A sensory neuron is a cell of the nervous system responsible for converting external stimuli from the environment of the organism into electrical signals. Some sensory neurons can respond to tactile stimuli while others can be activated by motor neurons in order to cause the contracture of muscles. This form of connection between sensory and motor neurons is linked to the motor reflex loop, as well as several forms of involuntary behavior, such as A large number of reflex circuits are located in the spinal cord in humans.