Posts Tagged brain connectivity
[ARTICLE] Novel gait training alters functional brain connectivity during walking in chronic stroke patients: a randomized controlled pilot trial – Full Text
Posted by Kostas Pantremenos in Gait Rehabilitation - Foot Drop on March 18, 2019
Abstract
Background
A recent study has demonstrated that a turning-based treadmill program yields greater improvements in gait speed and temporal symmetry than regular treadmill training in chronic stroke patients. However, it remains unknown how this novel and challenging gait training shapes the cortico-cortical network and cortico-spinal network during walking in chronic stroke patients. The purpose of this study was to examine how a novel type of gait training, which is an unfamiliar but effective task for people with chronic stroke, enhances brain reorganization.
Methods
Subjects in the experimental and control groups received 30 min of turning-based treadmill training and regular treadmill training, respectively. Cortico-cortical connectivity and cortico-muscular connectivity during walking and gait performance were assessed before and after completing the 12-session training.
Results
Eighteen subjects (n = 9 per group) with a mean age of 52.5 ± 9.7 years and an overground walking speed of 0.61 ± 0.26 m/s consented and participated in this study. There were significant group by time interactions for gait speed, temporal gait symmetry, and cortico-cortical connectivity as well as cortico-muscular connectivity in walk-related frequency (24–40 Hz) over the frontal-central-parietal areas. Compared with the regular treadmill training, the turning-based treadmill training resulted in greater improvements in these measures. Moreover, the increases in cortico-cortical connectivity and cortico-muscular connectivity while walking were associated with improvements in temporal gait symmetry.
Conclusions
Our findings suggest this novel turning-based treadmill training is effective for enhancing brain functional reorganization underlying cortico-cortical and corticomuscular mechanisms and thus may result in gait improvement in people with chronic stroke.
Introduction
A recent study suggested that chronic stroke patients maintain the capacity to increase synchronization of neural activity between different brain regions as measured by EEG connectivity. These changes of functional connectivity in the motor cortex through neurofeedback correlate with improvements in motor performance [1]. Previously, we demonstrated that a novel specific training, the turning-based treadmill program, yielded greater improvements in gait speed and temporal symmetry than regular treadmill training for people with chronic stroke [2]. We presumed the turning-based treadmill training, which is a challenging and unfamiliar training task for chronic stroke patients, may facilitate brain reorganization and behavioral recovery [3]. Thus, we sought to understand how such novel gait training promotes brain reorganization in this study.
An EEG-based method has the advantage of real-time recording during walking due to the relative ease of data acquisition. As indicated by the authors of the first study to use an EEG signal recorded during walking, the power increases within numerous frequency bands (3–150 Hz) in the sensorimotor cortex and is more pronounced during the end of the stance phase of walking [4]. Source localization EEG analysis revealed the importance of the primary somatosensory, somatosensory association, primary motor and cingulate cortex in gait control [5]. Focal lesions due to stroke may not only affect the functional connectivity of cortical areas [6] but also impede the neural transmission of descending motor pathways [7]. Based on spectral analysis, the direct relationship of cortical activities with peripheral movements is still unknown. Accordingly, an analysis of EEG-EMG coherence recorded during treadmill walking was done by Petersen et al. [8], who demonstrated that cortical activity in the primary motor cortex within the gamma band (24–40 Hz) was transmitted via the corticospinal tract to the leg muscles during the swing phase of walking. In addition, a recent study confirmed the strong correlation between kinematic errors of the lower extremities and fronto-centroparietal connectivity during gait training and post-training in healthy subjects [9]. However, it remains unknown how novel and challenging gait training shapes the cortico-cortical network and cortico-spinal network during walking in individuals with chronic stroke. Therefore, the aims of the current study were to explore the effects of the turning-based treadmill training, a novel gait training program, on cortico-cortical connectivity and corticomuscular connectivity and to investigate the relationship between connectivity changes and gait performance in chronic stroke patients.[…]
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[WEB SITE] OCD: Cognitive behavioral therapy improves brain connectivity
Posted by Kostas Pantremenos in Cognitive Rehabilitation on September 25, 2017
MRI scans show that people diagnosed with OCD who have undergone CBT have intensified connectivity between key brain networks.
Obsessive-compulsive disorder (OCD) is a condition marked by inescapable, intrusive thoughts that cause anxiety (hence “obsessive”), and repetitive, ritualistic behaviors aimed at reducing that feeling (hence “compulsive”).
OCD can be a debilitating condition and can severely impair daily functioning. The National Institutes of Mental Health estimate that, in the United States, the yearly prevalence of OCD amounts to 1 percent of the total adult population. Around half of these cases are deemed “severe.”
Treatments for OCD include the administration of selective serotonin reuptake inhibitors and cognitive behavioral therapy (CBT), a type of therapy that aims to improve damaging mind associations.
Researchers from the University of California, Los Angeles – who were led by Dr. Jamie Feusner – have conducted a study aiming to find out whether and how CBT might change levels of activity and network connectivity in the brains of people diagnosed with OCD.
They explain that although the efficacy of CBT in treating OCD has been previously explored, this is likely the first study to use functional MRI (fMRI) to monitor what actually happens in the brains of people with OCD after exposure to this kind of therapy.
The researchers’ findings were recently published in the journal Translational Psychiatry.
Changes in key brain regions following CBT
The team specifically targeted the effects of exposure and response prevention (ERP)-based CBT, which entails exposure to triggering stimuli and encouraging the individual to wilfully resist responding to those stimuli in the way that they normally would.
For the study, 43 people with OCD and 24 people without it were recruited. The results for the two groups were later compared, at which point the 24 individuals without OCD were taken as the control group.
All the participants diagnosed with OCD received intensive ERP-based CBT on an individual basis in 90-minute sessions on 5 days per week, for a total of 4 weeks.
Participants from both groups underwent fMRI. Those diagnosed with OCD, who had received CBT, were scanned both before the treatment period and after the 4 weeks of treatment. Participants from the control group, who did not undergo CBT, also had fMRI scans after 4 weeks.
When the scans of participants with OCD were compared, the results from before exposure to CBT and after it were found to be largely contrasting.
The researchers noticed that the brains of people with OCD exhibited a significant increase in connectivity between eight different brain networks, including the cerebellum, the caudate nucleus and putamen, and the dorsolateral and ventrolateral prefrontal cortices.
The dorsolateral and ventrolateral prefrontal cortices are involved with planning action and movement, as well as regulating certain cognitive processes.
Dr. Feusner and team point out that an increased level of connectivity between these cerebral regions suggests that the brains of the people who underwent CBT were “learning” new non-compulsive behaviors and activating different thought patterns.
He suggests that these changes may be novel ways of coping with the cognitive and behavioral idiosyncrasies of OCD.
“The changes appeared to compensate for, rather than correct, underlying brain dysfunction. The findings open the door for future research, new treatment targets, and new approaches.”
Dr. Jamie Feusner
First study author Dr. Teena Moody adds that being able to show that there are quantifiable positive changes in the brain following CBT may give people diagnosed with OCD more confidence in following suitable treatments.
“The results could give hope and encouragement to OCD patients,” says Dr. Moody, “showing them that CBT results in measurable changes in the brain that correlate with reduced symptoms.”
Source: OCD: Cognitive behavioral therapy improves brain connectivity
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[WEB SITE] Brain Connectivity Study Could Lead to Better Outcomes for Epilepsy Patients – Health News
Posted by Kostas Pantremenos in Epilepsy on May 28, 2015
The areas in purple are the regions of the brain where connectivity is significantly lower in patients with epilepsy, as compared to well patients.
The different images show the brain data from different angles. Image courtesy of Dario Englot
A new study found that patients with epilepsy have significantly weaker connections throughout their brain, particularly in regions important for attention and cognition, compared to individuals without epilepsy.
These weaker brain connections may reflect harmful long-term effects of recurrent seizures, but importantly the connectivity patterns may be used in the future to help locate which part of the brain is causing seizures, and may help doctors plan more effective surgeries.
In the study, 61 epilepsy patients and 31 controls subjects were analyzed using a non-invasive whole-brain imaging technique that detects magnetic fields produced by the electrical signals in the brain. The technique is called magnetoencephalography, and these MEG signals are used to examine the strength of connections in the brain.
Neurosurgery reisident Dario Englot, MD, PhD, sought to learn what the patterns of brain connectivity in epilepsy patients may tell us about the long-term effects of seizures on the brain. The findings suggest these connectivity patterns could help predict which individuals might benefit most from epilepsy surgery.
Intervening Earlier to Protect the Brain
The researchers found that patients who have had epilepsy for a longer period of time or have more frequent seizures had the most abnormal brain connectivity, suggesting that seizures may have progressive negative effects on the brain over time. This might advocate for early aggressive treatment of epilepsy that is not controlled with medication, to prevent these damaging effects of seizures that accumulate over time.
All patients in the study had seizures that were not controlled despite several anti-epileptic medications, and all ultimately underwent brain surgery to remove the part of the brain causing the seizures. After surgery, about two-thirds of patients became seizure-free. The investigators then examined whether brain connectivity patterns could predict which patients stopped having seizures after surgery.
More Precise Surgeries
Interestingly, those patients who became seizure-free were more likely to have an area of increased connectivity in the part of the brain causing seizures. This was not often seen in individuals who continued to have seizures after surgery. This suggests that although the brain is less connected overall in epilepsy patients, the part of the brain causing seizures may actually have increased connectivity.
Knowing this, MEG studies of brain connectivity could help determine which part of the brain is causing seizures, and may help predict a patient’s chance of becoming seizure-free after epilepsy surgery.
The study, published in the journal Brain, is the product off a multidisciplinary effort at the University of California, San Francisco, including biomedical engineer Srikantan Nagarajan, PhD, neurologist Heidi Kirsch, MD, neurosurgeon Edward Chang, M.D., and several other investigators.
University of California
via Health News – Brain Connectivity Study Could Lead to Better Outcomes for Epilepsy Patients.
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