Exosomes are small extracellular membrane-based vesicles with a variety of 
cargoes that are involved in numerous physiological and pathological processes 
in the nervous system. Accumulating evidence has implicated that exosomes are 
emerging as a novel form of intercellular communication within the nervous 
system. In this review, we first illustrate exosome metabolism including its 
formation, secretion, transport, and uptake. Second, we compare exosomes to 
synaptic vesicles in terms of intercellular messengers and communicators. Third, 
we discuss the roles and prospects of exosomes in the diagnosis and treatment of 
neurodegenerative diseases.