Changes

The '''proprioceptive system''' is a sensory system that provides information about the position, movement, and [[orientation]] of the body.

A '''proprioceptive system''' is a sensory system within a human body that provides information about the position, movement, and [[orientation]] of the body.

A human's interaction with his environment depends on signals coming from the body that allows it to respond to its surroundings.<ref name=”1”>Han, J., Waddington, G., Adams, R., Anson, J. and Liu, Y. (2016). Assessing proprioception: a critical review of methods. Journal of Sport and Health Science, 5: 80-90</ref><ref name=”2”>Proske, U. and Gandevia, S. C. (2012). The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force. Physiological Reviews, 92: 1651-1696</ref>  

A human's interaction with his environment depends on signals coming from the body that allows it to respond to its surroundings.<ref name=”1”>Han, J., Waddington, G., Adams, R., Anson, J. and Liu, Y. (2016). Assessing proprioception: a critical review of methods. Journal of Sport and Health Science, 5: 80-90</ref><ref name=”2”>Proske, U. and Gandevia, S. C. (2012). The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force. Physiological Reviews, 92: 1651-1696</ref>  

This allows a person to maneuver around obstacles in the dark, or to manipulate objects out of view, for example.

This allows a person to maneuver around obstacles in the dark, or to manipulate objects out of view, for example.

This internal sense, often referred to as the sixth sense, is called proprioception.

As an example to show the impact of the absence of proprioception, moving a finger would be extremely difficult. Without proprioception the brain cannot feel what the finger is doing, and the process of moving it would have to be carried in a more conscious and calculated way, compensating the loss of positional feedback with vision. Another example that shows the relevance of proprioception is driving. Drivers are able to keep their eyes on the road while adjusting their arms and hands on the wheel, and applying the correct amount of pressure to the pedals.<ref name=”1”></ref><ref name=”3”> Surve, S. (2009). What is proprioception? Retrieved from http://brainblogger.com/2009/06/09/what-is-proprioception</ref><ref name=”4”> SPD Australia. The proprioceptive system. Retrived from http://www.spdaustralia.com.au/the-proprioceptive-system</ref>

As an example to show the impact of the absence of proprioception, moving a finger would be extremely difficult. Without proprioception the brain cannot feel what the finger is doing, and the process of moving it would have to be carried in a more conscious and calculated way, compensating the loss of positional feedback with vision. Another example that shows the relevance of proprioception is driving. Drivers are able to keep their eyes on the road while adjusting their arms and hands on the wheel, and applying the correct amount of pressure to the pedals <ref name=”1”></ref><ref name=”3”> Surve, S. (2009). What is proprioception? Retrieved from http://brainblogger.com/2009/06/09/what-is-proprioception</ref><ref name=”4”> SPD Australia. The proprioceptive system. Retrived from http://www.spdaustralia.com.au/the-proprioceptive-system</ref>.

Proprioception is not bounded by visual cues. Even when vision is absent, there is a correct sense of limb position. At any time, a person still knows the position of the different body parts during a movement and has an accurate map of their position in space. Therefore, the proprioceptive system allows precise placements such as touching the tip of the nose with the eyes closed.<ref name=”5”> Fortier, S. and Basset, F. A. (2012). The effects of exercise on limb proprioceptive signals. Journal of Electromyography and Kinesiology, http://dx.doi.org/10.1016/j.jelekin.2012.04.001</ref>

Proprioception is not bounded by visual cues. Even when vision is absent, there is a correct sense of limb position. At any time, a person still knows the position of the different body parts during a movement and has an accurate map of their position in space. Therefore, the proprioceptive system allows precise placements such as touching the tip of the nose with the eyes closed <ref name=”5”> Fortier, S. and Basset, F. A. (2012). The effects of exercise on limb proprioceptive signals. Journal of Electromyography and Kinesiology, http://dx.doi.org/10.1016/j.jelekin.2012.04.001</ref>.

Perception “is the identification, organization, and interpretation of sensory information, in order for humans to internally represent and understand the environment.”<ref name=”1”/> Perceptions need signals within the nervous system. These derive from physical stimulation of the various sense organs. In the same way, proprioception requires the stimulation of mechanoreceptors via changes of body position. Specifically, proprioception pertains to the perception of body position and movements in a 3D space. The peripheral mechanoreceptors provide proprioceptive information to the brain, in order for it to integrate and use them. The physical receptors (e.g. skin, muscles, or joints) can be seen as the hardware component, and the central processing that analyses the signals, the software.<ref name=”1”></ref><ref name=”4”></ref><ref name=”6”> Brain Balance. Proprioception explained. Retrieved from https://www.brainbalancecenters.com/blog/2015/08/proprioception-explained</ref>

Perception “is the identification, organization, and interpretation of sensory information, in order for humans to internally represent and understand the environment <ref name=”1”></ref>.” Perceptions need signals within the nervous system. These derive from physical stimulation of the various sense organs. In the same way, proprioception requires the stimulation of mechanoreceptors via changes of body position. Specifically, proprioception pertains to the perception of body position and movements in a 3D space. The peripheral mechanoreceptors provide proprioceptive information to the brain, in order for it to integrate and use them. The physical receptors (e.g. skin, muscles, or joints) can be seen as the hardware component, and the central processing that analyses the signals, the software <ref name=”1”></ref><ref name=”4”></ref><ref name=”6”> Brain Balance. Proprioception explained. Retrieved from https://www.brainbalancecenters.com/blog/2015/08/proprioception-explained</ref> (1; 4; 6).

It was demonstrated that proprioception as a measure of neuromuscular response to a stimulus must involve sensory input, central processing, and motor output. Therefore, proprioception cannot be interpreted has only the afferent (hardware) part of the system, the cumulative neural input to the nervous system from the receptors located in muscles, joints and the skin.

It was demonstrated that proprioception as a measure of neuromuscular response to a stimulus must involve sensory input, central processing, and motor output. Therefore, proprioception cannot be interpreted has only the afferent (hardware) part of the system, the cumulative neural input to the nervous system from the receptors located in muscles, joints and the skin. Although muscles spindles are considered the main receptors of proprioceptive information, there is a complex array of different sources and the importance of central processing in proprioception has been increasing in recent years <ref name=”1”></ref>.

A deficit in proprioception will lead to a loss of controlled movements without continuous visual feedback, a severe difficulty in maintaining force or position, and tremors could develop. It is an essential sense for the coordination of movement.<ref name=”5”/>

A deficit in proprioception will lead to a loss of controlled movements without continuous visual feedback, a severe difficulty in maintaining force or position, and tremors could develop. It is an essential sense for the coordination of movement <ref name=”5”></ref>.

According to Proske et al. (2012), “the subject of proprioception lies at the boundary between neurophysiology and neuropsychology.” It can be considered a mysterious sense since we are largely unaware of it. In the absence of vision, the limbs positions is still known but there is no clearly defined sensation that can be identifiable. This can be explained by the predictability of proprioceptive signals. There is an awareness that a person is making a willed movement and so the sensory input that it generates is anticipated. In sensory physiology there is a concept that what we feel commonly represents the difference between what is expected and what actually occurs. Regarding proprioception, if there is no mismatch between the expected signals from a movement and those generated, there is no definable sensation, but the person still knows the location of their limbs precisely.<ref name=”5”></ref><ref name=”7”> Proske, U and Gandevia, S. C. (2009). The kinaesthetic senses. Journal of Physiology, 587(17): 4139-4146</ref>

According to Proske et al. (2012), “the subject of proprioception lies at the boundary between neurophysiology and neuropsychology.” It can be considered a mysterious sense since we are largely unaware of it. In the absence of vision, the limbs positions is still known but there is no clearly defined sensation that can be identifiable. This can be explained by the predictability of proprioceptive signals. There is an awareness that a person is making a willed movement and so the sensory input that it generates is anticipated. In sensory physiology there is a concept that what we feel commonly represents the difference between what is expected and what actually occurs. Regarding proprioception, if there is no mismatch between the expected signals from a movement and those generated, there is no definable sensation, but the person still knows the location of their limbs precisely <ref name=”5”></ref><ref name=”7”> Proske, U and Gandevia, S. C. (2009). The kinaesthetic senses. Journal of Physiology, 587(17): 4139-4146</ref>.

Besides the proprioceptive system, the vestibular system contributes to several conscious sensations as well as helping with movement and posture. Conscious sensations include the senses of limb position and movement, the sense of tension or force, the sense of effort, and the sense of balance. Kinaesthesia is a term that can be used to refer to sensations of limb position and movement. Conventionally, proprioception consists of four senses that consist of the conscious sensations described before, and it is the cumulative neural input to the central nervous system from various receptors that collect sensory information from the body.<ref name=”2”></ref>

Besides the proprioceptive system, the vestibular system contributes to several conscious sensations as well as helping with movement and posture. Conscious sensations include the senses of limb position and movement, the sense of tension or force, the sense of effort, and the sense of balance. Kinaesthesia is a term that can be used to refer to sensations of limb position and movement. Conventionally, proprioception consists of four senses that consist of the conscious sensations described before, and it is the cumulative neural input to the central nervous system from various receptors that collect sensory information from the body <ref name=”2”></ref>.

The control of a movement is dependent on the quality of the afferent input originated from the various somatosensory systems, like the interoceptors (for the detection of a stimulus within the body) and mechanoreceptors (specialized nerve endings) that are involved in proprioception. These mechanoreceptors can be located in the joints, capsules, ligaments, muscles, tendons and skin.<ref name=”2”></ref>

Traditionally, muscle spindles have been responsible for providing the primary signals that contribute for the sense of limb position. There are several studies that used muscle tendon vibration manipulation (which stimulates preferentially muscle spindles afferent) that have produced illusions of joint position and motion. Recently, the sense of effort has been gaining ground regarding its role in joint position sense. Finally, as mentioned, beyond the peripheral aspects of proprioception, there is a significant central component to sensing body positions and movements. This was discovered through studies in the 1970s that assessed “the accuracy of reaching to proprioceptive targets that were either established through active movement of the subject or passive displacement by the experimenter”.<ref name=”2”></ref><ref name=”8”> Goble, D. J., Noble, B. C. and Brown, S. H. (2010). Where was my arm again? Memory-based matching of proprioceptive targets is enhanced by increased target presentation time. Neuroscience Letters, 481: 54-58</ref>

 

Traditionally, muscle spindles have been responsible for providing the primary signals that contribute for the sense of limb position. There are several studies that used muscle tendon vibration manipulation (which stimulates preferentially muscle spindles afferent) that have produced illusions of joint position and motion. Recently, the sense of effort has been gaining ground regarding its role in joint position sense. Finally, as mentioned, beyond the peripheral aspects of proprioception, there is a significant central component to sensing body positions and movements. This was discovered through studies in the 1970s that assessed “the accuracy of reaching to proprioceptive targets that were either established through active movement of the subject or passive displacement by the experimenter” <ref name=”2”></ref><ref name=”8”> Goble, D. J., Noble, B. C. and Brown, S. H. (2010). Where was my arm again? Memory-based matching of proprioceptive targets is enhanced by increased target presentation time. Neuroscience Letters, 481: 54-58</ref>.

===Proprioception and kinaesthesis===

===Proprioception and kinaesthesis===

Both “proprioception” and “kinaesthesis” are terms that continue to be used in the scientific literature, sometimes with different interpretations according to the authors. Some researchers define proprioception as the sense of joint position only, while kinaesthesia as the conscious awareness of joint motion. Others consider kinaesthesia as one of the submodalities of proprioception. In this case, proprioception contains both joint position sense and the sensation of joint movement. This last definition is in accordance with the conceptualization of kinaesthesis that was originally coined by Bastian (1888): the ability to sense the position and movement of limbs and trunk. Dover and Powers (2003) include the joint position sense, kinaesthesia, and sense of tension or force as submodalities of proprioception. It has also been argued that “proprioception” and “kinaesthesis” can be synonymous <ref name=”1”></ref><ref name=”5”></ref><ref name=”7”></ref><ref name=”9”> Collins, D. F., Refshauge, G. T. and Gandevia, S. C. (2005). Cutaneous receptors contribute to kinesthesia at the index finger, elbow, and knee. Journal of Neurophysiology, 94: 1699-1706</ref><ref name=”10”> Proske, U. (2015). The role of muscle proprioceptors in human limb position sense: a hypothesis. Journal of Anatomy, 227: 178-183</ref><ref name=”11”> Dover, G. and Powers, M. (2003). Reliability of joint position sense and force-reproduction measures during internal and external rotation of the shoulder. Journal of Athletic Training, 38(4): 304-310</ref>.

Both “proprioception” and “kinaesthesis” are terms that continue to be used in the scientific literature, sometimes with different interpretations according to the authors. Some researchers define proprioception as the sense of joint position only, while kinaesthesia as the conscious awareness of joint motion. Others consider kinaesthesia as one of the submodalities of proprioception. In this case, proprioception contains both joint position sense and the sensation of joint movement. This last definition is in accordance with the conceptualization of kinaesthesis that was originally coined by Bastian (1888): the ability to sense the position and movement of limbs and trunk. Dover and Powers (2003) include the joint position sense, kinaesthesia, and sense of tension or force as submodalities of proprioception. It has also been argued that “proprioception” and “kinaesthesis” can be synonymous <ref name=”1”></ref><ref name=”5”></ref><ref name=”7”></ref><ref name=”9”> Collins, D. F., Refshauge, G. T. and Gandevia, S. C. (2005). Cutaneous receptors contribute to kinesthesia at the index finger, elbow, and knee. Journal of Neurophysiology, 94: 1699-1706</ref><ref name=”10”> Proske, U. (2015). The role of muscle proprioceptors in human limb position sense: a hypothesis. Journal of Anatomy, 227: 178-183</ref><ref name=”11”> Dover, G. and Powers, M. (2003). Reliability of joint position sense and force-reproduction measures during internal and external rotation of the shoulder. Journal of Athletic Training, 38(4): 304-310</ref>.