> ... Have found signs that the virus can establish a foothold of sorts on the periphery of the brain, where the protective blood-brain barrier opens up to allow key molecules to slip through. One of those places is the olfactory bulb ... Yet scientists have so far found little evidence that the virus penetrates any deeper than that. Instead, they’ve seen the type of damage caused by strokes, as well as the blood clots that may have precipitated them. That’s part of why Boldrini and many others suspect that inflammation — the immune system’s all-hands-on-deck response to an invader — may play an essential role in the brain damage experienced by COVID-19 patients. Inflammation can trigger blood clots, and once a clot forms, inflammation increases around it. It’s similar to what’s seen in people who experience traumatic brain injury ... [Such] people ... [may show] sudden changes in behavior and personality [including] suicide ... It’s eerily similar to what many COVID-19 patients face
> COVID-19 damages the hippocampus. That could help explain why some patients have lingering issues with depression and anxiety. If this damage is caused by inflammation, it probably wreaks havoc in several ways. Scientists suspect it disrupts the flow of serotonin ... and prompts the body to make kynurenine instead, even though it’s toxic to neurons. Inflammation also triggers coagulation, creating clots that can block blood flow to cells and kill them. And it activates the microglia, which may attempt to remove more neurons than they normally would.
> COVID-19 damages the hippocampus. That could help explain why some patients have lingering issues with depression and anxiety. If this damage is caused by inflammation, it probably wreaks havoc in several ways. Scientists suspect it disrupts the flow of serotonin ... and prompts the body to make kynurenine instead, even though it’s toxic to neurons. Inflammation also triggers coagulation, creating clots that can block blood flow to cells and kill them. And it activates the microglia, which may attempt to remove more neurons than they normally would.