Flashcards in Plasticity, Recovery, and Rehabilitation of the Adult Brain Deck (25):
What can neural plasticity be studied through?
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?
-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?
-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
What are the post-stroke changes found in individuals using functional imagine?
-Functional improvement can be found in the sensorimotor cortex
-Movement of the limbs activates cortex along the rim of the injury and often activates regions of the face area
-Larger regions of activation in the parietal and premotor areas during language and motor functions
-Reorganization takes place bilaterally
-Capacity for reorganization declines with increases in stroke size and age
-Considerable variability exists between patients
What was found when the digit area of a monkey's cortex was removed?
-Without rehabilitation, the shoulder and elbow area grew into that part of the motor cortex
-With rehabilitation, the finger area grew back in the cortex
What are the variables that affect recovery?
-Age (younger patients = more recovery)
-Sex and Handedness (produce differences in cerebral organization that influence outcome)
-Intelligence (higher intelligence = more recovery)
-Personality (optimism, extroversion, and easygoing patients = more recovery)
What are the six therapeutic approaches to brain damage?
-Brain tissue transplants and stem-cell induction
What is the information on the therapeutic approach of rehabilitation?
-Little information on programs
-Social interaction and environmental stimulation are important
What is the information on movement therapy?
-Constrained movement therapy
-Motor training stimulates plastic changes in the brain
What is the information on cognitive rehabilitation?
-Hard to develop real world tasks that will benefit the patient outside of the clinic
What is the information on pharmacological treatments?
-Compounds can facilitate plastic changes in the brain
-Can be used shortly after brain injury
-Work by reducing inflammation
What is the information on brain stimulation?
-Promising without complications