Research suggests SARS-CoV-2 enters the brain
In a study published Dec. 16, 2020, in Nature Neuroscience, researchers from the University of Washington found that the spike protein of the SARS-CoV-2 virus can cross the blood-brain barrier in mice. The spike protein, often called the S1 protein, dictates what cells the virus can enter. The immune system, upon seeing the virus and its proteins, overreacts in its attempt to kill the invader. “The S1 protein likely causes the brain to release cytokines and inflammatory products,” said lead author William Banks. The infected person is left with brain fog, fatigue and other cognitive issues. Banks and his team saw this reaction with the HIV virus and wanted to see if the same was happening with SARS-CoV-2. When injected intravenously, radioiodinated S1 was taken up by all 11 brain regions examined. Banks said the S1 protein in SARS-CoV-2 and the gp120 protein in HIV-1 function similarly, as they are both glycoproteins. Both proteins function as the arms and hand for their viruses by grabbing onto other receptors. Previous research has showed gp120 is able to cross the blood-brain barrier and is toxic to brain tissues. The recent study could explain many of the complications from COVID-19.
Technique developed to predict seizures
Researchers from Switzerland have succeeded in developing a technique that can predict seizures between one and several days in advance by recording neuronal activity with electroencephalography over at least six months. The team obtained neuronal activity data collected over several years using devices implanted long-term in the brains of patients with epilepsy. After confirming that there were indeed cycles of cerebral epileptic activity, the researchers turned their attention to statistical analysis. This approach, published Dec. 17, 2020, in Lancet Neurology, helped highlight a phenomenon known as the pro-ictal state, in which the probability of the onset of a seizure is high. The researchers now are working to develop a minimally invasive brain monitoring device to record the long-term data needed to forecast seizures. The device, which slips under the skin of the scalp, could give people with epilepsy the power to plan their lives according to the likelihood of having a seizure.
Machine intelligence improves brain mapping research
Scientists in Japan’s Brain Mapping by Integrated Neurotechnologies for Disease Studies program have used machine intelligence to improve the accuracy and reliability of a magnetic resonance imaging (MRI)-based technique, according a study published Dec. 18, 2020, in Scientific Reports. Diffusion MRI-based fiber tracking uses magnetic fields to track signals from water molecules as they diffuse along nerve fibers in order to estimate connectomes noninvasively. A computer algorithm then uses these water signals to estimate the path of the nerve fibers throughout the whole brain. At present, the algorithms do not produce convincing results. Furthermore, the algorithms struggle to detect nerve fibers that stretch between remote regions of the brain. In the current study, the researchers set out to fine-tune the parameters of two different widely used algorithms. They used an evolutionary algorithm, which estimated the connectome from the diffusion MRI data using parameters that changed in each successive generation. Those parameters competed against each other and the best parameters; the ones that generated connectomes that most closely matched the neural network detected by the fluorescent tracer advanced to the next generation. The researchers tested the algorithms using fluorescent tracer and MRI data from 10 different marmoset brains. At the end of the process, the researchers took the best parameters and averaged them to create one shared set. The team found that the algorithm with the generic set of optimized parameters also generated a more accurate connectome in new marmoset brains that weren’t part of the original training set, compared with the default parameters used previously.
Hearing, blood sugar linked to cognitive function among older Latinos
In a study published Dec. 17, 2020, in the online issue of JAMA Otolaryngology-Head & Neck Surgery, researchers led by the University of California San Diego School of Medicine reported that hearing loss and high blood sugar are associated with poor cognitive performance among middle-aged and older Latinos. As part of the Hispanic Community Health Study/Study of Latinos, more than 9,000 Latinos (ages 45 to 74 years) underwent hearing examinations, extensive cardiovascular and diabetes testing and cognitive assessments. Those who displayed hearing loss also included individuals with mild to severe levels of cognitive impairment. “Initially, we thought that the relationships between hearing loss and cognition would be overshadowed by high cardiovascular disease risk, but this was not the case,” said first author Ariana Stickel. “This [research] opens up promising avenues for interventions to reduce Alzheimer’s disease risk.”