Lecture 11 - Plasticity & Recovery Flashcards
What are the symptoms after a stroke (middle cerebral artery stroke) ?
- Contralateral paralysis
- Contralateral sensory loss
- Global aphasia
- Contralateral neglect
- Cognitive problems
What are the 3 subphases of the recovery phase after a stroke ?
- Acute phase (1-7 days)
- Subacute phase : early (7 days - 3 months) & late (3 - 6 months)
- Chronic phase (>6 months)
What are the two main ways neuroplasticity occurs ?
- Change of physical structure
- Compensation of function within the existing structure
What is neuroplasticity ?
Ability of NS to reorganize its structure, function or connections
At which levels can plasticity be analyzed ?
- Behavior
- Cortical maps
- Physiology
- Synaptic organization
- Mitotic activity
- Molecular structure
What are the two general types of plasticity ?
- Experience expectant
- Experience dependent
What does plasticity correlate with ?
Behavioral changes
What is meta-plasticity ?
The interaction of plasticity with the environment
What are the dependencies of plasticity ?
- Age-dependency
- Time-dependency
- Relevance-dependency
- Intensity & frequency dependency
What are examples of plasticity at the level of cortical maps ?
- Focal hand dystonia
- Phantom limb reorganization
What are examples of plasticity at the level of physiology ?
- LT potentiation
- Kindling (seizure activity)
What is an example of plasticity at the level of synaptic organization ?
- Experience-dependent changes in dendritic arborization
What is an example of plasticity at the level of mitotic activity ?
- Continuation of neurogenesis of the olfactory bulb, hippocampus & striatum
What is an example of plasticity at the level of molecular structure ?
- Gene expression
What characterizes experience-expectant plasticity ?
- General input (visual, orientation movement..)
- Critical periods during developments
What characterizes experience-dependent plasticity ?
- Specific personal input (learning or expansion of topographical maps…)
- Modification of neuronal ensembles that are already present
What are examples of meta-plasticity ?
- Stimulant drugs & effects of complex environments
- Early life stress & effects of complex environments
What are examples of maladaptive plasticity ?
- Drugs & stress exposure
- Frontal lobe injury
- Phantom limb pain
- Focal hand dystonia
- Dementia
What constitutes “recovery” after brain injury ?
- Compensation vs functional restitution
- Recovery of lost capacity, or new way of functioning to compensate
What is an example used to illustrate compensation versus functional restitution ?
3 legged cat
What is the goal of rehabilitation after brain injury ?
- Stimulate plasticity to provide the best possible compensation
What happened after an ischemic accident ?
- Ionic changes
- Glutamate increase
- Opening calcium channels (toxic calcium levels in the cell, neuronal damage)
- mRNA : toxic production of proteins
- Inflammation, swelling
- Diaschisis
- Change in metabolism & glucose utilization
What are some prevention treatments in the acute phase of brain injury (ischemia) ?
- Block calcium channels (neuroprotectant drugs)
- Reduce inflammation (anti-inflammatory drugs)
What are the different ways of recovery after brain injury?
- Early rehabilitation : stimulating function recovery
- Late/cognitive rehabilitation : functional recovery
- Neuropsychological rehabilitation
- Injury-induced change : spontaneous recovery
- Experience-dependent change : learning
What are the three aspects of neuropsychological rehabilitation ?
- (Learning to) accept changes
- (Learning to) adapt to changes
- (Learning to) deal with changes
What are some examples of recovery after brain injury ?
- Recovery from motor-cortex damage
- Recovery from aphasia
- Recovery from traumatic lesions
- Recovery from surgical lesions
- Return to daily life
What happens when there is a blockade of the middle cerebral artery in the motor cortex ?
- Hemiplegia
- Flaccidity of muscles
- Loss of reflexive & voluntary movements
What are the stages of recovery after injury to the motor cortex ?
- Return of reflexes
- Development of rigidity
- Grasping as part of other movements
- Voluntary grasping (23-40 days after injury)
What are some common issues stroke survivors face in returning to daily life ?
- Concentration & memory problems
- Mental slowing, reduced task load (fatigue)
- Problems with emotional regulation (irritability)
- Psychological problems (anxiety/depression)
- Mourning or acceptance of lost function
What are some variables that affect recovery from brain injury ?
- Age
- Sex
- Handedness
- Premorbid IQ
- Personality
- Motivation
What are some therapeutic approaches to brain injury recovery ?
- Activity-based therapies
- Cognitive rehabilitation
- Tactile stimulation
- Brain stimulation
- Pharmacological therapies
- Cell-based therapies
- Music & other therapies
What are some examples of activity-based therapies ?
- Constraint-induces movement therapy
- Physiotherapy
- Speech therapy
What are the benefits of brain stimulation therapy in brain injury recovery ?
- rTMS : increased activity & stimulates plasticity within first month
- DBS : used for Parkinson, depression & stroke
- Vagus nerve stimulation : stimulates release of acetylcholine & norepinephrine
What is the role of pharmacological therapies in stroke recovery ?
- Prevention in acute stroke : tissue plasminogen activator (tA) & thrombectomy
- Stimulating plasticity : amphetamine, nicotine, cannabis (for smaller lesions)
- Enhance axonal sprouting : antibody to Nogo-A
- Growths factors
