Plasticity

• What is the term for the brain's ability to modify its structure and function based on experience?

  Plasticity
• What happens to synaptic connections during infancy?

  They experience massive growth, peaking at 15,000
• What is synaptic pruning?

  Deletion of rarely used connections in the brain
• How does plasticity enable lifelong changes in the brain?

  New neural connections form in response to demands
• What did Maguire et al (2000) find about London taxi drivers?

  They had larger grey matter in the posterior hippocampus
• What is 'The Knowledge' that taxi drivers must undertake?

  A test of recall of city streets and routes
• What changes did Draganski et al (2006) observe in medical students' brains?

  Changes in the posterior hippocampus and parietal cortex
• What is functional recovery of the brain after trauma?

  Recovery of abilities lost due to brain injury
• What is neuronal unmasking?

  Activation of dormant synapses to compensate for damage
• What is axonal sprouting?

  Growth of new nerve endings connecting undamaged cells
• How does the brain recruit homologous areas during recovery?

  Similar areas on the opposite side take over functions
• What is denervation supersensitivity?

  Increased arousal of similar axons to compensate
• What is the definition of brain plasticity?

  Brain plasticity is the ability of the brain to modify its structure and function based on experience by creating new neurons and building new networks.
• How does the brain change during infancy and aging?

  During infancy, the brain experiences a massive growth in the number of synaptic connections, peaking at approximately 15,000 at age 2-3 years (twice as many as an adult). As we age, rarely used connections are deleted and frequently used connections are strengthened through synaptic pruning.
• What is the key finding from the Maguire et al. (2000) study?

  London taxi drivers had a larger volume of grey matter in the posterior hippocampus than bus drivers (control group).
• How did the Maguire et al. (2000) study demonstrate brain plasticity?

  Learning the complex spatial knowledge required for 'The Knowledge' test changed the structure of the taxi drivers' brains, and the longer they had been on the job, the bigger the structural difference.
• What was the key finding from the Draganski et al. (2006) study?

  Changes were seen in the posterior hippocampus and the parietal cortex of medical students' brains three months before and after their final exams.
• What is functional recovery of the brain after trauma?

  • Functional recovery is where the brain recovers abilities previously lost due to brain injury, which is an example of plasticity.
  • Healthy brain areas take over functions of damaged areas.
  • May occur quickly after trauma (spontaneous recovery) and then slow down.
  • Individuals may require rehabilitation to aid recovery.
• What are the processes involved in functional recovery of the brain after trauma?

  • Neuronal unmasking: Activation of 'dormant' synapses to compensate for damaged areas of the brain.
  • Axonal sprouting: Growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
  • Reformation of blood vessels
  • Recruitment of homologous (similar) areas on the opposite side of the brain to perform specific tasks.
  • Denervation supersensitivity: Axons that do a similar job become aroused to a higher level to compensate for the ones that are lost.
• What factors can influence how well a person recovers from a brain injury?

  Factors that can influence recovery include the severity of the injury, age, determination, how quickly they are treated, how they respond to treatment, if they have any other pre-existing conditions, and whether the person is male or female (women tend to have better recovery than men).
• How has knowledge of brain plasticity contributed to neurorehabilitation and treatment to aid recovery?

  Knowledge of plasticity has contributed to treatments like constraint-induced movement therapy with stroke patients, where they repeatedly practice using the affected part of their body while the unaffected arm is restrained. Experiential factors can also enhance plasticity and functional recovery, such as meditation, learning new skills, playing video games, and physiotherapy.
• What are the limitations of the Banerjee et al. (2014) study on using stem cells to treat stroke patients?

  The Banerjee et al. (2014) study only treated 5 people who had total anterior circulation stroke (TACS), and all participants in the trial recovered.
• How does age affect brain plasticity and functional recovery?

  Plasticity reduces with age. Neural reorganization is greater in children than adults, as the child's brain is constantly adapting to new experiences and learning. However, studies show that neural plasticity can happen at any age, even in older adults.
• How can negative plasticity have detrimental effects?

  The brain's ability to rewire itself can have negative consequences, such as prolonged drug use resulting in poorer cognitive functioning and increased risk of dementia, and amputees developing painful phantom limb syndrome due to cortical reorganization in the somatosensory cortex.
• How does cognitive reserve influence recovery from brain injury?

  Evidence suggests that a person's educational attainment (cognitive reserve) may influence how well the brain adapts after injury. People with more years of education had a greater chance of disability-free recovery compared to those with less education.
• What evidence for brain plasticity comes from animal studies?

  Hubel and Wiesel (1963) found that when they sewed one eye of a kitten shut, the visual cortex of the stitched-up eye shrank and the visual cortex for the open eye had expanded, demonstrating evidence for plasticity.
• What is an example of seasonal brain changes that demonstrate plasticity?

  In some animals, the brain (e.g., the suprachiasmatic nucleus) shrinks during spring and expands in autumn, demonstrating plasticity in response to seasonal changes.
• Using your knowledge of plasticity and functional recovery, explain Josie's recovery after her head injury.

  Josie's recovery is an example of brain plasticity and functional recovery. After her head injury, healthy brain areas likely took over the functions of the damaged areas, a process called neuronal unmasking. Over time, new neural connections were formed through axonal sprouting to compensate for the lost functions. Josie's young age also likely contributed to her greater capacity for neural reorganization and recovery compared to an older person with a similar injury.
• What are the key points to include in an essay on plasticity and functional recovery after brain trauma?

  • Define brain plasticity and explain how it enables functional recovery
  • Describe the processes involved in functional recovery (e.g., neuronal unmasking, axonal sprouting)
  • Discuss factors that can influence recovery, such as age, severity of injury, and cognitive reserve
  • Provide examples of research demonstrating plasticity and functional recovery (e.g., Maguire et al., Draganski et al.)
  • Explain how knowledge of plasticity has contributed to neurorehabilitation techniques
  • Acknowledge limitations of research and potential for negative plasticity