chapter 5

• Neuroplasticity


  The ability of the brain and other parts of the nervous system to change in response to experience
• Neuroplasticity


  • Enables us to learn, remember, and meet the demands of everyday life
  • Occurs at the synapse, the site where neighbouring neurons communicate by sending neural signals to one another
• Experience-expectant plasticity


  Brain change in response to an environmental experience that is ordinarily expected
• Experience-expectant plasticity

  • Exposure to language early in life, exposure to light for normal development of the visual cortex
• Experience-dependent plasticity


  Brain change that modifies some part of its neuronal structure that is already present, dependent on exposure to various environmental experiences that are unique to the individual
• Experience-dependent plasticity


  • Those who learn a string instrument have a larger area in the somatosensory cortex dedicated to the fingers
  • Exposure to speed or ice can alter synaptic connections
• Functional/adaptive plasticity


  Experience-dependent plasticity that occurs following a brain injury, allowing the brain to compensate for lost functioning and maximise remaining functions
• The brain is more plastic in infancy and early childhood than when we're older
• Neuroplasticity


  • Occurs at the neuronal level through various changes to the neuron structure, synaptic connections and functions
  • Through the process of rerouting, an undamaged neuron may seek out a new connection with a new active neuron, allowing the brain function to continue via this new connection
  • This new connection needs to be repeatedly stimulated through repetitive activity to make the new synaptic connection stronger
  • The younger the age of the patient, the more likely it is that the skill will be 'relearned' through this new pathway
• Functions can be reassigned


  To different, undamaged areas of the brain to compensate for the damaged area
• Until recently, scientists thought that we were born with all the neurons we will ever have
• Neurogenesis


  The production of new neurons, occurring in the hippocampus, amygdala and ventricles of an adult brain
• Brain injury


  Refers to any brain damage that impairs or interferes with the normal functioning of the brain, either temporarily or permanently
• Acquired brain injury


  Damage that can be caused by an accident, intentional blow, violent shaking of the head, stroke, alcohol and drugs, brain surgery, infection, inflammation or disease
• Sudden onset brain injury


  When it occurs abruptly, often at a single point in time
• Insidious onset brain injury


  When it gradually develops over a period of time in a gradual way
• Severity of brain injury


  • Mild: Good recovery, limited concentration, able to return to work
  • Moderate: Improvement over time, difficulties with coordinating movements, inability to organise, may require different line of work
  • Severe: Decreased movement control, decreased ability to communicate, requires support with daily living, unable to return to work
  • Very Severe: Unable to control movement, unable to communicate, requires 24-hour support, unable to work
• Traumatic brain injury

  Type of acquired brain injury caused by a blow to the head or by the head being forced to move rapidly forward or backward, usually with some loss of consciousness
• Causes of traumatic brain injury

  • Motor vehicle accidents
  • Falls
  • Assault
  • Sporting accident
  • Gunshot wounds
  • Violent shaking
• Phineas Gage

  A man who suffered a traumatic brain injury in 1848 when an iron rod went through his cheek and out the top of his skull, yet he survived
• Immediately after the injury, it appeared that no damage had been done to Gage's physical or mental abilities, but he suffered changes to his personality
• Injuries to the frontal lobes can cause

  • Biological changes: Reduced ordinary voluntary and spontaneous movements, blank facial expressions, minimal head and eye movement
  • Psychological changes: Lack of empathy, lack of emotional response, bouts of extreme euphoria, impulsive behaviour, disregard for social conventions, verbal and physical aggressiveness
  • Social changes: Socially inappropriate behaviour, difficulty in establishing new social relationships
  • Problems with motor activities, reduced response to pain, problems with creative thinking and problem solving, forgetfulness with tasks that require continuous attention, inability to plan activities
• Aphasia


  A language disorder resulting from an acquired brain injury to an area responsible for language production or processing
• Broca's aphasia

  A disorder involving difficulty with speech production, resulting in broken speech. Reading and writing is also impaired.
• Wernicke's aphasia

  A type of aphasia whereby a person has considerable difficulty understanding spoken or written language and speaking in a meaningful way (in a way that makes sense)
• Stroke

  When blood supply is interrupted to part of the brain, the most common cause of an acquired brain injury
• Types of stroke


  • Ischaemic: where blood supply is restricted or stopped due to a blockage
  • Haemorrhagic: where a blood vessel bursts causing bleeding in the brain
• The type of stroke, the impacted brain area, and the severity of the stroke can all influence the potential brain damage
• Neurological disorders

  Diseases of the nervous system involving any division of the nervous system (brain, spinal cord, or the peripheral nervous system)
• Epilepsy

  A neurological condition involving recurrent, spontaneous seizures brought on by interference in normal brain activity
• Chronic Traumatic Encephalopathy (CTE)

  A progressive, fatal brain degeneration and fatal condition thought to be caused by repeated blows to the head and repeated episodes of concussion
• Symptoms of CTE

  • Loss of memory
  • Mood changes
  • Personality changes
  • Confusion/disorientation
  • Motor impairment
• There is currently no test or scan to diagnose CTE in a living person - it must be diagnosed on autopsy