Fig. 1

The olfactory conduction pathway. The olfactory epithelium comprises three cell types: olfactory sensory neurons (OSNs), supporting cells, and basal cells. After OSNs capture odor molecules, the axons of neurons expressing the same odorant receptors converge to several well-defined glomeruli in the olfactory bulb (OB), where they transmit signals to mitral cells. The axons of the mitral cells leave the OB and project to the higher olfactory cortex, including the piriform cortex, hippocampus, and amygdala, to generate the sense of smell. Misfolded protein aggregates transfer between the olfactory system and the central nervous system via olfactory pathways. The red dots represent seeds