Plasticity and functional recovery of the brain after trauma
Brain plasticity
- During infancy, the brain experiences rapid growth in the number of synaptic connections it
has
- Gopnik et al (1999) says connections peak at about 15,000 per neuron at 2-3 years
- Twice as many as there are in the adult brain
- As we age, rarely used connections are deleted and frequently used connections are
strengthened – process known and synaptic pruning
- Once thought that the adult brain was not capable of change, but now we understand
synaptic pruning enables lifelong plasticity where new neural connections are formed in
response to new demands on the brain
Research into plasticity
- Eleanor Maguire et al (2000) studied brains of London taxi drivers
- Found significantly more volume of grey matter in the posterior hippocampus than in
matched control group
- This part of the brain is associated with development of spatial and navigational skills in
humans and other animals
- As part of training, London cab drivers must take a complex test called the “The Knowledge”
which assess their recall of city streets and possible routes
Findings:
- This learning experience alters the structure of the taxi drivers brains
- Longer that the taxi drivers had been in the job, the more pronounced was the structural
difference (positive correlation)
This study shed light on structural plasticity
BUT IT IS ANDROCENTRIC – doesn’t tell us anything about brain plasticity in females
Draganski et al (2006)
- Imaged brains of medical students 3 months before and after their final exams
- Learning-induced changes occurred in posterior hippocampus and parietal cortex as a result
of learning
Negative plasticity
- Plasticity may have negative behavioural consequences
- Medina et al (2007) showed that the brains adaptation to prolong the drug use leads to
poorer cognitive functioning in later life and increased risk of dementia
- Useful to know that prolonged drug use may lead to decreased plasticity
- Strength as this gives us practical application on how to delay Parkinson’s and dementia –
economic implications
Limitation
- Also, 60- 80% of amputees have been known to develop phantom limb syndrome which is
the continued experience of sensations in the missing them, as if it were still there
- Ramachandran and Hirstein (1998) say that sensations are unpleasant, painful, and are
thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a
result of limb loss
- Suggests brains ability to adapt to damage is not always beneficial
Brain plasticity
- During infancy, the brain experiences rapid growth in the number of synaptic connections it
has
- Gopnik et al (1999) says connections peak at about 15,000 per neuron at 2-3 years
- Twice as many as there are in the adult brain
- As we age, rarely used connections are deleted and frequently used connections are
strengthened – process known and synaptic pruning
- Once thought that the adult brain was not capable of change, but now we understand
synaptic pruning enables lifelong plasticity where new neural connections are formed in
response to new demands on the brain
Research into plasticity
- Eleanor Maguire et al (2000) studied brains of London taxi drivers
- Found significantly more volume of grey matter in the posterior hippocampus than in
matched control group
- This part of the brain is associated with development of spatial and navigational skills in
humans and other animals
- As part of training, London cab drivers must take a complex test called the “The Knowledge”
which assess their recall of city streets and possible routes
Findings:
- This learning experience alters the structure of the taxi drivers brains
- Longer that the taxi drivers had been in the job, the more pronounced was the structural
difference (positive correlation)
This study shed light on structural plasticity
BUT IT IS ANDROCENTRIC – doesn’t tell us anything about brain plasticity in females
Draganski et al (2006)
- Imaged brains of medical students 3 months before and after their final exams
- Learning-induced changes occurred in posterior hippocampus and parietal cortex as a result
of learning
Negative plasticity
- Plasticity may have negative behavioural consequences
- Medina et al (2007) showed that the brains adaptation to prolong the drug use leads to
poorer cognitive functioning in later life and increased risk of dementia
- Useful to know that prolonged drug use may lead to decreased plasticity
- Strength as this gives us practical application on how to delay Parkinson’s and dementia –
economic implications
Limitation
- Also, 60- 80% of amputees have been known to develop phantom limb syndrome which is
the continued experience of sensations in the missing them, as if it were still there
- Ramachandran and Hirstein (1998) say that sensations are unpleasant, painful, and are
thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a
result of limb loss
- Suggests brains ability to adapt to damage is not always beneficial
