Cutaneous Receptors Contribute to Kinesthesia at the Index Finger, Elbow, and Knee

Abstract

The neural mechanisms underlying the sense of joint position and movement remain controversial. While cutaneous receptors are known to contribute to kinesthesia for the fingers, the present experiments test the hypothesis that they contribute at other major joints. Illusory movements were evoked at the interphalangeal (IP) joints of the index finger, the elbow, and the knee by stimulation of populations of cutaneous and muscle spindle receptors, both separately and together. Subjects matched perceived movements with voluntary movements of homologous joints on the contralateral side. Cutaneous receptors were activated by stretch of the skin (using 2 intensities of stretch) and vibration activated muscle spindle receptors. Stimuli were designed to activate receptors that discharge during joint flexion. For the index finger, vibration was applied over the extensor tendons on the dorsum of the hand, to evoke illusory metacarpophalangeal (MCP) joint flexion, and skin stretch was delivered around the IP joints. The strong skin stretch evoked the illusion of flexion of the proximal IP joint in 6/8 subjects (12 +/- 5 degrees, mean +/- SE). For the group, strong skin stretch delivered during vibration increased the perceived flexion of the proximal IP joint by eight times with a concomitant decrease in perceived flexion of the MCP joint compared with vibration alone (P < 0.05). For the elbow, vibration was applied over the distal tendon of triceps brachii and skin stretch over the dorsal forearm. When delivered alone, strong skin stretch evoked illusory elbow flexion in 5/10 subjects (9 +/- 4 degrees). Simultaneous strong skin stretch and vibration increased the illusory elbow flexion for the group by 1.5 times compared with vibration (P < 0.05). For the knee, vibration was applied over the patellar tendon and skin stretch over the thigh. Skin stretch alone evoked illusory knee flexion in 3/10 subjects (8 +/- 4 degrees) and when delivered during vibration, perceived knee flexion increased for the group by 1.4 times compared with vibration (P < 0.05). Hence inputs from cutaneous receptors, muscle receptors, and combined inputs from both receptors likely subserve kinesthesia at joints throughout the body.

Processing Afferent Proprioceptive Information at the Main Cuneate Nucleus of Anesthetized Cats

“…Cutaneous and deep muscular feedback converge on vertebrate spinal central pattern generators (Hultborn and Nielsen, 2007) but ascend through parallel paths up to the cerebral primary somatosensory cortex, where convergence of both submodalities is subliminal (Zarzecki and Wiggin, 1982;Kang et al, 1985) but could reach threshold when arriving within a short time window, allowing summation of effects. In fact, cutaneous and spindle information potentiate each other in humans, in whom removal of cutaneous feedback from a moving digit decreases proprioceptive acuity (Provins, 1958), and illusion of movement induced by stretching the skin over joints (Edin and Johansson, 1995;Collins et al, 2005) increases when vibration and skin stretch are applied together (Collins and Prochazka, 1996).…”

The role of sensory signals in perception of the body

“…When a skin stretch is applied to the dorsal side of the interphalangeal joints of the index finger, an illusion of index finger flexion is created 19) . Stretch-induced illusory motion is also obtained at the elbow and knee 20) . However, illusions of joint position changes induced by skin stretch seem to be less potent than the ones induced by muscle vibration 19,20) .…”

“…Stretch-induced illusory motion is also obtained at the elbow and knee 20) . However, illusions of joint position changes induced by skin stretch seem to be less potent than the ones induced by muscle vibration 19,20) . Cutaneous signals also modulate perceived body size.…”

Is there “arthrogenic inhibition” of cutaneous reflexes in subjects with functional ankle instability?

“…This was based, for example on findings from Collins and Prochazka (1996), showing that it was possible to evoke movement illusions by ensemble cutaneous input from the dorsum of the human hand. Later, Collins et al (2005) demonstrated that cutaneous receptors contribute to kinesthesia at the knee. These findings were extended to the ankle by Aimonetti et al (2007) by showing that cutaneous afferents provide a neuronal population vector that encodes the orientation of human ankle movements.…”