
hippocampi. This therefore supports the effect of the environment on brain plasticity, more
specifically how a frequent use of spatial navigation skills can increase the posterior hippocampus
volume.
The suggestion that environmental factors can induce structural brain changes has positive
implications for rehabilitation of those suffering from brain damage, and shows that physiological
processes do not operate in isolation.
