From balance regulation to body orientation: two goals for muscle proprioceptive information processing?

This study was based on the assumption that the central processing of proprioceptive inputs that arise from numerous muscles contributes to both awareness and control of body posture. The muscle-spindle inputs form a "proprioceptive chain" which functionally links the eye muscles to the foot muscles. Here, we focused on the specific contribution of two links in the control of human erect posture by investigating how proprioceptive messages arising from ankle and neck muscles may be integrated by the central nervous system. Single or combined mechanical vibrations were applied to different muscle tendons at either one (ankle or neck) or both (ankle plus neck) body levels. The amplitude and the specific direction of the resulting oriented body tilts were analyzed by recording the center of foot pressure (CoP) through a force platform with four strain gauges. The results can be summarized as follows: (1) the vibration-induced whole-body tilts were oriented according to the muscles stimulated; furthermore, the tilts were in opposite directions when neck or ankle muscles on the same side of the body were stimulated; (2) except for the ankle antagonist muscles, co-vibrating adjacent or antagonist muscles at the same body level (ankle or neck) resulted in body sways, whose orientation was a combination of those obtained by stimulating these muscles separately; and (3) likewise, co-vibrating ankle and neck muscles induced whole-body postural responses, whose direction and amplitude were a combination of those obtained by separate vibration. We conclude that the multiple proprioceptive inputs originating from either one or both body levels may be co-processed in terms of vector-addition laws. Moreover, we propose that proprioceptive information from ankle and neck muscles may be used for two tasks: balance control and body orientation, with central integration of both tasks.     

A threshold and continuum of injury during active stretch of rabbit skeletal muscle

Play fighting by juvenile rats involves playful attacks directed at the partner's nape, where successful contact leads to gentle rubbing of the snout into the nape area. In addition, the recipient of such contact may defend the nape by adopting tactics of playful defense. The two most common defensive tactics in the juvenile period are evasion, where the recipient swerves or leaps away and facing defense involving rotation to supine, where the attacker is faced and its further attempts to contact the nape are blocked. An unresolved issue is whether the nape contact itself or defense by the recipient alone or in combination with nape contact, are involved in rewarding play fighting. In this study, drug-induced non-playful partners were used to test the 'motivation' for play fighting when only playful nape contact was possible. In drug-trials compared to baseline and saline trials, both neonatally androgenized females (high players) and control, oil-treated, females (low players), decreased the frequency of launching nape attacks. These results suggest that nape contact alone, in the absence of defense by the recipient, is not sufficient reinforcement for such playful activity, irrespective of the initial playfulness of the subjects. However, while nape attacks decrease, other forms of social contact, such as anogenital investigation and climbing over the partner (i.e., crawl overs), increase in frequency. These results suggest that non-playful partners are not neutral targets for normal rats. Rather, the 'non-normal' behavior of the drugged target may affect the subjects' behavior in such a way as to reduce their playfulness for reasons other than reduced reinforcement for play.     

Passive sustained turning of the head induces asymmetric gain of the vestibulo-ocular reflex in healthy subjects

In order to test the hypothesis of an interaction between neck proprioception and the vestibulo-ocular reflex (VOR), we rotated 16 healthy subjects both facing forward and with their heads passively turned 70 degrees to either side. We found that gain tended to be lower when the subjects were rotated with their heads turned opposite to the direction of rotation compared to when they were rotated in the same direction, but facing forward. Although our findings were not statistically significant, they suggest that there is a measurable interaction between neck proprioception and the VOR in subjects with normal vestibular function. Asymmetric neck muscle proprioceptive signals seem to give rise to asymmetric functioning of the VOR, which, at least in part, could be the pathogenesis of cervical dizziness. If so, this could lead to misinterpretation of vestibular assessments in patients with neck pain who also complain of dizziness.     

Eye movements evoked by proprioceptive stimulation along the body axis in humans

Proprioceptive input arising from torsional body movements elicits small reflexive eye movements. The functional relevance of these eye movements is still unknown so far. We evaluated their slow components as a function of stimulus frequency and velocity. The horizontal eye movements of seven adult subjects were recorded using an infrared device, while horizontal rotations were applied at three segmental levels of the body [i.e., between head and shoulders (neck stimulus), shoulders and pelvis (trunk stimulus), and pelvis and feet (leg stimulus)]. The following results were obtained: (1) Sinusoidal leg stimulation evoked an eye response with the slow component in the direction of the movement of the feet, while the response to trunk and neck stimulation was oriented in the opposite direction (i.e., in that of the head). (2) In contrast, the gain behavior of all three responses was similar, with very low gain at mid- to high frequencies (tested up to 0.4 Hz) but increasing gain at low frequencies (down to 0.0125 Hz). We show that this gain behavior is mainly due to a gain nonlinearity for low angular velocities. (3) The responses were compatible with linear summation when an interaction series was tested in which the leg stimulus was combined with a vestibular stimulus. (4) There was good correspondence of the median gain curves when eye responses were compared with psychophysical responses (perceived body rotation in space; additionally recorded in the interaction series). However, correlation of gain values on a single-trial basis was poor. (5) During transient neck stimulation (smoothed position ramp), the neck response noticeably consisted of two components -- an initial head-directed eye shift (phasic component) followed by a shift in the opposite direction (compensatory tonic component). Both leg and neck responses can be described by one simple, dynamic model. In the model the proprioceptive input is fed into the gaze network via two pathways which differ in their dynamics and directional sign. The model simulates either leg or neck responses by selecting an appropriate weight for the gain of one of the pathways (phasic component). The interaction results can also be simulated when a vestibular path is added. This model has similarities to one we recently proposed for human self-motion perception and postural control. A major difference, though, is that the proprioceptive input to the gaze-stabilizing network is weak (restricted to low velocities), unlike that used for perception and postural control. We hold that the former undergoes involution during ontogenesis, as subjects depend on the functionally more appropriate vestibulo-ocular reflex. Yet, the weak proprioceptive eye responses that remain may have some functional relevance. Their tonic component tends to stabilize the eyes by slowly shifting them toward the primary head position relative to the body support. This applies solely to the earth-horizontal plane in which the vestibular signal has no static sensitivity.     

Cervicocephalic kinesthetic sensibility, active range of cervical motion, and oculomotor function in patients with whiplash injury

OBJECTIVE: To investigate cervicocephalic kinesthetic sensibility, active range of cervical motion, and oculomotor function in patients with whiplash injury. DESIGN: A 2-year review of consecutive patients admitted to the emergency unit after whiplash injury. SETTING: An otorhinolaryngology department. PATIENTS AND SUBJECTS: Twenty-seven consecutive patients with diagnosed whiplash injury (14 men and 13 women, mean age, 33.8yrs [range, 18 to 66yrs]). The controls were healthy subjects without a history of whiplash injury. MAIN OUTCOME MEASURES: Oculomotor function was tested at 2 months and at 2 years after whiplash injury. The ability to appreciate both movement and head position was studied. Active range of cervical motion was measured. Subjective intensity of neck pain and major medical symptoms were recorded. RESULTS: Active head repositioning was significantly less precise in the whiplash subjects than in the control group. Failures in oculomotor functions were observed in 62% of subjects. Significant correlations occurred between smooth pursuit tests and active cervical range of motion. Correlations also were established between the oculomotor test and the kinesthetic sensibility test. CONCLUSION: The results suggest that restricted cervical movements and changes in the quality of proprioceptive information from the cervical spine region affect voluntary eye movements. A flexion/extension injury to the neck may result in dysfunction of the proprioceptive system. Oculomotor dysfunction after neck trauma might be related to cervical afferent input disturbances.     

Disturbed eye movements after whiplash due to injuries to the posture control system

Self-reports after whiplash often indicate associations with vertigo and reading problems. Neuropsychological and otoneurological tests were applied to a group of whiplash patients (n = 26) and to a carefully matched control group. The whiplash group deviated from the control group on measures of eye movements during reading, on smooth pursuit eye movements with the head in normal position, and with the body turned to the left or to the right. Clinical, caloric, and neurophysiological tests showed no injury to the vestibular system or to the CNS. Test results suggest that injuries to the neck due to whiplash can cause distortion of the posture control system as a result of disorganized neck proprioceptive activity.     

Medullary carcinoma of the thyroid

Medullary carcinoma is an unusual malignant neoplasm. The cell of origin is considered to be the C-cell which is derived from the ultimobranchial body and neural crest. The tumor is solid and has characteristic amyloid in the stroma. The lesion usually presents as a neck mass, and multicentricity is not unusual. In some patients diarrhea may be an important presenting symptom. Serum calcitonin is typically elevated and is important in the diagnostic confirmation. About 10 percent of the cases are part of a familial endocrine syndrome which includes pheochromocytomas, mucosal neuromas, and other endocrine gland adenomas. Frequent multicentricity and early cervical lymphatic and systemic metastases necessitate total thyroidectomy and radical neck dissection. Prognosis varies from a rapid demise to long term survival.     

Bilateral subclavian steal syndrome

Two cases of bilateral subclavian steal syndrome are presented, demonstrating complete occlusion at the origin of both subclavian arteries with distal reconstitution via reversal of blood flow through the vertebrobasilar system. Since unsuspected subclavian artery obstruction may present significant angiographic hazard, careful physical examination including blood pressures in both upper extremities and auscultation of the neck is necessary in order to avoid undesirable complications.     

Intractable diarrhea in a boy with vasoactive intestinal peptide-producing ganglioneuroblastoma

A 1-year-old boy had intractable diarrhea and symptoms of the watery-diarrhea-hypokalemia-achlorhydria (WDHA) syndrome, a well-known entity in adults. Resection of a ganglioneuroblastoma situated in the neck caused prompt relief of symptoms. The ganglioneuroblastoma in this instance contained the enterohormone vasoactive intestinal peptide (VIP); blood levels of this peptide were elevated preoperatively. After tumor resection, the VIP level returned to normal, and the diarrhea ceased on the day of the operation. The genesis of the diarrhea in relation to the production of polypeptides from neuroendocrine origin is discussed (APUD-cell concept). VIP may be the mediator of the WHDA syndrome in ganglioneuroblastoma.     

Changes in dorsal neck muscle activity related to imposed eye movement in the decerebrate pigeon

Movements of the head and eyes are known to be intimately related. Eye position has also been shown to be closely related to the electromyographic activity of dorsal neck muscles; however, extraocular muscle proprioception has not generally been considered to play a part in the control of such movements. We have previously shown that, in the pigeon, imposed movements of one eye modify the vestibular responses of several dorsal neck muscles in ways that are dependent on stimulus parameters such as the amplitude and velocity of imposed eye movement. The present study examines more closely the interactions between imposed eye movements and different muscle pairs. The three neck muscle pairs studied each responded to afferent signals from the extraocular muscles in discrete and specific ways which appeared to be correlated with their different actions. Complementary effects of imposed eye movements in the horizontal plane were seen for both the complexus and splenius muscle pairs, with imposed eye movements in one direction producing the largest inhibition of the ipsilateral muscle's vestibular response and imposed eye movements in the opposite direction the largest inhibition of the contralateral muscle's vestibular response. During roll tilt oscillation (ear-up/ear-down) in the frontal plane, similar complementary effects of imposed eye movement were seen in the complexus muscle pair, but the splenius muscle pair showed little tuning, with similar inhibition for imposed eye movement directed either upwards or downwards. In contrast to these complementary effects, the biventer cervicis muscle pair showed no vestibular modulation during vestibular stimulation in the horizontal plane and their spontaneous activity was not altered by imposed eye movement. During roll-tilt oscillation (ear-up/ear-down) in the frontal plane imposed eye movement directed vertically upwards increased both muscles' vestibular responses and imposed eye movement directed vertically downwards inhibited both muscles' vestibular responses. Section of the ophthalmic branch of the trigeminal nerve (deafferenting the eye muscles) abolished the effects of imposed eye movement on the neck muscle pairs. In conjunction with further control experiments these results provide compelling evidence that proprioceptive signals from the extraocular muscles reach the neck muscles and provide them with a functionally significant signal. We have previously shown that signals from the extraocular muscles appear to be involved in the control of the vestibulo-ocular reflex. It follows from the experiments reported here that proprioceptive signals from the extraocular muscles are also likely to be involved in the control of gaze.     

Unilateral posterior spinal artery syndrome of the upper cervical cord associated with vertebral artery occlusion

Upper cervical cord infarction in the territory of the posterior spinal artery is very rare. We present here an elderly man who developed right upper cervical (C1-2) posterior spinal artery syndrome associated with vertebral artery occlusion. A 62-year-old man suffered a right upper cervical (C1-2) posterior spinal artery syndrome. The onset was associated with neck flexion. Magnetic resonance imaging clearly showed an ischemic lesion. Cerebral angiography revealed occlusion of the distal end of an ipsilateral vertebral artery. The occlusion of the vertebral artery probably caused the cervical cord infarction. The neck flexion possibly induced thrombogenesis in the vertebral artery. Unilateral upper cervical posterior spinal artery syndrome associated with vertebral occlusion following neck flexion was suggested.     

Treatment of atypical autism in Martin-Bell syndrome

The paper reports the case of sibs, brother and sister, with Martin-Bell's syndrome confirmed cytogenetically. Mental retardation and autism were the main phenomena in the clinical picture. Positive effect was achieved by means of Skvortsov--Osipenko method (metameric injection of cerebral hydrolysates' preparations, stimulation of visual, acoustic and proprioceptive analyzers). A decline of the signs of intellectual retardation and autism were observed in both children.     

Lupus vulgaris complicated by metastatic squamous cell carcinoma

A 47-year-old Bedouin man presented with an ulcerated nodule of several months' duration on the nape of the neck. The nodule developed on an asymptomatic, slowly growing plaque which appeared during childhood. Physical examination revealed two erythematous plaques covering the posterior and right lateral aspects of the neck. The border of the plaques was soft, circinate, with a reddish-brown color, while the center was slightly erythematous and atrophic. An ulcerated nodule measuring 2 cm was seen on one of the plaques. Physical examination was unremarkable with no lymphadenopathy. Laboratory tests, including complete blood cell count, erythrocyte sedimentation rate (ESR), and routine chemistry tests, were all within normal limits. Chest X-ray showed a small calcified perihilar lymph node. The Mantoux test was positive with erythema and induration of 15 mm after 48 h. Biopsy from a plaque showed extensive diffuse granulomatous infiltration throughout the dermis with epithelioid and Langhans giant cells surrounded by mononuclear inflammatory cells. No caseation necrosis was present. Ziehl-Neelsen, periodic acid-Schiff (PAS), and Giemsa stains were negative. Polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis and atypical mycobacteria from a skin sample was also negative. Fresh tissue cultures yielded M. tuberculosis after 6 weeks. A biopsy specimen from the ulcerated nodule demonstrated islands of atypical malignant squamous cells invading the dermis, which were compatible with moderately differentiated squamous cell carcinoma (SCC). The ulcerated nodule was completely excised, and treatment for tuberculosis was initiated with a combination of isoniazid, rifampicin, and pyrazinamide. Within 3 months of therapy, the patient's lesions resolved, leaving only slightly atrophic hypopigmented scars. A month after the treatment's initiation, an enlarged cervical lymph node was noted showing metastatic SCC on histologic examination. The patient underwent neck dissection and radiation therapy without evidence of any further metastases.     

Uptake and intracellular distribution of 4-aminofluorescin-labelled poly(L-lysine citramide imide) in K562 cells

This paper proposes a new self-organizing, biologically-inspired control architecture for mobile robots consisting of a controller and a value system. The controller uses activity patterns of visual sensors to determine the motor commands, whereas the value system receives stimuli from proprioceptive sensors. This design decision is justified by the following arguments: (1) the feedback of proprioceptive sensory patterns is omnipresent in biological systems and has been widely neglected in control systems, (2) both components are significantly decoupled by using different sensory modalities, and (3) proprioceptive sensors operate more reliably and can be used more efficiently than visual sensors, such as pixels in a CCD camera. Practical experiments with the Khepera robot show that by using proprioceptive sensor values, the control architecture can adapt to different environments and yield very robust behavior with respect to, for example, sensor failures. Furthermore, the new control architecture can be easily enhanced by further components.     

Perianal hidradenitis suppurativa: early surgical treatment gives good results in chronic or recurrent cases

Hidradenitis suppurativa (HS) represents a chronic, recurrent, deep-seated folliculitis resulting in abscesses followed by the formation of sinus tracts and scarring. It is an uncommon disorder frequently involving the perianal region. We review the clinical and pathological features of 12 patients (10 men and two women) with perianal HS (PHS). The mean age at presentation was 43 years (range 24-65), and the mean duration of illness was 14 years (range 2-30). Two patients exhibited multiple areas of involvement, including the axilla and the nape of the neck, in addition to the perianal region. Histological examinations showed epidermis-lined sinuses surrounded by dense plasma cell infiltration in four of nine specimens. The complications related with PHS included anal fistula (seven patients), diabetes mellitus (four), malignant tumour (two) and sepsis (one). Three patients died of the complications. Eight patients underwent wide local excision. The defects were managed with a meshed split-thickness skin graft in five patients, and open treatment in the remainder. New lesions developed in untreated skin of two patients. However, no patient relapsed in the surgically treated sites. PHS is frequently complicated with anal fistula and is occasionally life-threatening as a result of the occurrence of malignant tumours or sepsis. Early surgical excision followed by meshed split-thickness skin graft can successfully cure the lesion without functional disturbance.     

Proprioception versus motor outflow in timing: A reply to Jones.

Discusses B. Jones's (see record 1973-20006-001) argument that the motor outflow hypothesis should be considered a rival to the proprioceptive feedback interpretation of the motor response timing data reviewed by Schmidt. However, with no data ruling in favor of motor outflow over proprioceptive feedback for timing, and with other peripheral feedback channels (e.g., vision) known to be mechanisms for timing, the proprioceptive feedback explanation is favored over motor outflow. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

LAP-1 cold preservation solution for isolation of high-quality human pancreatic islets

The purpose of this study was to determine the precision of proprioceptive localization of the hand in humans. We derived spatial probability distributions which describe the precision of localization on the basis of three different sources of information: proprioceptive information about the left hand, proprioceptive information about the right hand, and visual information. In the experiment subjects were seated at a table and had to perform three different position-matching tasks. In each task, the position of a target and the position of an indicator were available in a different combination of two of these three sources of information. From the spatial distributions of indicated positions in these three conditions, we derived spatial probability distributions for proprioceptive localization of the two hands and for visual localization. For proprioception we found that localization in the radial direction with respect to the shoulder is more precise than localization in the azimuthal direction. The distributions for proprioceptive localization also suggest that hand positions closer to the shoulder are localized more precisely than positions further away. These patterns can be understood from the geometry of the arm. In addition, the variability in the indicated positions suggests that the shoulder and elbow angles are known to the central nervous system with a precision of 0.6-1.1 degrees. This is a considerably better precision than the values reported in studies on perception of these angles. This implies that joint angles, or quantities equivalent to them, are represented in the central nervous system more precisely than they are consciously perceived. For visual localization we found that localization in the azimuthal direction with respect to the cyclopean eye is more precise than localization in the radial direction. The precision of the perception of visual direction is of the order of 0.2-0.6 degrees.     

The arterial supply of the urinary bladder

(1) The urachal artery has a primary origin from the umbilical artery itself, and is at first bilateral. (2) The arterial pattern in newborn infants is not identical to that of adults. Obliteration of the umbilical artery in older infants carries with it obliteration of some of its branches, especially at their origin from its distal part, with a resulting change in arterial pattern. (3) The middle vesicle artery is a fairly constant branch of the umbilical artery, supplying the bladder neck and the front of the bladder above the neck. (4) The urachal and middle vesicle arteries, when unilateral, occur with equal frequency on both sides. (5) The anastomosis between superior vesical and inferior episgastric arteries was confirmed in the subperitoneal tissues, but was very rare in the wall of the bladder, occurring only when an abnormal obturator artery was the source of a superior vesical branch. (6) The constancy of the vesiculo-deferential artery is confirmed.     

Selective shunting with EEG monitoring is safer than routine shunting for carotid endarterectomy

The muscular and skeletal systems of the long neck were morphologically examined in order to clarify their modification and their functional significance in the giraffe (Giraffa camelopardalis). The longissimus, the thoracic and cervical, spinalis and semispinalis, the cranial and caudal head oblique, and the multifidus muscles, and the nuchal ligament were observed at their origin and insertion. The atlas, axis, and the third cervical vertebra were measured and examined. The modified spinous processes provided the large attachment surface for the strong nuchal ligament and for the muscles of the axis and other cervical vertebrae, while the muscle tendons had their origin in the ventrocaudally-enlarged transverse process. It is concluded that the modified muscles with their expanded belly and tendon have the functions of occupying the interspace among long vertebrae, and also of supporting the head and neck by means of their wide attachment to the altered vertebral processes.     

Scleredema, acanthosis nigricans and IgA/Kappa multiple myeloma

BACKGROUND: Scleredema is an uncommon disease of unknown origin. Characteristic thick skin with symmetrical diffuse induration develops. The infiltration begins on the face and neck then extends to the root of the upper limbs and trunk. There are three clinical types of scleredema. The first is preceded by an upper airway infection and progresses rapidly before regressing spontaneously within a few months. The second type is associated with chronic diabetes. The third type is associated with monoclonal gammapathy, rarely of myelomatous type, and develops insidiously. Acanthosis nigricans can be a paraneoplastic syndrome, often associated with a gastrointestinal cancer. Few cases associating scleredema and acanathosis nigricans have been reported. CASE REPORT: A 56-year old woman had developed scleredema over the last 6 years when acanthosis nigricans appeared together with IgA kappa multiple myeloma. Treatment with melphalan and prednisolone was effective against the myeloma as well as the scleredema and acanthosis nigricans. DISCUSSION: Only five cases of associated scleredema and multiple myeloma have been reported, four with kappa IgG myeloma and one with IgA myeloma. An association between acanthosis nigricans and sclerederma could be coincidental although the fact that the different manifestations regressed together after the myeloma treatment would suggest some relationship between these three diseases.