Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Proprioception”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed2006

Neuronal circuitry and synaptic organization of trigeminal proprioceptive afferents mediating tongue movement and jaw-tongue coordination via hypoglossal premotor neurons.

The neural framework and synaptic organization of trigeminal proprioceptive afferent-mediated jaw-tongue coordination were studied in rats using multiple electrophysiological and neuroanatomical approaches. Electrostimulation of the masseter nerve evoked short-latency responses (5.86 +/- 2.59 ms) in hypoglossal premotor pools including the parvocellular (PCRt) and intermediate (IRt) reticular nuclei and the dorsomedial part of the spinal trigeminal nucleus oralis (Vodm) and interpolaris (Vidm). Biocytin-labelled axon terminals from these areas traveled into the hypoglossal nucleus (XII) and contacted motoneurons. Double labelling of biotinylated dextran amine (BDA) tracing and cholera toxin B (CTB) transport demonstrated that labelled axons and terminals from the mesencephalic trigeminal nucleus (Vme) overlapped with XII premotor neurons in the alpha division and in PCRt, IRt, Vodm and Vidm. Confocal microscopic observations revealed that Vme terminals closely contacted XII premotor neurons. Dual labelling of intracellular neurobiotin staining of jaw-muscle spindle afferents (JMSAs) combined with horseradish peroxidase (HRP) retrograde transport revealed that 498 JMSA boutons apposed to 146 HRP-labelled premotor neurons. Electron microscopic observations demonstrated that 127 JMSA boutons made both axodendritic (68%) and axosomatic (32%) synapses with XII premotor neurons. Eighty-three per cent of synapses were asymmetric and the rest (17%) were symmetric. Thirty-nine per cent of JMSA boutons received presynaptic contacts from P-type terminals. Varieties of synaptic organizations were found. These results provide evidence that trigeminal proprioceptive afferents mediate jaw-tongue coordination through XII premotor neurons. Ultrastructural findings demonstrated that synapses between JMSA boutons and XII premotor neurons are predominantly excitatory, and synaptic transmission to XII motoneurons is modified on XII premotor neurons by presynaptic mechanisms. These frameworks and synaptic organizations are most probably the neural substrate for trigeminal proprioceptive afferent-mediated jaw-tongue coordination.

Afferent Pathways↗
PubMed1997

Control of motor units in human flexor digitorum profundus under different proprioceptive conditions.

1. Changing the posture of the human fingers can functionally 'disengage' the deep finger flexor muscle from its normal action on the terminal phalanx of the fourth (or third) finger. This enables the activity of the muscle to be studied both with and without its normal proprioceptive inputs. 2. Spike trains of long duration from pairs of concurrently active motor units in this muscle were recorded in both the engaged and disengaged hand postures. Subjects voluntarily kept one of the motor units (the 'controlled' unit) discharging at the same target frequency in both postures. The strength of short-term synchrony, the strength of common drive, and the variability of discharge of these pairs of motor units were determined in both postures. 3. All subjects reported that the effort required to activate the motor units in the disengaged hand posture was substantially greater than in the normal engaged posture. 4. Short-term synchrony, which is a function of common corticospinal inputs to pairs of motor units, was similar in both hand postures. However, the strength of common drive was significantly decreased when the muscle was disengaged. Although the neural substrate for common drive is not known, this observation suggests that proprioceptive feedback is involved either directly or indirectly. 5. Although the discharge rate of the 'uncontrolled' motor units increased when the muscle was disengaged, the variability of discharge of these and the 'controlled' motor units increased significantly. This supports the idea that the precision with which fine motor tasks can be performed is improved when proprioceptive feedback is intact.

Action Potentials↗
PubMed2006

A prospective study on knee proprioception after meniscal allograft transplantation.

The meniscus plays an important role in the proprioceptive ability of the knee joint. The aim of this prospective study was to assess the short-term influence of a meniscus replacement on the proprioception of the knee. Fourteen patients who had undergone a fresh meniscal allograft transplantation between May 2001 and June 2003 were tested pre-operatively and 6 months post-operatively. Disability regarding pain, stiffness and functionality of the affected knee during daily activities was measured by the Western Ontario and McMaster Universities Arthritis (WOMAC) scale. The knee joint position sense was assessed using the Biodex System 3 isokinetic dynamometer. The results of the WOMAC scale showed no significant differences concerning pain, stiffness or knee function between the pre- and post-operative condition of the knee. Assessment of the knee joint position sense at a reference point of 70 degrees of knee flexion revealed a significant improvement of the proprioception of the operated knee at 6 months after surgery compared with the pre-operative condition. The results of this study suggest that although no significant improvement of pain and functionality of the operated knee occurred at this short-term follow-up period, a meniscal allograft transplantation seems to have a significant positive effect on the joint position sense of the previously meniscectomised knee.

Adolescent↗
PubMed1987

Stumbling reactions in man: significance of proprioceptive and pre-programmed mechanisms.

1. Electromyogram (e.m.g.) responses of the leg musculature and the corresponding joint movements were studied following a perturbation of the limb during walking on a treadmill, produced by a randomly timed treadmill acceleration impulse, either predictable, or unpredictable in its amplitude and rate of acceleration. 2. The rate of rise of ipsilateral gastrocnemius e.m.g. response following a perturbation was dependent on the rate of treadmill acceleration. For a given acceleration rate the amplitude of the e.m.g. response and the timing of its peak was dependent on the amplitude of the impulse and the rate of rise of the gastrocnemius response was the same for impulses of both small and large amplitude. The onset latency was shorter (65 ms) for high accelerations and longer (85 ms) for lower ones. 3. The amplitude of the ipsilateral biceps femoris response was much smaller than the gastrocnemius response but was larger following unpredictable than predictable impulses. 4. The initial gastrocnemius response was followed by a tibialis anterior activation associated with a gastrocnemius depression and sometimes with a second, weak gastrocnemius activation. The gastrocnemius depression ended within a fixed time range relative to the onset of the response. The tibialis anterior activation was most pronounced when unpredictable impulses with high acceleration but a small amplitude were induced. 5. It is concluded that generation of the first gastrocnemius response is obviously under continuous control by muscle proprioceptive information and can be best described in terms of a stretch reflex response. It is suggested that, on the evidence of the diphasic or triphasic e.m.g. pattern, a close interaction occurs between a central programme and muscle proprioceptive input in order to generate the appropriate e.m.g. pattern. 6. On the basis of earlier work (Berger, Dietz & Quintern, 1984a) and on the present results it is suggested that the e.m.g. responses may be mediated mainly by muscle proprioceptive input from group II afferents. This input is modulated and processed by spinal interneuronal circuits, closely connected with spinal locomotor centres. The mode of processing depends on various factors, such as the predictability of the nature of the impulse.

Adolescent↗
PubMed2003

Prism exposure affects the proprioceptive frames of reference for interlimb rhythmic coordination.

Adaptation to prisms can produce a change in felt arm position, termed proprioceptive shift. We studied the effects of prism-induced proprioceptive shift on interlimb rhythmic coordination performed under proprioceptive guidance, in the absence of vision. Relative to interlimb rhythmic coordination performed before prism exposure, the observed steady states of relative phase for postexposure coordination were shifted by a small but reliable amount. The shift was in the direction expected, given the direction of optical displacement. The amount of variability of interlimb rhythmic coordination was unaffected by prism exposure. The results suggest that the same spatial frames of reference altered by prism adaptation are involved in the production of interlimb rhythmic coordination patterns.

Adult↗
PubMed1990

The role of ocular muscle proprioception in visual localization of targets.

The role of ocular muscle proprioception in the localization of visual targets has been investigated in normal humans by deviating one eye to create an experimental strabismus. The passively deviated eye was covered and the other eye viewed the target. With a hand-pointing task, targets were systematically mislocalized in the direction of the deviated nonviewing eye. A 4- to 6-degree error resulted when the nonviewing eye was offset 30 degrees from straight ahead. When the eye was deviated, the perceived "straight-ahead" was also displaced, by a similar amount, in the same direction. Since the efferent motor commands to the displaced and to the nondisplaced eyes are presumably identical by the law of equal innervation, the mislocalization of visual objects must be attributed to the change in proprioceptive information issued from the nonviewing, deviated eye. Thus proprioception contributes to the localization of objects in space.

Humans↗
PubMed2005

Relative impact of radiographic osteoarthritis and pain on quadriceps strength, proprioception, static postural sway and lower limb function.

OBJECTIVE: To investigate the relative impact of radiographic osteoarthritis (ROA) and current knee pain on lower limb physical function, quadriceps strength, knee joint proprioception, and postural sway. METHODS: Using a 2x2 factorial design, 142 community derived subjects aged over 45 were divided into four subgroups based on the presence or absence of ROA (Kellgren & Lawrence>grade 2) and knee pain (as assessed by NHANES questions and a 100 mm visual analogue scale). Maximum isometric contraction of the quadriceps, knee joint proprioceptive acuity, static postural sway, and WOMAC index (both whole and function subscale) were assessed in all subjects. RESULTS: Compared with normal subjects, reported disability was greater for all other subgroups (p<0.01). Subjects with both ROA and knee pain reported the greatest disability, and those with knee pain only had greater disability than those with ROA only. Quadriceps weakness was observed in all groups compared with normal subjects (p<0.01), though they were no significant intergroup differences. Subjects with knee pain had a greater sway area than those without (p<0.05) but the presence of ROA was not associated with increased postural sway. No differences in proprioceptive acuity were observed between groups. CONCLUSIONS: The presence of knee pain has a negative association with quadriceps strength, postural sway, and disability compared with ROA. However, the presence of pain-free ROA has a significant negative influence on relative quadriceps strength and reported disability.

Aged↗
PubMed2006

Do voluntary strength, proprioception, range of motion, or postural sway predict occurrence of lateral ankle sprain?

Prevention of ankle sprain, the most common sporting injury, is only possible once risk factors have been identified. Voluntary strength, proprioception, postural sway, and range of motion are possible risk factors. A systematic review was carried out to investigate these possibilities. Eligible studies were those with longitudinal design investigating ankle sprain in subjects aged > or = 15 years. The studies had to have measured range of motion, voluntary strength, proprioception, or postural sway before monitoring incidence of lateral ankle sprain. Dorsiflexion range strongly predicted risk of ankle sprain. Postural sway and possibly proprioception were also predictors. Therefore the preliminary evidence suggests that people with reduced ankle dorsiflexion range may be at increased risk of ankle sprain.

Ankle Injuries↗
PubMed1995

Contribution of proprioception for calibrating and updating the motor space.

The absence of muscular proprioception, whether at a segmental or at a central level, impairs performance in several ways. The contribution of proprioception to movement control and learning is not easily dissociated from that of other sources of sensory information (e.g., vision). Therefore, the rare clinical cases of extensive neuropathy, depriving the brain massively and permanently of its presumed main sources of dynamogenic information from skin and muscles, are of very special interest. Two such patients and controls were tested in experiments investigating (i) force production, (ii) amplitude coding, (iii) spatial reference frames in pointing, and (iv) prismatic adaptation. Overall, our results highlight the key role of proprioceptive afferents for calibrating the spatial motor frame of reference, and the powerful substitutive properties of the central nervous system.

Adult↗
PubMed1995

Is proprioception important for the timing of motor activities?

This study tested whether a deafferented patient demonstrates impaired timing ability compared with four control subjects. By comparing normal subjects with the deafferented patient, some insight was expected on the importance of proprioception in timing of motor behavior. The protocol was set to enhance the strategy of the subjects in using feedbacks. Subjects had to synchronize finger taps with a sound produced at regular intervals. Once synchronized, the bips were muted and the subjects had to continue the tapping at the same pace. Interresponse interval (IRI) variability was measured under two feedback conditions: with and without vision and auditory feedback. The Wing and Kristofferson model (A.M. Wing and A.B. Kristofferson. Percept. Psychophys. 13(3): 455-460, 1973) was used to segment IRI variance into separate components: a central clock and a peripheral motor delay. When the deafferented patient saw and heard the outcome of her tapping movements, there was a greater variability in successive intervals between taps than when vison and hearing were blocked. We interpret this variability as indicating that the subject used auditory and visual feedback to maintain a correct overall rhythm. The patient may easily substitute visual and (or) auditory feedback for her defective proprioception for movement timing. However, this substitution proved to be inefficient in the limited training period provided in this experiment. The results suggest that the proprioceptive contribution to the time-keeping mechanism presumably depends on the presence of an efference copy signal.

Efferent Pathways↗
PubMed1994

Map formation in proprioceptive cortex.

Current understanding of feature maps in proprioceptive cortex is quite limited. To complement experimental studies, we developed a computational model of map formation in proprioceptive cortex. Muscle length and tension from six muscle groups controlling the position of a model arm in three-dimensional space served as input to the simulated cortex. The resultant feature map consisted of regularly spaced clusters of cortical columns representing individual muscle lengths and tensions. Cortical units became tuned to plausible combinations of tension and length, and multiple representations of each muscle group were present. The map was organized such that compact regions within which all muscle group lengths and tensions are represented could be identified. Most striking was the observation that, although not explicitly present in the input, the cortical map developed a representation of the three-dimensional space in which the arm moved. These findings represent testable predictions about proprioceptive cortex, and may also help clarify some organizational issues concerning primary motor cortex.

Arm↗
PubMed1987

The period of susceptibility of visual cortical binocularity to unilateral proprioceptive deafferentation of extraocular muscles.

1. The electrophysiological effects of section of extraocular muscle proprioceptive afferents have been investigated in kitten area 17. Extraocular proprioceptive afferents were interrupted by cutting the ophthalmic branch of the fifth trigeminal nerve (V1 nerve) unilaterally in 15 normally reared kittens (NR) between 3 and 12 wk postnatal, in 3 NR adult cats, and in 7 dark-reared (DR) kittens at 6 wk postnatal. Bilateral sections of the V1 nerve were performed in two kittens at 6 wk postnatal. NR kittens were maintained in a normal environment after the section. DR kittens were returned to the darkroom until the recording session. Receptive-field properties of area 17 neurons were studied after a postsurgical delay of 4-7 wk in most NR kittens and of 4 days to 5 wk in DR kittens. In one NR kitten and in the operated adult cats, the delay was 1-2.5 yr. This study is based on a total sample of 1,190 visual cortical units. 2. When performed in NR kittens between 4 and 8 wk of age, the unilateral section of extraocular proprioceptive afferents significantly reduced the proportion of binocular cells: 1 mo after the section of the V1 nerve, half of the visual cortical cells were monocularly activated. A similar reduction in the proportion of binocular cells was also observed in DR kittens operated at 6 wk of age and then maintained in the dark for 5-7 wk. In contrast to the unilateral section, the bilateral section of the V1 nerve performed in 6-wk-old NR kittens did not disrupt cortical binocularity. 3. In 10 of the 22 kittens that had undergone unilateral sections, there was a strong asymmetry in the ocular dominance distribution in favor of one eye. This asymmetry was not related to the side of the section and was the same in both hemispheres for a given kitten. 4. The postsurgical delay played an important role in the appearance of the cortical deficit: binocularity loss was not found within the week following the section but was present 1 mo after the section. This functional impairment appeared to be permanent, since it was still observed 2.5 yr after the section. 5. Cortical cells were classified in two ways on the basis of their receptive-field organization: 1) into S- or C-types (38, 73), and 2) into small area slow (SAS), large area slow (LAS), or Fast (F)-types (42, 57).(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1989

The contribution of articular receptors to proprioception with the fingers in humans.

1. Whether joint receptors contribute demonstrably to proprioception has remained uncertain. Therefore, we tested whether an articular contribution to movement sense could be revealed if the total sensory input available to signal joint movement were reduced by eliminating movement signals from muscles. With a reduced sensory input, whatever contribution articular receptors made to proprioception ought to assume a greater-than-normal importance, and any effect of eliminating articular inputs should become more apparent. The distal interphalangeal joint of the middle finger was used, because the muscles could be decoupled from this joint by positioning the fingers to slacken the tendons. 2. To further enhance the possibility for observing an effect of eliminating articular contributions, we planned to test movement sense at positions of the joint in which the articular receptors would be most active. However, the response properties of receptors in primate finger joints were unknown, so we examined activity of receptors in finger joints of monkeys prior to testing humans. 3. Activity of receptors in interphalangeal joints of monkeys was measured over a wide range of positions before and during local anesthesia of the joint. Little response was seen over intermediate positions, but activity increased as the joint approached full flexion or full extension in much the same manner as responses previously observed with receptors in the knee, elbow, wrist, and hip joints. Local anesthetic injected into the joint space abolished the nerve activity. 4. Proprioception was tested in humans before and during local anesthesia of the joint using a movement-detection paradigm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Behavior of human muscle receptors when reliant on proprioceptive feedback during standing.

1. This study investigated the muscle-spindle discharge from the pretibial flexor muscles of standing human subjects while they performed maneuvers that altered their reliance on proprioceptive feedback to control balance. Single-unit recordings were made from 100 identified muscle afferents, 81 from muscle-spindle endings and 19 from Golgi tendon organs. 2. With 49 spindle endings the subjects stood on a horizontal platform and with 32, on a platform tilted in dorsiflexion (4 degrees) to ensure that the pretibial muscles were active to maintain balance. When standing freely on a horizontal platform without support or vision, there was little or no electromyographic (EMG) activity in the pretibial muscles, and spindle discharge rates were low (55% active; mean rate for all 49 endings, 4.1 Hz). When standing similarly on the tilted platform, 69% of the spindle afferents were active, and the mean discharge rate was 5.4 Hz. The greater number of actively discharging spindle afferents and the preservation of mean discharge rate despite muscle shortening indicates that the pretibial muscles are subjected to increased fusimotor drive when they are tonically active to maintain balance. 3. The effects of small degrees of body sway induced voluntarily or by an external stimulus were studied with 41 afferents (29 spindles; 12 tendon organs). Activation of the pretibial muscles to compensate for backward sway was accompanied by a spindle discharge that usually exceeded the discharge produced by comparable passive movement. This indicates that the pretibial muscles are subjected to increased fusimotor drive when they are phasically active to maintain balance. 4. To vary the reliance placed on the feedback from proprioceptive inputs, the subjects abruptly opened and shut their eyes, took and released support, or tilted their heads. There were no detectable changes in afferent activity unless the maneuver produced a change in EMG activity in the pretibial muscles and/or body sway. Thirty afferents (26 of 46 spindles; 4 of 7 tendon organs) underwent a change in discharge rate associated with a transient change in posture, as recorded by the force platform, or a change in EMG activity in the receptor-bearing muscle. The discharge pattern of 23 afferents did not show any clear change with these maneuvers. 5. It is concluded that maneuvers that increase the reliance on proprioceptive feedback when subjects are standing quietly do not significantly alter the fusimotor drive to the pretibial muscles in the absence of muscle contraction.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Proprioceptive coordination of movement sequences: discrimination of joint angle versus angular distance.

1. The purpose of these experiments was to determine the accuracy with which human subjects could discriminate proprioceptive (nonretinotopic) targets during movement. The targets were located at either a specified angle in joint space, or a specified angular distance from an initial joint angle. 2. In these experiments the right elbows of normal human subjects were passively extended from either predictable or unpredictable starting angles. The subjects were instructed to open the right hand to indicate that the elbow was passing through a target joint angle or a target angular distance. The subjects were not given visual information about the location of the elbow, so they had to rely on proprioceptive input to perform this task. The target (criterion joint angle or angular distance) was learned by the use of proprioception during 8-15 practice trials. 3. Four experiments were conducted. In three experiments the target was located at a constant joint angle, and in the fourth experiment the target was located at a constant angular distance from the starting angle. The starting angle in all four experiments was pseudorandomly varied from trial to trial. 4. On the basis of an analysis of constant errors, subjects were more accurate at discriminating angular distance than joint angle. The slope of the relationship between the starting position and the constant errors was dictated by the task requirement. 5. In the distance discrimination experiment, when the starting angle was more flexed than the intermediate (i.e., central) position, the subjects slightly overshot the target distance. Conversely, when the starting angle was more extended than the intermediate position, the subjects slightly undershot the target distance. 6. In the joint angle discrimination experiments, the opposite results were obtained. Subjects overshot the target when the starting position of the elbow was more extended than the intermediate starting position, and they undershot the target when the starting position was more flexed than the intermediate starting position. The amplitude of these systematic errors increased when the subjects were unaware that the initial angle of their elbow was variable. 7. It is concluded that, in kinesthetic tasks of this type, the discrimination of angular distance is more accurate than the discrimination of joint angle. We hypothesize that the nervous system extracts kinematic information related to both joint angle and angular distance from proprioceptors, and that the encoding and or decoding of angular distance is more accurate than that of absolute joint angle.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Vectorial coding of movement: vision, proprioception, or both?

1. Subjects were asked to point toward visual targets without visual reafference from the moving hand in two conditions. In both conditions the pointing fingertip was viewed only before movement onset. 2. In one condition, the pointing fingertip was viewed through prisms that created a visual displacement without altering the view of the target. In another experimental condition, vision of the fingertip was not displaced. Comparison of these two conditions showed that virtually shifting finger position before movement through prisms induced a pointing bias in the direction opposite to the shift. The extent of this pointing bias was about one third of the prismatic shift applied to the fingertip. 3. Analysis of movement initial direction demonstrated that it was also less deviated than predicted from the prismatic shift. In addition, the reaction time and movement time of the reaching movement were increased. 4. This result is interpreted in the framework of the vectorial coding of reaching movement. Proprioception and vision provide two possible sources of information about initial hand position, i.e., the origin of the movement vector. The question remains as to how these two sources of information interact in specifying initial hand position when they are simultaneously available. 5. Our results are thus discussed with respect to a visual-to-visual movement vector hypothesis and a proprioceptive-to-visual vector hypothesis. It is argued that the origin of the putative movement vector is encoded by weighted fusion of the visual and the proprioceptive information about hand initial position.

Adult↗
PubMed1995

Proprioceptive consequences of tendon vibration during movement.

1. Previous studies have used tendon vibration to investigate kinesthetic illusions in the isometric limb and end point control in the moving limb. These previous studies have shown that vibration distorts the perceptions of static joint angle and movement and causes systematic errors in the end point of movement. In this paper we describe the effects of tendon vibration during movement while human subjects performed a proprioceptively coordinated motor task. In an earlier study we showed that the CNS coordinates this motor task-a movement sequence-with proprioceptive information related to the dynamic position and velocity of the limb. 2. When performing this movement sequence, each subject sat at a table and opened the right hand as the right elbow was passively rotated in the extension direction through a prescribed target angle. Vision of the arm was prevented, and the movement velocity was changed randomly from trial to trial, leaving proprioception as the only useful source of kinematic information with which to perform the task. 3. In randomly occurring trials, vibration was applied to the tendon of the biceps brachii, a muscle that lengthens during elbow extension. In some experiments the timing of tendon vibration was varied with respect to the onset of elbow rotation, and in other experiments the frequency of vibration was varied. In each experiment we compared the accuracy of the subject's response (i.e., the elbow angle at which the subject opened the hand) in trials with tendon vibration with the accuracy in trials without tendon vibration. 4. The effect of tendon vibration depended on the frequency of vibration. When the biceps tendon was vibrated at 20 Hz, subjects opened the hand after the elbow passed through the target angle ("overshooting"). Overshooting is consistent with an underestimate of the actual displacement or velocity of the elbow. Vibration at 30 Hz had little or no effect on the elbow angle at hand opening. Vibration at 40 Hz caused subjects to open the hand before the elbow reached the target angle ("undershooting"). Undershooting is consistent with an overestimate of the actual displacement or velocity of the elbow. The size of the error depended on the velocity of the passively imposed elbow rotation. 5. The effect of tendon vibration also depended on the timing of vibration. If 40-Hz vibration began at the onset of movement, the subject undershot the target. If 40-Hz vibration started 5 s before movement onset and continued throughout the movement, the undershoot error increased in magnitude. However, if 40-Hz vibration started 5 s before movement onset and then stopped at movement onset, the subject overshot the target. When vibration was shut off during movement, a transition occurred from an over-shooting error to an undershooting error at a time that depended on the velocity of elbow rotation. 6. In a separate experiment, subjects were instructed to match either the perceived dynamic position or the perceived velocity of rotation imposed on the right elbow by actively rotating the left elbow. In both matching tasks, tendon vibration produced oppositely directed errors depending on the frequency of vibration. Vibration at 20 Hz produced a perception of decreased elbow velocity and a bias in dynamic position in the flexion direction, and vibration at 40 Hz produced the opposite perceptions. 7. We conclude that muscle spindle afferents, which are activated by tendon vibration, are an important source of the dynamic position and velocity information that the CNS uses to coordinate this movement sequence task. The observed effects of vibration timing and frequency suggest that perceptual changes evoked by vibration cannot be explained by the simple summation of sensory input evoked by movement and by vibration. Rather, the bias in perception produced by vibration appears to be related to the difference between vibration- and movement-evoked activity in muscle spindle afferents.

Adult↗
PubMed1995

Perception of passive whole-body rotations in the absence of neck and body proprioception.

1. This study investigated whether accurate perception of body rotation after passive horizontal whole-body rotations in the dark requires the integration of both vestibular and neck-body proprioceptive signals. 2. In the first experiment, the gain of the vestibuloocular reflex (VOR) of normal subjects ("controls") and of a patient without proprioception of the neck and body muscles was assessed by the use of pulse and sinusoidal stimulation. In the second experiment, the subjects reported verbally the magnitude of the body rotations. Finally, in the third experiment, they shifted gaze to the position fixated before the rotation ("vestibular memory-contingent saccades" paradigm). 3. The VOR gain of the patient was similar to that of controls, although the body rotations of the patient were largely overestimated, regardless of whether the patient reported the perceived magnitude verbally or through a gaze shift toward the position gazed at before the rotation. 4. These results suggest that neck muscle proprioception contributes to the vestibular signal calibration at the perceptual level necessary for determining body orientation accurately after rotations in the dark.

Afferent Pathways↗