Regulation of odorous food on saliva secretion.

People can smell the smell of food. It is this smell that stimulates olfactory nerve receptors and produces nerve impulses, which are transmitted to the cerebral cortex along the sensory nerves, and then to the nasal cavity and oral sensory organs through motor nerves after analysis and judgment by the cerebral cortex, so that the sensory organs can produce sense of smell. This is neuromodulation.