PSYCH; Plasticity & Functional recovery of the brain after trauma

EXAM TIP - when discussing plasticity you can mention functional recovery bc functional recovery is a major example of how the brain is 'plastic' and has the ability to adapt (plasticity)

whats meant by brain plasticity

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

this involves growth of new connections

what did Gopnick et al (1999) claim

during infancy, the brain experiences a rapid growth of synaptic connections

(about 15K per neurone at 2-3 years of age)

why are there fewer synaptic connections in adults compared to infants

bc in adults rarely used connections are deleted and frequently used connections are strengthened instead of making new ones.

whats meant by synaptic pruning

when frequently used synaptic connections are strengthened

to enable life long plasticity

who conducted research into Plasticity

Maguire et al (2000)

describe procedure Maguire’s research into plasticity

studied the brains of London taxi drivers;

part of their training - they took a complex knowledge test which asses their recall of city streets and routes

findings of Maguire (2000)

found that this learning experiences alters the structure of the taxi driver’s brains — more volume of grey matter in the posterior hippocampus.

also found that the longer the drivers had been in the job, the more pronounced/obvious the structural difference was

similar finding to Maguire et al (2000)

Draganski et al (2006);

imaged brains of med students 3 months before/after their final exams.

changed were seen due to learning in the posterior hippocampus

whats functional recovery of the brain

example of neural plasticity;

the brain’s ability to redistribute/transfer functions usually performed by a damaged area to other undamaged areas

healthy brain areas may take over functions of damaged/missing areas

whats meant by spontaneous recovery of the brain

when functional recovery of the brain can occur quickly after trauma

what happens in the brain during recovery

1. axonal sprouting - growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

2. denervation supersensitivity - when axons that do a similar job become aroused to a higher levels to compensate for ones that are lost

3. recruitment of homologous (similiar) areas on opposite side of the brain

describe axonal sprouting

a structural change that occurs during recovery of the brain;

its the growth of new nerve endings with other undamaged nerve cells to form new nueronal pathways

describe denervation supersensitivity

a structural change that occurs during recovery of brain;

when axons that do a similar job become aroused to a higher level to compensate for those that are lost

it can have a negative effect of oversensitivity to messages like pain

describe recruitment of homologous (similiar) areas on the opposite side of the brain

this means specific tasks can still be performed;

e.g. if Broca’s area was damaged on the left side of the brain, and area of the right side similiar to the Broca’s area would carry out its functions

but functions may shift back to the left side over time

strength for plasticity - supporting research

E; Maguire et al (2000) studied London taxi drivers who demonstrated that the posterior hippocampus (associated w spatial navigation) was significantly larger in taxi drivers compared to control p’s

E; This shows a positive correlation between time spent navigating and hippocampal volume, indicating that adult brain undergoes structural physical changes in reponse to environmental demands and learning

L; Therefore, this research shifts psychology becoming a highly objective and empirical science, due to the use of brain scans that provide measurable evidence of plasticity.

limitation of plasticity - may have negative behavioural consequences

E; Medina et al 2007 shown that the brain’s adaptation to prolonged drug use leads to poorer cognitive functioning as well as increased risk of dementia .

and Ramachandran&Hirstein 1998 shows 60-80% of amputees experience ‘phantom limb syndrome’ which is driven by unhelpful cortical reorganisation in the somatosensory cortex that occurs as result of limb loss

E; This proves that the brain’s ability to require itself doesnt always lead to positive functional outcomes

L; Therefore, concept of plasticity is biologically reductionist as it treats complex cognitive changes as localised ignoring psychological and social influences. Instead a more holistic approach might better explain why some individuals experience maladaptive changes vs others

strength of brain plasticity is that it may be a life long ability

E; Bezzola et al (2012) using FMRI scans observed how 40hrs of golf training increased the motor cortex activity in p’s aged 40-60 compared to a control group.

E; This suggests that neural representations become more efficient after training, supporting the concept of synaptic pruning, where new neural connections are formed in reponse to new demands on the brain.

L; Therefore, this shows that brain plasticity can continue through the lifespan.

strength of functional recovery is its real world application

E; Understanding that the brain can adapt had led to the development of physical and cognitive therapies. E.G. Constraint Induced Movement Therapy (CIMT) which forces patients to use a damaged limb while the unaffected arm is restrained, this encourages the brain to form new neural connections

E; This means that when spontaneous recovery slows down after trauma, rehabilitative therapies can stimulate the brain to recover lost functions

L; Therefore, research into functional recovery is highly valuable, as it helps medical professionals to improve quality of life for stroke survivors and brain injury patients

limitation of functional recovery is that its effectiveness relies heavily on individual differences e.g. age

E; Elbert et al noted that neural regeneration is less effective in adults, while older brains often adopt compensatory strategies to cope with loss rather than fully revering functions. Research also suggests that women may recover better from brain injury bc their brain function is less lateralised.

E; This shows that functional recovery is not a universal process, instead its highly dependent on biological and demographic factors that dictate a patient’s brain plasticity

L;Therefore, the theory cannot accurately predict the recovery outcome for every individual as it ignores individual differences.

limitation of functional recovery is that its biologically reductionist

E; Functional recovery highlights how our environment (nurture) shapes our biology (nature). The brain adapts by increasing cognitive reserve through environmental stimulation. However, it explains complex psychological and physical healing processes using only biological mechanisms like axonal sprouting.

E; This means that functional recovery oversimplifies the healing process, failing to account for psychological factors such as patient’s motivation/education that can influence their functional recovery.

L;Therefore, a purely biological explanation of the brain’s recovery is incomplete and biologically reductionist as it ignores how patients regain lost abilities