plasticity & functional recovery of brain after trauma

Question 1

describe plasticity

Answer 1

• brain has the ability to change throughout life
• during infancy, the brain experiences rapid growth of synaptic connections, peaking at ~15,000 per neuron at 2-3 years old (gopnik et al. 1999)
• rarely-used connections are deleted & frequently-used connections are strengthened (synaptic pruning)
• enables lifelong plasticity as new neural connections are formed in response to new demands on the brain

Question 2

how researched plasticity

Answer 2

maguire et al. (2000)

Question 3

what did maguire et al. (2000) research

Answer 3

studied brains of london taxi drivers & found more volume of great matter in posterior
hippocampus than matched control group

Question 4

findings of maguire et al. (2000) & reasons for findings

Answer 4

• found more volume of great matter in posterior
  hippocampus of taxi drivers than matched control group
• posterior hippocampus associated with development of spatial/navigational skills
• during training, london cabbies must take complex test (‘the knowledge’) which assesses theory recall of city streets/possible routes = alters their brain structures
• the longer they’d been in the job, the more pronounced the structural difference (positive correlation)

Question 5

who had similar findings to maguire et al. (2000)

Answer 5

= draganski et al. (2006)

• imaged brains of medical students 3 months before & after their final exams
• learning-induced changes occurred in posterior hippocampus & parietal cortex

Question 6

plasticity: AO3 +) brain plasticity may be life-long ability

Answer 6

E:
- bezzola et al. (2012) showed how 40 hours of golf training caused changes in neural representations of
movement in those aged 40-60
- using fMRI, researchers observed increased motor cortex activity in novice golfers (compared to control)
- suggests more efficient neural representations after training

T: shows neural plasticity can continue throughout life

Question 7

plasticity: AO3 -) plasticity may have negative behavioural consequences

Answer 7

E:
- medina et al. (2007) showed how the brain’s adaptation to prolonged drug use led to poor cognitive functioning later on & increased risk of dementia
- 60-80% of amputees develop phantom limb syndrome, which is usually unpleasant, painful & thought to be result of cortical reorganisation in somatosensory cortex (ramachandran & hirstein 1998)

T: suggests brains ability to adapt to damage isn’t always beneficial

Question 8

describe functional recovery

Answer 8

• after physical injury/trauma, unaffected areas of the brain can adapt/compensate for damaged areas
• example of neural plasticity

Question 9

what do neuroscientists suggest about functional recovery

Answer 9

• suggest this process occurs quickly after trauma (spontaneous recovery) & slows down after several weeks/months
• may require rehabilitative therapy to further their recovery

Question 10

functional recovery (during recovery)

Answer 10

• brain rewires/reorganises itself forming new synaptic connections close to damaged area
• secondary neural pathways not used for certain functions are activated/’unmasked’ (doidge 2007)

Question 11

examples of structural changes as a result of functional recovery

Answer 11

• axonal sprouting = growth of new nerve endings to connect to other undamaged nerve cells, forming new neuronal pathways
• denervation super sensitivity = axons that do similar jobs are aroused to higher level to compensate for those lost
• negative consequences of oversensitivity (eg. pain)
• recruitment of homologous areas on opposite side of brain = specific tasks are still performed

Question 12

functional recovery: AO3 +) real-world application

Answer 12

E:
- contributed to field of neurorehabilitation
- understanding axonal growth is possible encourages new therapies
- eg. constraint-induced movement therapy for stroke patients = repeatedly practice using affected part
of their body (eg. arm) while unaffected arm is restrained

T: shows research into functional recovery is useful as helps medical professional know when interventions are
required

Question 13

functional recovery: AO3 -) level of education may influence recovery rates

Answer 13

E:
- schneider et al. (2014) revealed the more time those with a brain injury spent in education (indication of ‘cognitive reserve’) the greater their chances of disability-free recovery (DFR)
- 40% of those who achieved DFR had 16+ years in education compared to 10% who had under 12 years

T: suggests people with brain damage who have insufficient DFR are less likely to achieve full recovery