A Brazilian study published in the journal PNAS describes some of the effects infection by SARS-CoV-2 can have on the central nervous system. A preliminary version (not yet peer-reviewed) posted in 2020 was one of the first to show that the virus that causes COVID-19 can infect brain cells, especially astrocytes. It also broke new ground by describing alterations in the structure of the cortex, the most neuron-rich brain region, even in cases of mild COVID-19.

The cerebral cortex is the outer layer of gray matter over the hemispheres. It is the largest site of neural integration in the central nervous system and plays a key role in complex functions such as memory, attention, consciousness, and language.