New concepts in sensory system and immunosensory system

We describe new concepts in sensory system and immunosensory system. Sensory receptors have been assumed to be sensors that send information of outer world to the brain. However, cooling the skin evokes cold sensation, but not temperature. Hence, information may not be sent to the brain. Instead, we have proposed that receptors are comparators, which evoke impulses as drive signals when stimulus is adequate. When these impulses activate information stored in the brain, sensation of outer world would appear. Immunosensing represents the ability of the central nervous system (CNS) to respond to microbial infection occurring outside the CNS in spite of the presence of blood-brain barrier. Recent studies revealed cellular and molecular cascade of immunosensory system, in which immune cells, endothelial cells, and neurons are functionally connected by 2 types of soluble mediators, i.e, cytokines and prostaglandin E₂.