Taken together, the study’s findings represent a crucial step forward in addressing many unresolved issues regarding Long COVID. The systemic increase in AMPARs provides a direct biological explanation for the cognitive symptoms, highlighting a target for potential treatments. For example, drugs that suppress AMPAR activity could be a viable approach to mitigate brain fog. Interestingly, the team’s analysis also demonstrated that imaging data can be used to distinguish patients from healthy controls with 100% sensitivity and 91% specificity.

As explained in their paper, published in Brain Communications on October 1, 2025, the team hypothesized that patients with brain fog might exhibit disrupted expression of AMPA receptors (AMPARs)—key molecules for memory and learning—based on prior research into psychiatric and neurological disorders such as depression, bipolar disorder, schizophrenia, and dementia. Thus, they used a novel method called [^11^C]K-2 AMPAR PET imaging to directly visualize and quantify the density of AMPARs in the living human brain.

By comparing imaging data from 30 patients with Long COVID to 80 healthy individuals, the researchers found a notable and widespread increase in the density of AMPARs across the brains of patients. This elevated receptor density was directly correlated with the severity of their cognitive impairment, suggesting a clear link between these molecular changes and the symptoms. Additionally, the concentrations of various inflammatory markers were also correlated with AMPAR levels, indicating a possible interaction between inflammation and receptor expression.

more than four years after the onset of the COVID-19 pandemic...

Uhh, hmmm.... I mean, technically true I guess.

Nice, hopefully someone will come up with a treatment for symptoms or (fingers crossed) a way to reverse the effects.

This makes me wonder how can one tell that the brain fog is from COVID and not increasing amount of daily stress factors, malnutrition etc etc