Archive for category Neuroplasticity
- It is by now well established that exercise has positive effects on the brain, especially as we age.
- Less clear has been why physical activity affects the brain in the first place.
- Key events in the evolutionary history of humans may have forged the link between exercise and brain function.
- Cognitively challenging exercise may benefit the brain more than physical activity that makes fewer cognitive demands.
In the 1990s researchers announced a series of discoveries that would upend a bedrock tenet of neuroscience. For decades the mature brain was understood to be incapable of growing new neurons. Once an individual reached adulthood, the thinking went, the brain began losing neurons rather than gaining them. But evidence was building that the adult brain could, in fact, generate new neurons. In one particularly striking experiment with mice, scientists found that simply running on a wheel led to the birth of new neurons in the hippocampus, a brain structure that is associated with memory. Since then, other studies have established that exercise also has positive effects on the brains of humans, especially as we age, and that it may even help reduce the risk of Alzheimer’s disease and other neurodegenerative conditions. But the research raised a key question: Why does exercise affect the brain at all?
Physical activity improves the function of many organ systems in the body, but the effects are usually linked to better athletic performance. For example, when you walk or run, your muscles demand more oxygen, and over time your cardiovascular system responds by increasing the size of the heart and building new blood vessels. The cardiovascular changes are primarily a response to the physical challenges of exercise, which can enhance endurance. But what challenge elicits a response from the brain?
Answering this question requires that we rethink our views of exercise. People often consider walking and running to be activities that the body is able to perform on autopilot. But research carried out over the past decade by us and others would indicate that this folk wisdom is wrong. Instead exercise seems to be as much a cognitive activity as a physical one. In fact, this link between physical activity and brain health may trace back millions of years to the origin of hallmark traits of humankind. If we can better understand why and how exercise engages the brain, perhaps we can leverage the relevant physiological pathways to design novel exercise routines that will boost people’s cognition as they age—work that we have begun to undertake.
FLEXING THE BRAIN
To explore why exercise benefits the brain, we need to first consider which aspects of brain structure and cognition seem most responsive to it. When researchers at the Salk Institute for Biological Studies in La Jolla, Calif., led by Fred Gage and Henriette Van Praag, showed in the 1990s that running increased the birth of new hippocampal neurons in mice, they noted that this process appeared to be tied to the production of a protein called brain-derived neurotrophic factor (BDNF). BDNF is produced throughout the body and in the brain, and it promotes both the growth and the survival of nascent neurons. The Salk group and others went on to demonstrate that exercise-induced neurogenesis is associated with improved performance on memory-related tasks in rodents. The results of these studies were striking because atrophy of the hippocampus is widely linked to memory difficulties during healthy human aging and occurs to a greater extent in individuals with neurodegenerative diseases such as Alzheimer’s. The findings in rodents provided an initial glimpse of how exercise could counter this decline.
Following up on this work in animals, researchers carried out a series of investigations that determined that in humans, just like in rodents, aerobic exercise leads to the production of BDNF and augments the structure—that is, the size and connectivity—of key areas of the brain, including the hippocampus. In a randomized trial conducted at the University of Illinois at Urbana-Champaign by Kirk Erickson and Arthur Kramer, 12 months of aerobic exercise led to an increase in BDNF levels, an increase in the size of the hippocampus and improvements in memory in older adults.
Other investigators have found associations between exercise and the hippocampus in a variety of observational studies. In our own study of more than 7,000 middle-aged to older adults in the U.K., published in 2019 in Brain Imaging and Behavior, we demonstrated that people who spent more time engaged in moderate to vigorous physical activity had larger hippocampal volumes. Although it is not yet possible to say whether these effects in humans are related to neurogenesis or other forms of brain plasticity, such as increasing connections among existing neurons, together the results clearly indicate that exercise can benefit the brain’s hippocampus and its cognitive functions.
Researchers have also documented clear links between aerobic exercise and benefits to other parts of the brain, including expansion of the prefrontal cortex, which sits just behind the forehead. Such augmentation of this region has been tied to sharper executive cognitive functions, which involve aspects of planning, decision-making and multitasking—abilities that, like memory, tend to decline with healthy aging and are further degraded in the presence of Alzheimer’s. Scientists suspect that increased connections between existing neurons, rather than the birth of new neurons, are responsible for the beneficial effects of exercise on the prefrontal cortex and other brain regions outside the hippocampus.
UPRIGHT AND ACTIVE
With mounting evidence that aerobic exercise can boost brain health, especially in older adults, the next step was to figure out exactly what cognitive challenges physical activity poses that trigger this adaptive response. We began to think that examining the evolutionary relation between the brain and the body might be a good place to start. Hominins (the group that includes modern humans and our close extinct relatives) split from the lineage leading to our closest living relatives, chimpanzees and bonobos, between six million and seven million years ago. In that time, hominins evolved a number of anatomical and behavioral adaptations that distinguish us from other primates. We think two of these evolutionary changes in particular bound exercise to brain function in ways that people can make use of today.
For more, visit —-> Why Your Brain Needs Exercise – Scientific American
The human brain is a wonderful organ with amazing flexibility. Learn more about recovery.
[Abstract] Music Therapy Enhances Executive Functions and Prefrontal Structural Neuroplasticity after Traumatic Brain Injury: Evidence from a Randomized Controlled Trial
Traumatic brain injury (TBI) causes lifelong cognitive deficits, particularly impairments of executive functioning (EF). Musical training and music-based rehabilitation have been shown to enhance cognitive functioning and neuroplasticity, but the potential rehabilitative effects of music in TBI are still largely unknown. The aim of the present crossover randomized controlled trial (RCT) was to determine the clinical efficacy of music therapy on cognitive functioning in TBI and to explore its neural basis.
Using an AB/BA design, 40 patients with moderate or severe TBI were randomized to receive a 3-month neurological music therapy intervention either during the first (AB, n = 20) or second (BA, n = 20) half of a 6-month follow-up period. Neuropsychological and motor testing and magnetic resonance imaging (MRI) were performed at baseline and at the 3-month and 6-month stage. Thirty-nine subjects who participated in baseline measurement were included in an intention-to-treat analysis using multiple imputation. Results showed that general EF (as indicated by the Frontal Assessment Battery [FAB]) and set shifting improved more in the AB group than in the BA group over the first 3-month period and the effect on general EF was maintained in the 6-month follow-up. Voxel-based morphometry (VBM) analysis of the structural MRI data indicated that gray matter volume (GMV) in the right inferior frontal gyrus (IFG) increased significantly in both groups during the intervention versus control period, which also correlated with cognitive improvement in set shifting. These findings suggest that neurological music therapy enhances EF and induces fine-grained neuroanatomical changes in prefrontal areas.
The Vagus Nerve Stimulation (VNS) may promote reorganization of motor networks via engaging a variety of molecular and neuronal mechanisms through ascending neuromodulatory systems. A recently published review from Frontiers in Neuroscience (N.D. Engineer et al. Targeted Vagus nerve stimulation for rehabilitation after stroke, Front Neurosci. 2019, 29;13:280) has laid out how recent experimental and clinical studies are providing increasing evidence for a beneficial effect of vagus nerve stimulation for the motor recovery after stroke of both, ischemic and hemorrhagic origin. Two multi-site, randomized controlled pilot trials have suggested that when paired with neurorehabilitation, VNS stimulation may generate temporally precise neuromodulatory feedback within the synaptic eligibility trace and may hence, drive synaptic plasticity.
- A single-blinded, randomized feasibility study evaluating VNS paired with motor rehabilitation was performed by Dawson et al. (2016) in 20 participants > 6 months after ischemic stroke who had moderate to severe upper limb weakness. Subjects were randomized to VNS paired with rehabilitation (n = 9; implanted) or rehabilitation alone (n = 11; not implanted). VNS was triggered by a physiotherapist pushing a button during task-specific movements. The main outcome measures were a change in upper extremity Fugl-Meyer Assessment (FMAUE) score and response rate – FMA-UE change _6 points was considered clinically meaningful. After 6 weeks of in-clinic rehabilitation, participants in the paired VNS group showed a 9.6-point improvement from baseline while the control group improved by 3 points in the per-protocol analysis (between group difference = 6.5 points, CI: 0.4 to 12.6, p = 0.038). The response rates were 66 and 36.4% in VNS and control groups, respectively. No serious adverse device effects were reported.
- The second study was a multicenter, fully blinded and randomized study (Kimberley et al., 2018). All participants were implanted with the VNS device, which allowed the control group to crossover to receive paired VNS therapy after completion of blinded follow-up. This permitted a within subject comparison of gains. To evaluate the lasting effects of VNS stimulation combined with home-based physiotherapy was included as part of the study. Seventeen participants who had moderate to severe upper extremity impairment after stroke were enrolled at four sites. Both groups had 1 month of at-home exercises with no VNS followed by 2 months of home-based therapy. During home therapy, participants in both groups activated the VNS device at the start of each 30-min session via a magnetswipe over the implanted pulse generator to deliver either Active or Paired VNS (0.8 mA) or Control VNS (0 mA), respectively. After 2 months of home-based therapy, thepaired VNS group continued the VNS therapy while the Control Group switched over to receive paired VNS. After 6 weeks of in-clinic therapy, the FMA-UE score increased by 7.6 points for the VNS group and 5.3 points for controls. Three months after the end of in-clinic therapy (post-90), the FMA-UE increased by 9.5 in the paired VNS group and 3.8 points in controls. At post-90, response rate (FMA-UE change _6 points) was 88% in the VNS group and 33% in controls (p = 0.03).
Noteworthy in both studies seemed the greater improvement of the upper limb function when physiotherapy was applied simultaneously with vagal nerve stimulation. VNS likely supported the recovery of upper limb functions via activation of multiple neuromodulatory networks that regulate synaptic plasticity. This may include the noradrenergic, cholinergic, and serotonergic systems (Nichols et al., 2011; Hulsey et al., 2017). These neuromodulators, in turn, act synergistically to alter spike-timing dependent plasticity (STDP) properties in active networks. The studies above align well with the time scale of the synaptic eligibility trace. VNS may drive temporally precise neuromodulatory release to reinforce ongoing neural activity related to the therapeutic event. An open question is whether similar improvement can be achieved using non-invasive vagal nerve stimulation. To this moment, the identifying and consistently delivering stimulation within a particular range of parameters appears to be of greater challenge with non-invasive VNS than with the implanted VNS device.
Physiotherapy combined with vagal nerve stimulation seems to be a new and promising approach to enhance the functional recovery after stroke.
- Vagus Nerve Stimulation (VNS) may promote reorganization of motor networks
- Experimental and clinical studies pointed towards a beneficial effect for the motor recovery after stroke
- VNS may drive temporally precise neuromodulatory release to reinforce ongoing neural activity
Targeted Vagus Nerve Stimulation for Rehabilitation After Stroke. https://www.ncbi.nlm.nih.gov/pubmed/30983963
In the present work, we investigated the relationship of oscillatory sensorimotor brain activity to motor recovery. The neurophysiological data of 30 chronic stroke patients with severe upper‐limb paralysis are the basis of the observational study presented here. These patients underwent an intervention including movement training based on combined brain–machine interfaces and physiotherapy of several weeks recorded in a double‐blinded randomized clinical trial. We analyzed the alpha oscillations over the motor cortex of 22 of these patients employing multilevel linear predictive modeling. We identified a significant correlation between the evolution of the alpha desynchronization during rehabilitative intervention and clinical improvement. Moreover, we observed that the initial alpha desynchronization conditions its modulation during intervention: Patients showing a strong alpha desynchronization at the beginning of the training improved if they increased their alpha desynchronization. Patients showing a small alpha desynchronization at initial training stages improved if they decreased it further on both hemispheres. In all patients, a progressive shift of desynchronization toward the ipsilesional hemisphere correlates significantly with clinical improvement regardless of lesion location. The results indicate that initial alpha desynchronization might be key for stratification of patients undergoing BMI interventions and that its interhemispheric balance plays an important role in motor recovery.
Stroke is a major global health problem. The number of stroke victims has been rising in the past years all around the world. Millions of stroke survivors are left with very limited motor function or complete paralysis and depend on assistance (Feigin et al., 2016). Therapeutic approaches such as constraint‐induced movement therapy are not applicable to the group of patients with severe limb weakness (Birbaumer, Ramos‐Murguialday, & Cohen, 2008). However, brain–machine interface (BMI) training has demonstrated efficacy in promoting motor recovery in chronic paralyzed stroke patients (Ramos‐Murguialday et al., 2013), and long term effects (Ramos‐Murguialday et al., 2019). Subsequent work has replicated and confirmed BMI efficacy. Arm and hand movements are trained using a body actuator (e.g., orthotic robots) that is controlled by oscillatory activity of the brain (Ang et al., 2014; Frolov et al., 2017; Kim, Kim, & Lee, 2016; Leeb et al., 2016; Mokienko et al., 2016; Ono et al., 2014). Brain signals can thus travel to the limb muscles along an alternative pathway. Contingently linking movement‐related patterns of brain activity and visuo‐proprioceptive feedback of the movement supports associative learning (Ramos‐Murguialday et al., 2012; Sirigu et al., 1995).
Changes in sensorimotor brain oscillations involved in planning and execution of movements were used as control signals for the BMI in the aforementioned studies. The sensorimotor rhythm (SMR) is an oscillation within the alpha frequency range of the EEG during a motionless resting state over the central‐parietal brain regions. Movement planning, imagination and execution lead to its suppression. In the present work, we investigate EEG brain oscillations of the alpha frequency, ranging from 8 to 12 Hz, over the motor cortex, and we term them “alpha oscillations.”
Biomarkers could be defined as indicators “of disease state that can be used as a measure of underlying molecular/cellular processes that may be difficult to measure directly in humans” (Boyd et al., 2017). When dealing with a condition as heterogeneous as stroke validated biomarkers of recovery could help plan treatments and support efficient allocation of resource while maximizing outcome for the patients. Alpha brain oscillations have been evaluated as markers of ischaemia and predictors of clinical outcome in acute patients (Finnigan & van Putten, 2013; Rabiller, He, Nishijima, Wong, & Liu, 2015). Desynchronization in the alpha frequency range has also been investigated as a marker of stroke and a predictor of recovery in the same patient group. Tangwiriyasakul, Verhagen, Rutten, and Putten (2014) showed that the recovery of motor function was accompanied by an increase of alpha desynchronization on the ipsilesional side. In subacute patients presenting mild to moderate motor deficits recovery lead to a similar increase of alpha desynchronization on the affected hemisphere (Platz, Kim, Engel, Kieselbach, & Mauritz, 2002). Furthermore, first attempts investigated correlations of alpha desynchronization with motor improvements in chronically impaired patients (Kaiser et al., 2012). In a controlled study, a group of subacute patients with severe deficits used motor imagery, guided by a brain–computer interface, in addition to their regular physiotherapeutic rehabilitation protocol. They showed a higher probability for motor improvements with increased alpha desynchronization (Pichiorri et al., 2015).
In the present work, we investigated what changes in the oscillatory activity of the brain a proprioceptive BMI coupled with physiotherapy produces over the course of a training intervention and if these correlate with recovery in severely paralyzed chronic stroke patients. We hypothesized that functional motor improvements are accompanied by an ipsilesional increase and a contralesional decrease in alpha desynchronization indicating reorganization of compensatory brain activity from the contralesional to the ipsilesional hemisphere. We intend to establish alpha oscillatory activity as a biomarker of motor impairment and as a building block of statistical models of stroke neurorehabilitation.[…]
Neuroplasticity is the brain’s ability to restructure its neural connections at any given moment. It allows nerve cells to adjust their formation in response to novelty and challenged.
This video talks about the key principles of neuroplasticity and the 6 simple ways to increase neuroplasticity.
Read the article for the studies: http://siimland.com/how-to-increase-n…
Brain Training Playlist: https://www.youtube.com/watch?v=r0168…
Table of Contents What is Neuroplasticity: 00:14 Neuroplasticity Explained: 00:49 Benefits of Neuroplasticity: 01:54 The Key to Increase Neuroplasticity: 02:22 Strategies to Increase Neuroplasticity: 02:32 #1 Whole-Brain Holistic Thinking: 02:40 #2 Practice FLOW: 04:08 #3 Expose Yourself to Novelty: 05:25 #4 Meditation: 05:45 #5 Exercise: 06:20 #6 Intermittent Fasting: 06:43 Nutrients for Neuroplasticity: 07:04 Concluding Remarks: 08:12 Become Limitless: 08:52
What if your brain at 77 were as plastic as it was at 7? What if you could learn Mandarin with the ease of a toddler or play Rachmaninoff without breaking a sweat? A growing understanding of neuroplasticity suggests these fantasies could one day become reality. Neuroplasticity may also be the key to solving diseases like Alzheimer’s, depression, and autism. In this program, leading neuroscientists discuss their most recent findings and both the tantalizing possibilities and pitfalls for our future cognitive selves.
PARTICIPANTS: Alvaro Pascual-Leone, Nim Tottenham, Carla Shatz
MODERATOR: Guy McKhann
MORE INFO ABOUT THE PROGRAM AND PARTICIPANTS: https://www.worldsciencefestival.com/…
This program is part of the BIG IDEAS SERIES, made possible with support from the JOHN TEMPLETON FOUNDATION.
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TOPICS: – Opening film 00:07 – What is neuroplasticity? 03:53 – Participant introductions 04:21 – Structure of the brain 05:21 – Is the brain fundamentally unwired at the start? 07:02 – Why does the process of human brain development seem inefficient? 08:30 – Balancing stability and plasticity 10:43 – Critical periods of brain development 13:01 – Extended human childhood development compared to other animals 14:54 – Stability and. plasticity in the visual system 17:37 – Reopening the visual system 25:13 – Pros and cons of brain plasticity vs. stability 27:28 – Plasticity in the autistic brain 29:55 – What is Transcranial magnetic stimulation (TMS) 31:25 – Phases of emotional development 33:10 – Schizophrenia and plasticity 37:40 – Recovery from brain injury 40:24 – Modern rehabilitation techniques 47:21 – Holy grail of Neuroscience 50:12 – Enhancing memory performance as we age 53:37 – Regulating emotions 57:19
PROGRAM CREDITS: – Produced by Nils Kongshaug – Associate Produced by Christine Driscoll – Opening film written / produced by Vin Liota – Music provided by APM – Additional images and footage provided by: Getty Images, Shutterstock, Videoblocks
This program was recorded live at the 2018 World Science Festival and has been edited and condensed for YouTube.
Through treating everything from strokes to car accident traumas, neurosurgeon Jocelyne Bloch knows the brain’s inability to repair itself all too well. But now, she suggests, she and her colleagues may have found the key to neural repair: Doublecortin-positive cells. Similar to stem cells, they are extremely adaptable and, when extracted from a brain, cultured and then re-injected in a lesioned area of the same brain, they can help repair and rebuild it. “With a little help,” Bloch says, “the brain may be able to help itself.”
What is Neuroplasticity? Dr. Matthew Antonucci from Plasticity Brain Centers of Orlando, Florida gives us a breakdown of what the term really means.