Fig. 2.

Possible distribution pathways of CNS infection with HCoVs: (1) olfactory nerve to olfactory cortex of temporal lobe to hippocampus to amygdala, or to hypothalamus; (2) via serotoninergic dorsal raphe system; (3) through hematogenous route and Virchow-Robin spaces; (4) via lymphatic system. (Dissemination pathways with empirical data are designated by solid indicators, and theoretical ones are indicated by dot arrows.) This figure is

modified from Cheng et al. (2020) with permission