Diagram of ACE2 regions in the brain

COVID directly invades the brain

Neuroinvasion is the technical name for this route of infection. In this case, the virus can go directly up through the nose, via what is called sustenacular cells, to the olfactory bulb. Then it can replicate or move up synapses from the olfactory nerve to the central parts of the brain, potentially.

UC Davis released a statement on the researchwhich was published in Cell reports. The statement included the following:

Using a recently developed non-human primate model of the disease, UC Davis researchers have revealed that COVID reaches the brain by transport through the nose along the olfactory nerve, a nerve that begins in the brain and ends. in the upper inner part of the nose.

“We have not only demonstrated that the virus infects the brain, but also that it directly infects neurons and can be transported along nerve pathways to sites beyond the initial olfactory regions,” said lead author John Morrison, professor of neurology at UC Davis and director of the CNPRC [California National Primate Research Center].


Their findings leave no doubt that the virus was entering the brain and damaging brain cells along the way, said first author Danielle Beckman, a postdoctoral fellow at UC Davis. By comparing young and old animals, it became clear that viral infection was exacerbated in older animals. The brain cells of infected aged monkeys appeared to be shrunken.

This is important because of the neurocytoarchitectural areas to which the olfactory bulb connects. One of these structures may be very familiar to you: the amygdala, also known as the brain’s “fear centre.” (Really, it is designed to detect the threat; fear is a bodily state, not an environmental signal.)

Other vital connecting areas are those that, along with the amygdala, help encode memory. That’s why many researchers have sounded the alarm that Long Covid could produce its own version of dementia, ordering Alzheimer’s if not triggering Alzheimer’s itself:

Perhaps most striking is how far the virus has traveled in older animals compared to healthy young animals. While the virus was mainly found in the primary olfactory cortex in all inoculated animals, the virus spread more in older animals. Cellular markers of SARS-CoV-2 have been observed in regions of the brain extending beyond immediate sensation and the perception of smell, and in areas strongly involved in emotion, memory and cognition in older animals. These findings raise concerns about potential spikes in neurodegenerative disease and susceptibility to dementia-related diseases, such as Alzheimer’s disease, as infected adults age.

“In older monkeys in particular, the virus infects neurons in regions known to be highly vulnerable to Alzheimer’s disease,” said Morrison.

(Emphasis ours.)

Now, what was the culprit: the virus itself or the inflammation as a downstream process? It seems like it has yet to be explained, but suffice it to say that the two could be happening simultaneously; it doesn’t have to be one or the other. But the study showed that “the intensity with which SARS-CoV-2 induced inflammation in aged rhesus macaques resulted in significant damage,” according to one researcher.

I plan to write a lot more about this in the near future, but I wanted to quickly post this piece to give people more information, more ways for all of us to arm ourselves. These results are one more reason to continue masking! Get boosted (i.e. if your doctor doesn’t think it would be contraindicated); but also protect your respiratory tract! Keep this creature out of your nose.

Edited thank you this is just a test for a crucial fix to the link to study.

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