Summary: Exposure to anesthesia causes lipid clusters to move from an ordered state to a disordered one, then back again. These changes lead to subsequent effects that cause changes in consciousness.

Source: Scripps Research Institute

Surgery would be inconceivable without general anesthesia, so it may come as a surprise that despite its 175-year history of medical use, doctors and scientists have been unable to explain how anesthetics temporarily render patients unconscious.

In addition, the mice developed interstitial pneumonia, which affects the tissue and space around the air sacs of the lungs, causing the infiltration of inflammatory cells, the thickening of the structure that separates air sacs, and blood vessel damage. Compared with young mice, older mice showed more severe lung damage and increased production of signaling molecules called cytokines. Taken together, these features recapitulate those observed in COVID-19 patients.

When the researchers administered SARS-CoV-2 into the stomach, two of the three mice showed high levels of viral RNA in the trachea and lung. The S protein was also present in lung tissue, which showed signs of inflammation. According to the authors, these findings are consistent with the observation that patients with COVID-19 sometimes experience gastrointestinal symptoms such as diarrhea, abdominal pain, and vomiting. But 10 times the dose of SARS-CoV-2 was required to establish infection through the stomach than through the nose.

Future studies using this mouse model may shed light on how SARS-CoV-2 invades the brain and how the virus survives the gastrointestinal environment and invades the respiratory tract. “The hACE2 mice described in our manuscript provide a small animal model for understanding unexpected clinical manifestations of SARS-CoV-2 infection in humans,” concluded co-senior study author Chang-Fa Fan of NIFDC. “This model will also be valuable for testing vaccines and therapeutics to combat SARS-CoV-2.”

Subtle patterns can be seen in people’s reaction times as their memories are recalled, and boosting these brainwaves could help treat Alzheimer’s disease.

Although we often think of knowledge as “knowing that” (for example, knowing that Paris is the capital of France), each of us also knows many procedures consisting of “knowing how,” such as knowing how to tie a knot or start a car. Now, a new study has found the brain programs that code the sequence of steps in performing a complex procedure.

In a just published paper in Psychological Science, researchers at Carnegie Mellon University have found a way to find decode the procedural information required to tie various knots with enough precision to identify which knot is being planned or performed. To reach this conclusion, Drs. Robert Mason and Marcel Just first trained a group of participants to tie seven types of knots, and then scanned their brains while they imagined tying, or actually tied the knots while they were in an MRI scanner. The main findings were that each knot had a distinctive neural signature, so the researchers could tell which knot was being tied from the sequence of brain images collected. Furthermore, the neural signatures were very similar for imagining tying a particular knot and planning to tie it.

Dr. Just said, “Tying a knot is an ancient and frequently performed human action that is the epitome of everyday procedural knowledge, making it an excellent target for investigation.”