Plasticity

Question 1

Neuroplasticity definition

Answer 1

The reorganisation of neurons and neuronal pathways in the brain - involves the generation of new neurons, new connects between pre-existing neurons and the deletion of disused neurons

Question 2

Functional recovery definition

Answer 2

Neuroplasticity in response to brain trauma, eg, through stoke or physical injury, which compensates for lost function

Question 3

Stages of neuroplasticity

Answer 3

1. Rapid growth slows at 2-3
2. From birth to 2, 40,000 synapses a second
3. Late adolescence, nearly 50% of synapses eliminated
4. thought to be static - disproven in 1998
5. Happens at any time in life due to experience

Question 4

Meditation study

Answer 4

Holzel et al - 2011 - individuals who took part in a 8 week mindfulness-based stress reduction course showed an increase in grey matter in the left hippocampus - learning and memory

Question 5

Supporting evidence

Answer 5

Eleanor Maguire - 2000 - London taxi drivers - larger posterior hippocampi
- Positive correlation between time spent as a taxi driver and volume of hippocampi

Question 6

After brain trauma

Answer 6

Brain often able to adapt and compensate for areas damaged - functional recovery may occur - healthy brain areas may take over functions

Question 7

Axonal sprouting

Answer 7

The growth of new nerve endings connect to undamaged nerve cells to form new neuronal pathways

Question 8

Denervation super-sensitivity

Answer 8

Axons that do a similar job become aroused to a higher level to compensate for ones that are lost
- Negative consequence of oversensitivity to messages such as pain

Question 9

Recruitment of homologous areas on opposite side of brain

Answer 9

Specific tasks can still be performed
- Broca’s area on left side damaged - right side equivalent would carry out functions

Question 10

Functional recovery after trauma

Answer 10

Spontaneous recovery - true healing - happens within the first few months then slows down

Question 11

Rehabilitation therapy to encourage neuroplasticity

Answer 11

• Recruiting undamaged parts of brain to perform a function previously performed by a different area
  Constraint induced manual theory - unaffected limb is constrained so the patient is forced to use the affected limb

Question 12

Negative plasticity

Answer 12

Limitation - may have negative behavioural consequences
- Brain’s adaptation to prolonged drug use - poorer cognitive functioning in later life and increased risk of dementia
- 60-80% of amputees - phantom limb syndrome
- Unpleasant, painful - due to cortical reorganisation in the somatosensory cortex
Suggests that the brain’s ability to adapt to damage is not always beneficial

Question 13

Age and plasticity

Answer 13

Strength - life-long ability
- Reduces with age
- Ladina Bezzola et al - 2012 - 40 hours of golf training produced changes in neural representations of movement in participants aged 40-60
- fMRI - observed increased motor cortex activity in novice golfers compared to control - more efficient neural representations
- Neural plasticity can continue thoughtout the lifespan

Question 14

Seasonal brain changes

Answer 14

Research - seasonal plasticity
- Suprachiasmatic nucleus - regulates sleep - particular brain shrinks in animals during spring and expands throughout autumn
- Much of the work on seasonal plasticity has been done on animals, songbirds
- Human behaviour may be controlled differently

Question 15

Real-world application

Answer 15

Strength - functional recovery
- Contributed to field of neuroehabilitation
- Encourages new therapies
- Eg constraint-induced movement
- Research into functional recovery is useful as it helps medical professionals know when interventions need to be made

Question 16

Cognitive reserve

Answer 16

Limitation - level of education may influence recovery rates
- Eric Schneider et al - 2014 - more time people with brain injury spent in education - greater chances of disability-free recovery
- 40% of those who achieved DFR - more than 16 years education compared to 10% who has less than 12 years education
- Implies that people with brain damage who have insufficient DFR are less likely to achieve a full recovery