Simulating a brain-cooling treatment for epilepsy

Using computer simulation techniques, scientists have gained new insights into the mechanism by which lowering the temperature of specific brain regions could potentially treat epileptic seizures. The results are published in an Oct. 5, 2017, PLOS Computational Biology article titled "Differential temperature sensitivity of synaptic and firing processes in a neural mass model of epileptic discharges explains heterogeneous response of experimental epilepsy to focal brain cooling." About 50 million people worldwide deal with sudden, recurring seizures that are the hallmark of epilepsy. Treatment with medication or surgery does not work for some patients, so scientists have been investigating a potential alternative called focal cooling, in which a device would be implanted in the brain to suppress the electrical signals – discharges – that characterize epileptic seizures. In the new study, researchers from the Nara Institute of Science and Technology in Japan sought to better understand the mechanism by which focal cooling operates. So far, the technique has been tested only temporarily in epilepsy patients as intraoperative studies, while it has shown consistent success in rats. However, focal cooling sometimes slightly increases the frequency of epileptic discharges in rats, even while suppressing their strength. To investigate how focal cooling suppresses epileptic discharges with possible increase in frequency, the research team took a computational approach. They employed a model of the rat brain that allowed them to simulate different mechanisms underlying the effects of a focal cooling device on epileptic discharges. Using data from laboratory and rat studies, the researchers first simulated a mechanism by which focal cooling reduces activity at connections between neurons, resulting in less frequent discharges. However, with this mechanism alone, the model could not accurately reproduce electrical activity patterns previously observed in focal brain cooling experiments on rats with drug-induced epilepsy. To compensate for the first mechanism, the researchers devised a second mechanism in which cooling resulted in discharges that were persistent but weaker. Incorporating both mechanisms into the model allowed the team to successfully reproduce results from previous rat experiments. Further investigation and laboratory studies could help the researchers refine their model and better understand the mechanisms that underpin focal cooling.

Transcranial direct current stimulation reduces fatigue associated with multiple sclerosis

People with multiple sclerosis (MS) who underwent a noninvasive form of electrical brain stimulation experienced significant reductions in fatigue, a common and often debilitating symptom of the disease, according to new research from the Multiple Sclerosis Comprehensive Care Center at NYU Langone Health. When compared to patients who were enrolled in a placebo arm of the study, those that received the transcranial direct current stimulation, or tDCS, were found to have about a six-point drop on a 32-point scale measuring fatigue severity, according to the findings published online Sept. 22 in the Multiple Sclerosis Journal. During tDCS, a low-amplitude, direct electrical current is applied through electrodes placed on the scalp via a headset. Because fatigue is a common complaint with MS, and with no effective treatments to address it, the researchers, encouraged by their findings, note that they may point to a future role for this technology in treating this particular symptom. In the controlled study, 27 people with MS were randomized to receive either tDCS or a placebo treatment while playing a cognitive training game that targets processing speed and working memory. They took part in 20-minute sessions, five days per week, at their homes. The participants would videoconference with a member of the study team; put their headset in place; receive a unique one-time use code to activate it; and participate in the 20-minute tDCS or placebo treatment. Fifteen patients received tDCS while 12 received the placebo. After 20 sessions, participants reported their level of fatigue using a measurement scale known as the Patient-Reported Outcomes Measurement Information System. The researchers reported a statistically significant reduction in the group that underwent tDCS compared to the placebo group, with participants on average experiencing a 5.6-point drop in fatigue while control participants actually saw a 0.9-point increase in fatigue. The article is titled "Remotely supervised transcranial direct current stimulation for the treatment of fatigue in multiple sclerosis: results from a randomized, sham-controlled trial."

Mental exercises may reduce stress

Two studies based on a nine-month investigation (called the Resource Project) report long-term mental exercises may induce exercise-specific restructuring in the brain and reduce some indicators of stress. Taken together, the findings hint that short, daily mental practices can influence changes in the brain. While recent mental training research in humans has begun to address the changes in gray matter volume (which contains most of the neuronal cells in the brain) following mindfulness or meditation exercises, most analyses focus on meditation practitioners, rather than directly assessing individuals who are new to meditation. What's more, the few longitudinal studies that have been conducted were small, lacked control groups, and were unable to examine the effects of mental practices on changes in brain function and structure within the same trainees. To investigate whether the targeted mental training of different cognitive and social skills can induce specific changes in brain morphology, a team led by Sofie Valk collected MRI data on participants between 20 and 55 years of age throughout mental training intervention. The training groups underwent three types of three-month exercise modules with weekly instructed group sessions and daily individual exercises completed via smart phone and online. The scientists found module-specific changes in cortical thickness with MRI measures, a result that correlated with individual improvements in attention, compassion and cognitive perspective-taking. A second study evaluated whether different mental training practice types were effective means for psychosocial stress reduction. After three months of training with each exercise module, Veronika Engert and colleagues examined participants' responses to the Trier Social Stress Test, a motivated performance task mimicking the type of every-day experiences that eventually accumulate to chronic stress. They assessed self-reported stress responses, as well as levels of the hormone cortisol, heart rate and markers of stress-influenced immune activity. Relative to the control group, all three practice modules reduced self-reported stress reactivity in healthy participants. However, only the training of intersubjective skills lessened the body's stress response, specifically the secretion of cortisol. Contrary to past studies, the researchers saw no effect of mental training on immune markers. The authors say their research could promote the development of mental training interventions in clinical, educational, and corporate settings, further noting that short, daily intersubjective mental practice may be a broadly accessible, low-cost approach to prevent stress-related disease and the associated financial burden to society. The data, presented in the articles "Structural plasticity of the social brain: differential change after socio-affective and cognitive mental training" and "Specific reduction in cortisol stress reactivity after social but not attention-based mental training," were published Oct. 4, 2017, in the journal Science Advances.

Nerve study shows how cells adapt to help repair damage

Genetic processes that allow cells to transform so they can mend damaged nerves have been identified by scientists. Their insights on tissue repair could advance the search for drug therapies to improve regeneration after injury, experts say. Researchers focused on injury to cells in the peripheral nervous system (PNS) – the crucial network of nerves outside the brain and spinal cord. The study, titled "Changes in the coding and non-coding transcriptome and DNA methylome that define the Schwann cell repair phenotype after nerve injury," was published Sept. 12, 2017, in the journal Cell Reports. The scientists identified molecules that potentially allow nerve-supporting cells, known as Schwann cells, to transform into a specialised version that enable them to help nerves regenerate. As well as identifying vital genes that orchestrate this transformation, the scientists discovered molecular markers that flag these Schwann cells as specialist repairers. Genes identified by the research team – led by the Universities of Edinburgh, Cambridge and University College London – were also found to be similar to those seen in tumor formation, which could shed light on cell growth in cancers. The study could inform new treatments for a set of conditions known as peripheral neuropathies, which are caused by damage to the cells in the PNS and can lead to extreme sensitivity to touch as well as numbness and muscle weakness.

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