- •Both, contralateral M1 iTBS and ipsilateral M1 cTBS improved non-dominant skilled-task performance.
- •Bilateral sequential M1 TBS (contralateral cTBS followed by ipsilateral iTBS) improved skilled-task performance more than unilateral or sham TBS.
- •Bilateral sequential M1 TBS may be particularly effective in improving motor learning, also in the neurorehabilitation setting.
Posts Tagged Brain plasticity
[Abstract] Changes in transcranial magnetic stimulation outcome measures in response to upper-limb physical training in stroke: A systematic review of randomized controlled trials
Physical training is known to be an effective intervention to improve sensorimotor impairments after stroke. However, the link between brain plastic changes, assessed by transcranial magnetic stimulation (TMS), and sensorimotor recovery in response to physical training is still misunderstood. We systematically reviewed reports of randomized controlled trials (RCTs) involving the use of TMS over the primary motor cortex (M1) to probe brain plasticity after upper-limb physical training interventions in people with stroke.
We searched 5 databases for articles published up to October 2016, with additional studies identified by hand-searching. RCTs had to investigate pre/post-intervention changes in at least one TMS outcome measure. Two independent raters assessed the eligibility of potential studies and reviewed the selected articles’ quality by using 2 critical appraisal scales.
In total, 14 reports of RCTs (pooled participants = 358; mean 26 ± 12 per study) met the selection criteria. Overall, 11 studies detected plastic changes with TMS in the presence of clinical improvements after training, and these changes were more often detected in the affected hemisphere by using map area and motor evoked potential (MEP) latency outcome measures. Plastic changes mostly pointed to increased M1/corticospinal excitability and potential interhemispheric rebalancing of M1 excitability, despite sometimes controversial results among studies. Also, the strength of the review observations was affected by heterogeneous TMS methods and upper-limb interventions across studies as well as several sources of bias within the selected studies.
The current evidence encourages the use of TMS outcome measures, especially MEP latency and map area to investigate plastic changes in the brain after upper-limb physical training post-stroke. However, more studies involving rigorous and standardized TMS procedures are needed to validate these observations.
- Transcranial magnetic stimulation,
- Upper-limb physical training,
- Systematic review,
- Brain plasticity,
- Clinical outcome
Source: Elsevier: Article Locator
[Abstract] Bilateral sequential motor cortex stimulation and skilled task performance with non-dominant hand
To check whether bilateral sequential stimulation (BSS) of M1 with theta burst stimulation (TBS), using facilitatory protocol over non-dominant M1 followed by inhibitory one over dominant M1, can improve skilled task performance with non-dominant hand more than either of the unilateral stimulations do. Both, direct motor cortex (M1) facilitatory non-invasive brain stimulation (NIBS) and contralateral M1 inhibitory NIBS were shown to improve motor learning.
Forty right-handed healthy subjects were divided into 4 matched groups which received either ipsilateral facilitatory (intermittent TBS [iTBS] over non-dominant M1), contralateral inhibitory (continuous TBS [cTBS] over dominant M1), bilateral sequential (contralateral cTBS followed by ipsilateral iTBS), or placebo stimulation. Performance was evaluated by Purdue peg-board test (PPT), before (T0), immediately after (T1), and 30 min after (T2) an intervention.
In all groups and for both hands, the PPT scores increased at T1 and T2 in comparison to T0, showing clear learning effect. However, for the target non-dominant hand only, immediately after BSS (at T1) the PPT scores improved significantly more than after either of unilateral interventions or placebo.
M1 BSS TBS is an effective intervention for improving motor performance.
M1 BSS TBS seems as a promising tool for motor learning improvement with potential uses in neurorehabilitation.
We attempted a preliminary clinical trial in one active, high-quality inpatient rehabilitation facility (IRF) in the U.S. But after enrolling only four patients in the grant period, the study was stopped because of low enrollment.
The purpose of this paper is to offer a perspective describing the important physiologic rationale for including rTMS in the early phase of stroke, the reasons for our poor patient enrollment in our attempted study, and recommendations to help future studies succeed.
We conclude that, if scientists and clinicians hope to enhance stroke outcomes, more attention must be directed to leveraging conventional rehabilitation with neuromodulation in the acute phase of stroke when the capacity for neuroplasticity is optimal. Difficulties with patient enrollment must be addressed by reassessing traditional inclusion and exclusion criteria. Factors that shorten patients’ length of stay in the IRF must also be reassessed at all policy-making levels to make ethical decisions that promote higher functional outcomes while retaining cost consciousness.
The capacity for functional restitution after brain damage is quite different in the sensory and motor systems. This series of presentations highlights the potential for adaptation, plasticity, and perceptual learning from an interdisciplinary perspective. The chances for restitution in the primary visual cortex are limited. Some patterns of visual field loss and recovery after stroke are common, whereas others are impossible, which can be explained by the arrangement and plasticity of the cortical map. On the other hand, compensatory mechanisms are effective, can occur spontaneously, and can be enhanced by training. In contrast to the human visual system, the motor system is highly flexible. This is based on special relationships between perception and action and between cognition and action. In addition, the healthy adult brain can learn new functions, e.g. increasing resolution above the retinal one. The significance of these studies for rehabilitation after brain damage will be discussed.
Introduction by S. Trauzettel-Klosinski
This symposium highlighted the potential for learning and re-learning after visual and motor cortex lesions in the adult brain from an interdisciplinary perspective. We considered mechanisms such as adaptation, plasticity, and perceptual learning of different brain functions, as well as their applications for rehabilitation in patients with brain damage. Additionally, the potential for visual learning in the normal human brain was demonstrated.
In the visual system, the potential for recovery in the primary visual cortex is limited (part 1 by Jonathan Horton). Visual field defects caused by embolic stroke are constrained by the organization of the blood supply of the occipital lobe with respect to the retinotopic map. In terms of the arrangement and plasticity of the cortical map, it will be explained why some patterns of visual field loss and recovery following stroke are common, whereas others are essentially impossible. This is especially true along a visual field strip of constant width along the vertical meridian.
While the restitutive capacities of the primary visual cortex are limited, compensatory mechanisms can be very effective (part 2 by Susanne Trauzettel-Klosinski). They can occur spontaneously and can further be enhanced by training. In hemianopia, for example, fixational eye movements and scanning saccades can shift the visual field border towards the hemianopic side and improve spatial orientation and mobility.
In contrast to the visual system, the human motor system is highly flexible (part 3 by Theo Mulder). It is updated continuously by itself on the basis of sensory input and activity. The plasticity of the motor system is based on a special relationship between perception and action, as well as between cognition and action. New approaches to rehabilitation, for example by motor imagery, give an outlook on future possibilities.
Additionally, the healthy adult brain can learn new visual functions (part 4 by Manfred Fahle), for example the enhancement of resolution, which is higher than that of the retina. These functions, especially hyperacuity, can also be trained.
The authors will present a summary for each of the four talks.
Part 1: visual field recovery after lesions of the occipital lobe by Jonathan C. Horton
The answer lies in the organization of the visual pathway from eye to cortex. Retinal ganglion cell axons that are responsible for conscious perception project to the lateral geniculate nucleus. It serves as a relay station, boosting the information content of outgoing spikes compared with incoming spikes by integrating and filtering retinal signals . Geniculate neurons send their projection to layer 4 of the primary visual cortex. Simply by crossing a single synapse in the thalamus, retinal output is conveyed directly to the primary visual cortex. In a sense, the retino-geniculo-cortical pathway is the aorta of our visual system (Fig. 2). After initial processing in the primary visual cortex, signals are analyzed in surrounding cortical areas that are specialized for different attributes, allowing us to perceive the images that impinge upon our retinae.
Neuroplasticity – or brain plasticity – is the ability of the brain to modify its connections or re-wire itself. Without this ability, any brain, not just the human brain, would be unable to develop from infancy through to adulthood or recover from brain injury.
What makes the brain special is that, unlike a computer, it processes sensory and motor signals in parallel. It has many neural pathways that can replicate another’s function so that small errors in development or temporary loss of function through damage can be easily corrected by rerouting signals along a different pathway.
The problem becomes severe when errors in development are large, such as the effects of the Zika virus on brain development in the womb, or as a result of damage from a blow to the head or following a stroke. Yet, even in these examples, given the right conditions the brain can overcome adversity so that some function is recovered.
The brain’s anatomy ensures that certain areas of the brain have certain functions. This is something that is predetermined by your genes. For example, there is an area of the brain that is devoted to movement of the right arm. Damage to this part of the brain will impair movement of the right arm. But since a different part of the brain processes sensation from the arm, you can feel the arm but can’t move it. This “modular” arrangement means that a region of the brain unrelated to sensation or motor function is not able to take on a new role. In other words, neuroplasticity is not synonymous with the brain being infinitely malleable.
Part of the body’s ability to recover following damage to the brain can be explained by the damaged area of the brain getting better, but most is the result of neuroplasticity – forming new neural connections. In a study ofCaenorhabditis elegans, a type of nematode used as a model organism in research, it was found that losing the sense of touch enhanced the sense of smell. This suggests that losing one sense rewires others. It is well known that, in humans, losing one’s sight early in life can heighten other senses, especially hearing.
As in the developing infant, the key to developing new connections is environmental enrichment that relies on sensory (visual, auditory, tactile, smell) and motor stimuli. The more sensory and motor stimulation a person receives, the more likely they will be to recover from brain trauma. For example, some of the types of sensory stimulation used to treat stroke patients includes training in virtual environments, music therapy and mentally practising physical movements.
The basic structure of the brain is established before birth by your genes. But its continued development relies heavily on a process called developmental plasticity, where developmental processes change neurons and synaptic connections. In the immature brain this includes making or losing synapses, the migration of neurons through the developing brain or by the rerouting and sprouting of neurons.
There are very few places in the mature brain where new neurons are formed. The exceptions are the dentate gyrus of the hippocampus (an area involved in memory and emotions) and the sub-ventricular zone of the lateral ventricle, where new neurons are generated and then migrate through to the olfactory bulb (an area involved in processing the sense of smell). Although the formation of new neurons in this way is not considered to be an example of neuroplasticity it might contribute to the way the brain recovers from damage. …
Visit Web Site —> What Is Brain Plasticity and Why Is It So Important? | SciTech Connect
[ARTICLE] The variety of methodology in Mirror Therapy practice for improving hand function after stroke. – Full Text PDF
Many studies have shown that a repeated exercises in the mirror visual feedback and motor imagery conditions may help to restore a lasted hand function in stroke patients. The evidence of effectiveness of mirror therapy is promising but the use of this method varies widely within studies. It has been postulated that there is a need to formulate basic rules of mirror therapy application with respect to different stages of stroke or severity of hand paresis. In this article the review of methodological variability of applying mirror therapy to patients after stroke has been presented. The review highlights the benefit effect of mirror therapy on motor recovery and activities of daily living after stroke.
- What is plasticity?
How do we treat upper limb impairment?
Variability in lesion induced structure and organisation
Does Reaching a Plateau Really Happen?
Regaining a skill eleven years after my stroke made me wonder why I believed in plateaus when I was an OT. In rehab, a plateau means recovery has stopped. Here are four factors that changed my belief about recovery after a stroke.
What Has Changed.
1) Brain plasticity will blow your mind. Click here to learn how an adult’s brain grows new stem cells every night and makes them migrate to where they are needed.
2) New technology includes brain stimulation with magnets and muscle stimulation with biofeedback. To learn about NeuroMove click here.
3) People who have a stroke as young or middle-aged adults have higher expectations placed on them that people who have strokes in their 70s and 80s. Family members cannot maintain their own health if they do everything for a disabled adult for decades. Assisted living where assistance costs extra is an expensive long-term solution many families cannot afford. Necessity can drive progress.
4) Blogging allows stroke survivors to share their triumphs. I know my continued progress is not unique.
What Perpetuates the Myth.
Therapists see clients for days or weeks. This small window is suited to orthopedic cases like hip replacements because bones and muscles repair themselves fairly quickly. Brain recovery takes longer because the brain is so complex. Therapists do not see the progress stroke survivors make in the next stage of rehab (e.g. out-patient) or after therapy ends.
Using the word plateau shuts down the conversation. “Will I get better?” is an opportunity to ask if there is something a client wants to do. Here is something I wanted. I have baby-fine short hair so I need a good haircut. Before I sit down in a beauty salon chair I have to back up and then straddle the wide footrest. The chair was initially an obstacle to having a good hair day so I never get tired of defeating it. Challenges that pushed my continued recovery were walking backwards, twisting my trunk so I can reach far behind me to grab the armrest, and sitting down with my feet 18 inches apart.
The Bottom Line.
Skill acquisition can stop because of our beliefs as well as our abilities. My progress has slowed over the years, but I have repeatedly seen new goals spur new gains. This evidence has changed what I think will happen to me.
[ARTICLE] Stem Cells in the Adult Brain: Neurogenesis – Encyclopedia of Molecular Cell Biology and Molecular Medicine
The discovery that the adult mammalian brain continuously generates new neurons and glia throughout its life has altered the present view of brain plasticity and raised hope for ameliorating neurological disorders. Newborn neurons arise from neural stem cells (NSCs) located in specialized brain regions of all mammalian species, including humans. The NSCs are regulated by these specialized environments, or niches, and are subject to dynamic regulation by many physiological, pathological, and pharmacological stimuli.
Increasing evidence suggests that adult NSCs significantly contribute to specialized adaptive behavior through neural circuitry refinement. In this chapter, attention is focused on the current understanding of NSCs in the adult mammalian central nervous system, including subjects of their identity, niche, regulation, and emerging concepts on their heterogeneity and lineage relationships.