The nervous system is by far the most complicated system in your horse's body. A large proportion of which creates much of your horse's personality and functionality. The system is made up of 2 subsystems:
The central nervous system
Consisting of the brain and spinal chord
The peripheral nervous system
Consisting of the cranial and spinal nerves, nerve ganglia and the autonomic nervous system.
The central nervous system is largely responsible for your horse's behaviour. It also controls your horse's senses, in conjunction with the peripheral nervous system. Everything your horse sees, feels, tastes and hears is deciphered by the central nervous system.