The ability to process, comprehend, and respond to sensory information from one’s body parts.
Proprioception also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement and body position. It is sometimes described as the “sixth sense”.
Proprioception is mediated by proprioceptors, mechanosensory neurons located within muscles, tendons, and joints. There are multiple types of proprioceptors which are activated during distinct behaviors and encode distinct types of information: limb velocity and movement, load on a limb, and limb limits. Vertebrates and invertebrates have distinct but similar modes of encoding this information.
The central nervous system integrates proprioception and other sensory systems, such as vision and the vestibular system, to create an overall representation of body position, movement, and acceleration.
The sense of proprioception is ubiquitous across mobile animals and is essential for the motor coordination of the body. Proprioceptors can form reflex circuits with motor neurons to provide rapid feedback about body and limb position. These mechanosensory circuits are important for flexibly maintaining posture and balance, especially during locomotion. For example, consider the stretch reflex, in which stretch across a muscle is detected by a sensory receptor (e.g., muscle spindle, chordotonal neurons), which activates a motor neuron to induce muscle contraction and oppose the stretch. During locomotion, sensory neurons can reverse their activity when stretched, to promote rather than oppose movement.