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These were the top neuroscience stories for the week of October 12, 2020.
The Brain Cells That Help You Quench Your Thirst
After a long, sweaty workout you may reach for a sports drink instead of plain water. You need to rehydrate but your body also craves the salts lost during exertion. Distinct groups of neurons in the brain give rise to this unique kind of thirst, researchers reported October 14 in Nature. They simulated different types of thirst in mice — by depleting fluids or depleting fluids plus salts — and examined how neurons in the mice’s brains responded. They focused on a brain region involved in thirst called the lamina terminalis — a thin sheet of neurons lining one of the fluid-filled ventricles. The two types of thirst activated distinct clusters of neurons in this region. To confirm these two groups of cells were driving different thirst behaviors, they conducted a second experiment where they activated neurons using a technique called optogenetics. When they activated the salt-sensing cells, the mice lapped up salty water. But when they activated the water-only thirst cells, the mice opted for plain water.
Related: Feeling Thirsty?
Read more: Water or A Sports Drink? These Brain Cells May Decide Which One We Crave (NPR)
COVID-19 May Cause Sudden Hearing Loss
COVID-19 may cause sudden — and possibly permanent — hearing loss, researchers reported October 13 in BMJ Case Reports. They described the case of a 45-year-old man in the U.K. who developed tinnitus and sudden hearing loss in one ear a week after being released from the hospital for COVID-19 treatment. Though they couldn’t determine a precise cause, they think it was related to infection with the novel coronavirus or the treatment he received for recovery. Steroids partially restored his hearing.
Big picture: More than 10 months into the pandemic, there is ample evidence that COVID-19 can affect the nervous system: a sudden loss of smell or taste is a telltale sign of infection and many patients experience cognitive problems, headaches, seizures, and strokes. Scientists are still trying to figure out if theses neurological symptoms result from inflammation or direct infection of nerve cells.
Read more: Covid may cause sudden, permanent hearing loss – UK study (The Guardian)