plasticity and functional recovery of the brain after trauma

Question 1

when does the amount of synaptic connections peak in infancy?

Answer 1

15,000 at 2-3 years

Question 2

what is deleted as we age? and what is strengthened? what is this called?

Answer 2

rarely used connections are deleted.
frequently used connections are strengthened -
synaptic pruning

Question 3

what does synaptic pruning allow?

Answer 3

lifelong plasticity - new neural connections are formed in response to new demands on the brain

Question 4

what did Maguire study?

Answer 4

the brains of London taxi drivers

Question 5

what did Maguire find in her study?

Answer 5

significantly more volume of grey matter in the posterior hippocampus than in a matched control group

Question 6

what is the posterior hippocampus associated with?

Answer 6

the development of spatial and navigational skills in humans and animals

Question 7

what did ‘the knowledge’ test alter in London cabbies?

Answer 7

alters the structure of the taxi drivers brains

Question 8

what was a positive correlation in London cabbies found between?

Answer 8

the longer the taxi drivers had been in the job the more pronounced their structural difference was

Question 9

what did Draganski image?

Answer 9

brains of medical students three months before and after their final exam

Question 10

what did Learning do to the medical students brains in Draganski’s study?

Answer 10

changeswere seen to have occured in the posterior hippocampus and the parietal cortex

Question 11

Evaluation: one limitation is that plasticity can be negative…

Answer 11

• evidence shows the brain’s adaptation to prolonged drug use leads to poorer cognitive functioning later in life and an increased risk in dementia
• 60-80% of amputees have developed phantom limb syndrome - sensations in the missing limb as if it were still there - these are thought to be due to cortical reorganisation in the somatosensory cortex which occurs as a result of limb loss
• Therefore the brains ability to adapt is not always beneficial

Question 12

Evaluation: one strength is that plasticity is proven to be a life- long ability

Answer 12

• plasticity genuinely reduces with age
• Bezzola et al demonstrated how 40 hours of golf training produced changes in the neural representations of movement in ppts aged 40-60
• using fMRI researchers observed an increased motor cortex activity in novice golfers compared to a control group which suggests more efficient neural representations after training
• neural plasticity can continue throughout life span

Question 13

what can the brain usually do after trauma?

Answer 13

adapt and compensate for the damaged areas

Question 14

what is the functional recovery that occurs in the brain after trauma an example of?

Answer 14

neural plasticity

Question 15

what is neural plastciity?

Answer 15

when healthy areas of the brain may take over functions of those areas that are damaged, destroyed or missing

Question 16

what is the brain able to do after trauma?

Answer 16

rewire and reorganise itself by forming new synaptic connections close to the area of damage

Question 17

what happens to secondary neural pathways after the brain rewires and reorganises itself?

Answer 17

They are activated to enable functioning to continue often in the same way as before

Question 18

what is axonal sprouting?

Answer 18

the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

Question 19

what is denervation super sensitivity?

Answer 19

this occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost. However it can be negative consequence of oversensitivity to messages such as pain

Question 20

what is recruitment of homologous areas on opposite sides of the brain?

Answer 20

specific tasks can still be performed

Question 21

Evaluation strength: real world application

Answer 21

• understanding processes involved in plasticity has contributed to the field of neurorehabilitation
• understanding that axonal growth is possible encourages new therapies to be tried
• e.g. constraint-induced movement therapy is used with stroke patients who repeatedly practice using the affected part of their body while the unaffected part is restrained.
• research into functional recovery is useful as it helps medical professionals know when interventions need to be made

Question 22

Functional recovery limitation : it has a cognitive reserve

Answer 22

• level of education may influence recovery rates
• Schneider et al revealed the more time people with a brain injury had spent in education the greater chance a disability free recovery
• 40% of those who achieved DFR had more than 16 years education compared to 10% of those who had less than 12 years education
• people with brain damage who have insufficient DFR are less likely to achieve a full recovery