Laboratory of Neurophysiology unveils new data on spreading depolarizations
An international paper saw light in Nature Communications.
“We conducted research in the laboratory established in 2011 with funds from the Russian Government Megagrant within the framework of a project supported by a grant from the Russian Science Foundation. The project is aimed at studying propagating depolarization – a slow wave passing through the cerebral cortex, which is characterized by a short-term burst and then a long-term suppression (depression) of the brain’s electrical activity. Such a wave occurs in various pathologic conditions, such as ischemic stroke, epilepsy, migraine, and brain injury. In migraine, it underlies the so-called visual aura, which can manifest as flickering light spots, tunnel vision, and other temporary visual distortions that precede headache attacks,” says Chief Research Associate Roustem Khazipov.
He reminds that human body cells have an electric charge, “We can say that every cell in our body, including neurons, is a battery. The voltage is 0.1 volts and is called membrane potential. All brain function is based on the membrane potential of neurons and its fluctuations. In brain ischemia, there is a loss of membrane potential because the substances necessary to maintain it (primarily oxygen) are insufficient. In conditions of oxygen deficiency neurons massively depolarize, there is a shift of the potential, which is recorded during EEG.”
The team researched spreading depolarizations and their influence on brain activity. It was found out that such waves can cause both depression and booming, contrary to previously held beliefs.
The Kazanites were responsible for studying cell changes in the brain after an ischemic stroke.
“We can say that every cell in our body, including neurons, is a battery. The voltage is 0.1 volts and is called membrane potential. All brain function is based on the membrane potential of neurons and its fluctuations. In brain ischemia, there is a loss of membrane potential because the substances necessary to maintain it (primarily oxygen) are insufficient. In conditions of oxygen deficiency neurons massively depolarize, there is a shift of the potential, which is recorded during electroencephalography,” continues Dr Khazipov.
As he explains,, new experiments on animals have shed additional light on EEG indications in brain stroke patients, “Just as in animals, a wide range of brain activity changes during depolarization waves was detected in patients. Since activity depression is one of the criteria for detecting depolarization waves in current clinical standards, the new data require revision of the widely used algorithms for depolarization wave detection. If the onset of stroke is captured and pharmacological intervention is initiated, it may be possible to firstly alleviate its course and secondly, to reduce brain tissue damage from ischemia.Early detection of propagating depolarization waves can also help to prevent migraine attacks.”
According to the neurophysiologist, it is impossible to effectively detect precursors of stroke and other pathological brain conditions using existing electroencephalographs. Therefore, KFU has created a prototype of a device that allows registering, along with the already known, new parameters of the brain’s electrical activity. Soon it will be tested on animals in the laboratories of scientific institutions in Moscow and Nizhny Novgorod.