Plasticity and Functional Recovery (Biopsychology)

Question 1

Plasticity

Answer 1

the brain’s tendency to change and adapt as a result of experience and new learning

Question 2

Denervation + Denervation super/hypersensitivity

Answer 2

Denervation: loss of nerve supply. Inactivity and antrophy of muscle fibres

Denervation super sensitivity/hypersensitivity: is the sharp increase of sensitivity of post-synaptic membranes to a chemical transmitter after denervation. It is a compensatory change

Question 3

Synaptic Pruning

Answer 3

the brain’s tendency to change and adapt (mould) functionally….

During infancy, the brain experiences a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 by the age of 2-3. This is twice as many as adults have.

As we age, rarely used connections are deleted and frequently used connections are strengthened in cognitive pruning.

Question 4

How does plasticity work?

Answer 4

• the brain is able to rewire and reorganise by forming new synaptic connections close to the area of damage
• secondary neural pathways that would not typically used to carry out certain functions are ‘unmasked’ to enable functioning to continue
• this process is supported by a number of structural changes

Question 5

Axonal sprouting

Answer 5

new nerve endings grow and connect with undamaged areas

this is followed by the reformation of blood vessels

Question 6

Increased brain stimulation

Answer 6

if neurones are damaged, neighbouring neurones are also affected (works the same for the hemispheres).erefore, you need to stimulate the undamaged neighbouring neurones or healthy hemisphere to aid plasticity,
After trauma,this can happen very quickly (spontaneous recover) and then it slows down

Question 7

Recruitment of homologous areas

Answer 7

recruitment of homologous areas on the opposite hemisphere to do specific tasks, e.g. if Broca’s area was damaged then an area on the right might take over

Question 8

Elanor Maguire et al 2000

Answer 8

studied the brains of London taxi drivers using MRI

found significantly more grey matter in the posterior hippocampus than in the matched control group

the longer they had been taxi drivers, the greater the structural difference

Conclusion: there is a positive correlation between the knowledge required to be a taxi driver and the length of time they’ve been doing the job, and the amount of grey matter in the posterior hippocampus

Only a correlation though

Question 9

Draganski et al 2006

Answer 9

Draganski et al 2006 imaged the brains of medial students three months before and after their final exams
• learning induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of the exam

Question 10

Mechelli et al 2004

Answer 10

found larger parietal cortex in the brains of people who were bilingual compared to matched monolingual controls

Question 11

What factors affect the recovery of the brain after trauma and why?

Answer 11

trauma
stress
social interaction
meditation
emotions
learning
paying attention
diet
exercise
new experiences

Question 12

Gabby Giffords

Answer 12

was placed in a coma after being shot. Within months, with the ad of physical rehabilitation, Gabby was able to walk under supervision with perfect control of her left arm and leg and able to write with her left hand. She could read, understand and speak in short phases. Doctors suggested that Gabby’s progress would place her in the top 5 percent of people recovering from serious brain injury- remarkable example of the brain’s ability to heal itself.

Question 13

(Evaluations of plasticity and functional recovery) Practical application

Answer 13

understanding plasticity has contributed to the field of neuro-rehabilitation

following illness or injury to the brain, spontaneous recovery tends to slow down after a number of weeks, so physical therapy may be required
-including movement therapy and electrical stimulation to counter the deficits in motor and/or cognitive function

this shows the brain has the ability to fix itself through neuroplasticity and rehabilitation

As people age, this becomes slower

Question 14

(Evaluations of plasticity and functional recovery) Age and Plasticity

Answer 14

the brain has a greater propensity for reorganisation in childhood, as it is constantly adapting to new experiences and learning

Bezzola et al. 2012 demonstrated how 40 hours of golf training produced changes in the neural representation of movement in participants aged 40-60

using fMRI the researchers observed reduced motor cortex activity in the novice golfers than controls, suggesting more efficient neural representations after training

this supports how neuroplastiity changes as we age but does continue throughout our lifetime

Question 15

(Evaluations of plasticity and functional recovery) Support from Animal Studies

Answer 15

Hubel and Wiesel 1963 involved sewing one eye of a kitten shut and analysing the brain’s cortical responses. It was found that the area of the visual cortex associated with the shut eye was not idle but continued to process information from the open eye

this research supports the brain’s ability to compensate for itself

however, the research cannot be generalised to humans

Question 16

(Evaluations of plasticity and functional recovery) Negative Plasticity

Answer 16

the brain’s ability to rewire itself can have maladaptive behavioural consequences

prolonged drug use has been shown to result in poorer cognitive function as well as increased risk of dementia

60-80% of amputees have been known to develop phantom limb syndrome- the experience of sensations in the missing limb

these sensations are unpleasant, painful and are thought to be due to cortical reorganisation in the somatosensory cortex (Ramachandran and Hirstein 1998)

Question 17

(Evaluations of plasticity and functional recovery) The concept of Cognitive Reserve

Answer 17

there is evidence to suggest a person’s educational attainment may influence how well the brain adapts after injury

schneider et al 2014 discovered that the more time brain injury patients had spent in education (which was taken as their cognitive reserve), the greater their chances of disability free recovery (DFR)

2/5 of patients studied who achieved DFR had more than 16 years education compared to about 10% who had less than 12