Neuroplasticity Flashcards
is the brain a fixed structure
no
the brain’s ability to reorganize itself and form new neural connections
neural plasticity
what is the extent of plastic changes after injury due to
- spontaneous adaptation and recovery
- rehab process
- enriched environments
what is the primary mechanism of neuroplasticity
neuronal sprouting
injured neurons reconnect in new ways to remain intact neurons to maximize function of the nervous system
neuronal sprouting
how does rehab play a role in neuronal sprouting
- contributes to repair process
- protects intact neurons from degeneration due to disuse
- facilitates rewiring/reorganizing process
what are the 2 properties of neuroplasticity and describe them
- habituation: decreased response to repeated benign stimulus; decreased synaptic activity between sensory neurons, interneurons and motor neurons; negative
- reorganization: of neural circuits (cortical maps) resulting in modification of neural responses (changes in behaviors) - more efficient
what is neural plasticity dependent on
activity dependent
increase or decrease in synaptic connections through pruning and remodeling results in structural changes at the cellular level (increased dendritic arborization, dendritic spine density, number of new synapses, receptor density)
cellular plasticity
functional changes at the cellular level for plasticity
- increased/more effective excitatory postsynaptic potentials (long-term potential) and intrinsic excitability via increased levels of brain-derived neurotropic factor (BDNF)
describe neural recovery
- Restoration of brain function in tissues that were initially lost due to injury or disease
- Functional recovery
describe compensation
- Residual neural tissue takes over the functions of damaged or lost tissue
- Likely produces differences in motor ability/task performance
refers to the time during which the wiring of cortical neurons is malleable to an environment stimulus or experience
critical/sensitive periods
negative plasticity is fostered by
disuse, practice or attempts at unskilled, non-purposeful activity, reinforcement of negative behaviors, unchallenging tasks, noisy/non-specific sensory input
positive plasticity is influenced by
Intense, skilled activity practice; appropriate sensory input; novel, challenging tasks; reinforcement/reward of positive behaviors
normal aging is often characterized by physical, behavioral, and environmental changes leading to
negative plasticity
what are 4 factors that contribute to age-related functional decline
- reduced brain activity
- weakened neuromodulatory control (decreased neuromodulator)
- noisy processing (degradation of sensory organs = increased processing time)
- negative learning (takes longer to process and integrate new inputs, reduce speed and accuracy)
what measures/test can be used to measure neural plastic changes and describe what they look at
- Positron emission tomography (PET) - Images of cerebral cortex activity under certain conditions
- fMRI: Measures changes in blood flow as indirect measure of synaptic activity during select tasks
- transcranial magnetic stimulation - used extracranially to stimulate or inhibit underlying cortex; measures motor evoked potentials
what are the 10 principles of neuroplasticity and describe them
- Use it or lose it: must keep neural circuits actively engaged to prevent degradation/atrophy
- Use it and improve it (brain): creative/novel activities promote learning → brain specialization that results in enhancement of function
- Specificity matters: train for skill acquisition not just movement
- Intensity matters: low intensity stimulation = weak synaptic response → must balance high intensity and timing so as not to create further injury
- Repetition matters: large numbers of repetitive motions and progress difficulty of tasks over time
- Timing matters: brain injury evolves and resolves over time - must take advantage of critical periods of recovery
- Salience matters: activities must have meaning to the person - emotion modulates attention and motivation to recover - pts who expect to get better enhance their learning
- Age matters: plasticity occurs more rapidly in young brain, but neural adaptation can occur across lifespan
- Transference matters: plasticity is one area of the brain enhances acquisition in other areas
Interference matters: plastic changes occurring in a recovering area may interfere with new or existing functions in other parts of the system - Interference matters: plastic changes occurring in a recovering area may interfere with new or existing functions in other parts of the system
What are some of the intervention strategies a PT might use to promote neuroplasticity?
- Intensity of exercise/practice: endurance and aerobic activities are critical for recovery
- Complexity of motor tasks → more novel is better
- Must consider sensory, proprioceptive and kinesthetic inputs
- Plasticity outside of infancy is influences by reward, judgement of error, attention to task
- Sleep patterns - sleep engages strengthening of learning based plastic changes
- Brain derived neurotrophic factor (BDNF) increased with physical exercise
- Cortical stimulation - repetition transmagnetic stimulation (TMS) may enhance learning
