Perception & Cognition
Revised from J.S.Longstaff (1996 & 2003)
Proprioceptors in: muscles, joints, tendons, labyrinth.
Sherringtons distinctions are often followed closely (Dickinson, 1974, p. 10; Ellison, 1993, p. 75; Rock, 1968) and also have been misrepresented. For example Wells and Luttgens (1976, p. 58) consider proprioceptors (together with visceroceptors) to be a type of interoceptor, contrary to Sherrington who explicitly distinguishes between the two.
Somaesthesia (or, somesthesis, somatosensory) is used very similar to proprioception in that they both refer to perceptions arising out of one's own body (from Greek soma, the body). Somaesthesia refers to sensations of body movements and positions, and also to sensations of temperature, pressure, touch, and pain (Collins, 1986). It is generally used to refer to stimulation arising from receptors in muscles, tendons, joints and skin (not vestibular) (Bles, 1981; Lackner and DiZio, 1984; Taub et al., 1973; 1975). The muscle/tendon/joint/skin conception of somaesthesia is sometimes considered to be synonymous with kinesthesis (English and English, 1974).
Gibson (1966, pp. 50, 53) proposed a sub-group within proprioception which he termed the haptic system with its mode of attention as touching and using sensory data from receptors in skin, joints, muscles, and tendons to produce perceptions about the environment or the body. The hands and other body members are considered to be the organs of perception. The haptic system can derive information about ones own body or about the exterior environment (eg. feeling the shape of an object) and so is both proprioceptive and exteroceptive. Haptic is from the Greek haptein, to touch, (Collins, 1986) and so is identical with the generalised notion of the sense of touch (see above).
Gibson (1966, pp. 36-37) also includes
Similarly, other researchers use the terms
Receptors in skin which can receive stimulation from the exterior environment will also respond to stimulation from body movement. Thus these must be classified as both proprioceptors and exteroceptors. Bastian (1888), who proposed the term kinesthesia stated this same fact at the outset, that the group of sensations under the name of kinaesthesis . . . is confessedly a mixed group partly intrinsic and partly extrinsic in their origin (p. 6).
Inconsistent use of Kinesthesia vs Proprioception.
Another problem is that the terms kinesthesia and proprioception are not consistently defined. Typically the two terms are used synonymously (Clark and Horch, 1986; Schmidt, 1982, p. 202) and Moberg (1983, p. 1) considers kinesthetic sensibility, position sense, muscle sense or proprioception as synonyms. Similarly, sometimes the term visual proprioception(Lee and Aronson, 1974; Lee and Lishman, 1975), is used, while others refer to this as visual kinesthesis (Lishman and Lee, 1973; Rieger, 1983; Warren et al., 1988, p. 646).
The particular components included within kinesthesis or proprioception also vary among authors. In the narrowest view stimulation arising from receptors in muscles, tendons, and joints (not labyrinth or skin) are included as proprioceptors (Fitt, 1988, p. 266) or as kinesthetic (Laszlo and Bairstow, 1971).
In a slightly broader view, Bastian (1888, p. 5) considered receptors in muscles, tendons, joints and skin (but not vestibular) as being kinesthetic. Perhaps vestibular was not included because Bastian focused on the positions and movements of our limbs (p. 6) rather than linear or rotary self-motion (see below). Other writers also follow this same view of including stimulation from muscle, joint, tendon, and skin (but not vestibular) receptors as being kinesthetic (Clark and Horch, 1986) or as proprioceptive (Rothwell, 1987, p. 74), or as proprioceptive considered synonymous with somatic sensation (Taub and Berman, 1968). Similarly, Souder (1972, p. 14) considers the vestibular labyrinth to be a separate system from either kinesthetic or proprioceptive. Sherrick and Cholewaik (1986, p. 111-3) consider the cutaneous sense to be exteroceptive but also that the senses of the skin do occasional duty as supplement to the kinesthetic senses. Wells and Luttgens (1976, pp. 5861) include skin receptors as being proprioceptive only when they participate in withdraw and thrust reflexes.
Other authors use Sherringtons (1906) original distinctions of including sensations arising from muscle, tendon, joint, and labyrinth (but not skin) receptors within proprioception (Dickinson, 1974; Ellison, 1993, p. 75; Rock, 1968).
In the broadest view, visual, audio, skin and labyrinth receptors are included together with receptors in muscles, tendons and joints as all contributing to kinesthesia (Rasch and Burke, 1978, pp. 80-81), or to proprioception (Gibson, 1966, pp. 36-37), or as kinesthesia considered synonymous with proprioception (Schmidt, 1982, chapter 6):
Historically, kinesthesis . . . was a term limited to a persons perception of his or her own motion, both of the limbs with respect to one another, and also of the body as a whole. Sherringtons (1906) term proprioception was originally used to mean the perception of movement of the body plus its orientation in space (even though it may not be moving). Over the years these two terms have become practically synonymous, and it is probably not important to continue this distinction.(Schmidt, 1982, p. 202)
Other researchers might arrange kinesthesia and proprioception into a kind of hierarchy, however these arrangements tend to vary. The proprioceptive system is sometimes considered as a higher-order system containing the separate kinesthetic and vestibular systems (Riesser and Pick, 1976; Sherrick and Cholewaik, 1986). Strelow and Babyn (1981, p. 191) list vestibular, kinaesthetic, and proprioceptive information implying that the three are separate. Singleton (1972, p. 61) represents the somaesthetic system as containing the proprioceptive system and the tactile system. The proprioceptive system is then further subdivided as containing the kinesthetic system (including receptions from muscles, tendons, and joints) which is separate from the vestibular system.
Kinesthesia & Proprioception as Conscious & Unconscious.
Kinesthesia is sometimes used to refer to conscious perceptions since the Greek root aesthesia means to perceive, while proprioception is not necessarily conscious but may occur as unconscious sensory receptions which elicit reflex reactions. This conception places kinesthesia as a higher-order derivative which calls on proprioception for its data.
Much of Sherringtons (1906) research which distinguished the term proprioception focused on reflex actions produced when stimulating particular receptors. McCloskey (1978, p. 764) also describes that Sherrington used proprioception to refer to vestibular sensations and inputs from muscles and joints that are not necessarily perceived and other authors explicitly refer to the conscious/unconscious distinction between kinesthesia and proprioception (Ellison, 1993, p. 75; Paillard and Brouchon, 1974, p. 275). Correspondingly, in Lee and Lishmans studies of vision and body movement, they use:
visual kinaesthesia (Lishman and Lee, 1973) when they are studying subjects conscious perceptions of their own self-motion, whereas they use
Research has also focused on whether sensory discharges from muscle spindle receptors have any direct access to conscious perception (kinesthesia) or are used solely for subconscious reflexive control of movement (proprioception). This question has been referred to as the problem of conscious proprioception, whether there is awareness of muscle length and tension changes (Gelfan and Carter, 1967).
Some evidence indicates that sensory reception from muscles is not consciously perceived. Anaesthestized joints produces a loss of perception of passive movement or position in the finger joint (Provins, 1958) or the toe (Browne et al., 1954) even though the muscles which act upon these joints were unaffected by the anaesthesia. Stretching a muscle by pulling on the exposed tendon does not produce any conscious perception of limb movement in the fingers, hand, or foot and so Gelfan and Carter (1967) conclude that there is no muscle sense in man. This effect was duplicated by Moberg (1983) who stresses the importance of skin receptors (rather than joint or muscle receptors) for conscious kinesthesia in the fingers and hand.
However other evidence indicates that muscles do play a role in conscious perception. Sensory impulses from muscle spindle receptors have been found to have direct connections to the cerebral cortex in baboons (Phillips et al., 1971) and cats (Oscarsson and Rosen, 1963). When muscles acting on the fingers are lightly tensed or voluntarily moved then motion is perceived even if the joints and skin have been paralysed (Goodwin et al., 1972a; 1972b). This sensory facilitation of actively moved versus passively manipulated muscles was also noted earlier (Browne et al., 1954). Illusions of forearm movements and false positions have also been elicited by vibrating the muscles and tendons with a physiotherapy vibrator (Goodwin et al., 1972a; 1972c).
Distinguishing receptors as to whether their stimulation become conscious or unconscious appears to be a tentative affair. This is especially true since conscious perceptions rarely arise solely from the sensations of one individual receptor, especially in kinesthesia where input from an abundance of receptors is combined into a unified perception. Conscious kinesthesia is not attributed to particular receptors per se, but as a phenomenological experience of the bodys positions, motions, forces etc. In McCloskeys (1978) exhaustive review of kinesthetic sensibility, and in particular the question of Are muscles sentient?, it is noted that perceptions are not experienced in the receptors, but in the objects perceived:
. . . we are no more likely to feel kinesthetic sensations in our muscles or joints than we are to hear sounds in our heads or see objects in our retinas - but[conscious kinesthesia] would be sensations of movement, or force, or tension, or of altered position in the parts moved by the muscles. (McCloskey, 1978, p. 777 [emphasis his])
It would not be beneficial for the raw data from receptors to be available to consciousness since the data from collections of receptors must be interpreted relative to each other and to exterior forces (gravity, momentum, external objects) and relative to any motor commands which have been executed. These will all influence the significance of any isolated receptor response:
. . . the essential point is that it would be of little value for the highest sensory centres to receive raw data from the muscle afferents, because what these mean depends entirely upon what the relevant muscle is being told to do by the motor system.(Goodwin et al., 1972a, p. 744)
Likewise, in a study of the history of proprioception Dickinson (1974, p. 10) concludes that at a physiological level, the absence of a direct link from receptors to the cortex may not necessarily preclude some indirect participation in perception since the perception is derived at an unconscious level anyway.
Conclusions; Working Definitions.
From the overlapping concepts of somaesthesia, kinesthesia, proprioception, etc. outlined above, the following working definitions can be used in an integrated model.
Proprioception is not favored since it belongs to an interior/exterior distinction which has been shown to be invalid. In Dickinsons (1974) historical review of proprioception it is observed that Not only is there disagreement concerning the definition of proprioception, there is even disagreement over whether proprioception may be viewed as a sensory modality (p. 9). Clark and Horch (1986, p. 13.2) state that the term proprioceptive lacks a precise definition and therefore they prefer kinesthesia.
Kinesthesia will be used in its broadest sense to refer to perceptions arising from muscle, tendon, joint, skin, vestibular, visual, and audio receptors. In addition, an interior knowledge of motor commands or efferent data can be considered to be another source of kinesthetic information (see below).
Other senses can be conceived to be kinesthetic sub-systems. These include limb position sense, limb movement sense, sense of linear or rotary self-motion, sense of balance or equilibrium, and the sense of force.
Somatic is generally used in its typical definition of referring to perceptions arising from within the physical mass of the body itself, namely from receptors in muscles, tendons, joints, and skin. These receptors comprise a complete grouping in themselves within the larger group of kinesthetic receptors. This somatic system is synonymous with the haptic system but since haptic comes from to touch it is more associated with skin receptors rather than the integrated functioning of receptors within the somatic system.