Many of the known coronaviruses are neurotropic, meaning they are able to infect neuron cells. If these observed trends carry over to SARS-CoV-2, they could help to elucidate how the CNS is affected by COVID-19. Some of the key observations include:

• human coronavirus OC43 was shown to transmit itself to different neurons via axons in mice
• neuronal ACE2 expression in mice was found to be in different pre-autonomic regions of the brain which could explain why infected COVID-19 patients with dangerously low blood oxygen levels don't gasp for air
• SARS-CoV was found to infect regions of the brain that deal with cardiopulmonary regulation in human ACE2 knock-in mice
• SARS-CoV patient autopsies showed that the virus affected neurons more than any other kind of cell