Plasticity, Recovery, and Rehabilitation of the Adult Brain Flashcards
What can neural plasticity be studied through?
- Observable behaviour
- Cerebral maps
- Synaptic organization
- Physiological organization
- Molecular structure
- Mitosis
What happens in the prism adaptation? What does this tell us?
- Subjects fitted with prisms can adapt to the shifted visual world
- Neural changes occur in the premotor cortex and visual cortex
- Changes disappear after prism removal
- Inferring plasticity from observable behaviour
What is the evidence for plasticity in cortical maps?
- Memory and sensory maps can be altered by experience
- Evidenced by changes in the motor cortex of monkeys after making digit movements
- Musicians show an increase in scale representation
- Blind individuals show an increase in auditory area
- Alteration of the somatosensory cortex with changes in afferent input (cutting the afferent nerve of one or more digits)
- Focal hand dystonia (loss of motor control in a digit after making repetitive synchronous movements)
- Reorganization of somatosensory maps after amputation
What is the evidence for plasticity in synaptic organization?
- Computational Challenge
- Cells with more challenging tasks to complete are more complex
- Individual difference in cell complexity based on life experiences (e.g., typist - more complex cells in the finger region)
What is the evidence for plasticity in physiological organization?
- Long-term potentiation
- Enhanced synaptic transmission after electrical stimulation of a cell
- Leads to changes in dendritic length and spine density
- Model of how learning occurs
What is the evidence for plasticity in molecular structures?
-Gene-chip arrays (allows researchers to see what genes are affected by certain experiences)
What evidence does mitotic activity provide for plasticity?
- Adult brain can manufacture new neurons
- Olfactory bulb (stem cells in the lateral ventricles generate new olfactory bulb cells through mitosis)
- Hippocampus (new cells develop from the granule-cell layer and the hilus)
- Survival of neurons are affected by many factors
What is the downside of brain plasticity?
-Exposure to drugs produces alterations in dendritic length and spine density (addicts and prefrontal morphology)
What are the environment and drug interactions in experience dependent changes?
- Stimulant drugs block the dendritic changes seen after exposure to a complex environment
- Complex environments change the response to drugs
- Stress (changes dendrite morphology and neurogenesis; interactions with experience-dependent changes in the brain)
Can plasticity support functional recovery after injury?
-More so compensation compared to recovery. Do not recover missing brain areas (e.g., three-legged cats compensate for missing leg)
What is ischemia? What happens during ischemia?
- Happens with brain injury
- Loss of blood supply to an area of the cortex
- In the first seconds changes in pH balance and in the cell membrane occur
- Massive release of glutamate
- Open Ca+ channels
- mRNA is stimulated; protein production is altered
- Tissue becomes inflamed and swollen
What is diaschisis?
- Results from ischemia
- Loss of function of an area separate from where the injury occurred (connected by neurons)
- Leads to changes in the localized tissue and surrounding tissue
- Changes in cell metabolism may persist for days
- Can be treated with anti-inflammatory drugs or neuroprotectants
Which patients show the most recovery from aphasia?
- Head injury patients
- Deficits are least severe in anomic patients; most severe in global aphasics
- Progress to other stages in recovery, but often stop in anomic stage (difficulty naming objects)
What are some examples of the types of recovery from surgical lesions to the brain?
- Dorsolateral frontal lesions (no recovery in card sorting)
- Right temporal lesions (no recovery on the Rey Figure)
- Bilateral temporal lobe removal (no recovery)
- Left temporal lesions (significant improvement after 5-20 years)
What are some examples of functional restitution in every day life?
- When employment is used as a measure of recovery, an 80% recovery rate is found
- Social relationships and leisure activities suffer (relationships with siblings suffer the most)
- Measures of recovery often overlook the coping mechanisms the person is using
