Biopsychology: Plasticity And Functional Recovery

Question 1

What is Plasticity?

Answer 1

• The brains ability to change functionally and physically in response to stimuli.
• Memories are represented within brains networks of neurons.
• Plasticity allows for these networks to be reorganised.

Question 2

What is Functional Recovery?

Answer 2

• Where the brain compensates for a loss of functionality after brain damage.
• How the brain recovers after injury.
• Axonal sprouting can occur, where the growth of new axons and the creation of new synapses occurs.
• Neuronal unmasking involves the replacement of damaged synapses by ‘unmasking’ previously unused synapses.
• Homologous area adaption occurs when the function of a damaged part of the brain in one hemisphere is relocated to its twin area in the other hemisphere.
• Cross-modal reassignment occurs when structures previously devoted to processing a particular kind of sensory input now accepts input from a new sensory method.

Question 3

What is Synaptic Plasticity?

Answer 3

• How the brain learns from experience.
• The primary mechanism through by which brains learn to reorganise themselves in response to experience.
• Refers to the ability of synapses to strengthen or weaken over time in response to increases or decreases in their activity.
• The more a synapse is strengthened, the easier it is for the Presynaptic neuron to trigger an action potential in the post synaptic neuron.

Question 4

Give an example of synaptic plasticity.

Answer 4

Positive reinforcement. Skinners rat learns to associate new actions by associating the synaptic connections and strengthening the memory of the connection between pressing the lever and receiving food.

Question 5

What are some factors affecting plasticity?

Answer 5

• Younger brains are more plastic. Meaning they’re better at learning through synaptic and functional recovery.
• Practice= the more a person practices, the more they strengthen the relevant synapses. This strengthens all forms of learning, including learning to regain a lost of function after an injury.

Question 6

How does some research demonstrate the extent to which the brain is capable of plasticity and functional recovery?

Answer 6

In one study, Sur (1992) “rewired” the brains of ferrets through surgery so that signals from their eyes fed into the auditory cortex instead of the visual cortex. Sur found that the newly rewired auditory cortex was able to process information from the ferret’s eyes. The fact that one area of the ferrets’ brains (their auditory cortex) was able to assume the
function of another damaged area (the visual cortex) provides strong evidence that brains capable of
functional recovery, as it shows how the damaged ferret brains were able to reorganize themselves by relocating the function from a damaged area of the brain to an undamaged area. Since functional
recovery is a feature of plasticity, this also demonstrates the ferret brains were plastic. This is an example of cross-modal reassignment, one of the mechanisms involved in functional recovery.However, although the ferrets in Sur’s study could “see” using their auditory cortex, their vision was extremely poor. This therefore illustrates the limitations of plasticity and functional recovery, as although the ferrets’ brains did relocate the function of the visual cortex to the auditory, this transfer was far from perfect. This limited functional recovery might be accounted for by localisation
of function. This theory holds that certain areas of the brain are specialized for certain functions, so we would therefore not expect that another area of the brain would necessarily be able to carry out the function of another damaged area of the brain

Question 7

How has research revealed the importance of age for plasticity and functional recovery?

Answer 7

Marquez de la Plata (2008) found that in patients receiving treatment for brain injury, those over
40 regained less function during treatment and were also more likely to decline in function over the next five years than those under 40. These findings demonstrate that younger brains are more capable of functional recovery than
older brains. This makes sense given that functional recovery is an aspect of plasticity, and since
younger brains are more plastic we would expect that they would be better at reorganising following
an injury. Nonetheless, this research did show that even those aged over 40 were able to achieve some functional recovery, thereby supporting the claim that all brains have some degree of plasticity and therefore are always capable of some degree of functional recovery. However, one limitation of this study is its reliance on a quasi-experiment. Since the independent variable (age) is a pre-existing difference, the researcher was unable to randomly allocate participants in this study. This undermines the study’s internal validity and so weakens its credibility as supporting evidence for the role of age in plasticity and functional recovery.

Question 8

How does the concept of the brain plasticity have socially sensitive implications for the nature nurture debate?

Answer 8

Plasticity suggests that our brains are literally shaped by our experiences, supporting the idea
that much of who we are is moulded by nurture rather than being predetermined by nature. This
perspective aligns with the behaviourist “blank slate” assumption. However, this view is socially sensitive, as it can imply that people can be entirely remoulded,
including in deeply ingrained aspects like sexuality. Such a notion could lead to harmful practices,
like conversion therapy, or unrealistic expectations about human changeability. Importantly, this
interpretation overstates the power of plasticity, as it is evident that not all aspects of a person, such
as their sexual orientation, can be altered through experience alone.