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PubMed1980

The effects of reserpine on motor activity and pallidal discharge in monkeys: implications for the genesis of akinesia.

1. A reversible disturbance of basal ganglia function was produced in monkeys by the intramuscular administration of reserpine.2. Pallidal discharge was then compared with that recorded in the same animals during movement performance and following passive manipulation of the limbs.3. Akinesia, loss of postural support of the trunk, head and neck and absent postural reflexes were the predominant motor abnormalities produced by reserpine administration.4. Occasionally, postural tremor and catatonia were apparent. Rigidity and resting tremor were absent.5. Recordings made in the pallidum during the presence of akinesia revealed a marked reduction in natural neuronal discharge.6. Some pallidal neurones that remained active were driven in an uncharacteristic manner by peripherally generated afferent inputs from wide territories and by a variety of peripheral stimuli.7. The findings suggest the hypothesis that the akinesia in these animals was due to the diminished pallidal activity, and that pallidal discharge is normally a prerequisite for the performance of spontaneous motor activity. Pallidal neuronal firing may provide a background excitability to motor regions involved in the maintenance and elaboration of natural motor activity.

Action Potentials↗
PubMed1992

Abdominal postural motor responses initiated by the muscle receptor organ in lobster depend upon centrally generated motor activity.

1. Stretch stimulation of the abdominal muscle receptor organ of the lobster Homarus americanus initiated spike discharge of its tonic sensory neuron (SR1). This sensory response evoked a series of tonic postural reflex responses in the motor neurons that innervate the superficial extensor and flexor muscles of the abdominal postural system. The type of motor response depended on whether a flexion or extension pattern of spontaneous activity was being generated by the postural efferents. Spontaneous shifts between these centrally generated motor activities completely changed the SR1-evoked reflex responses. 2. During spontaneous centrally initiated flexion activity, tonic SR1 neuron discharge elicited an assistance response that included excitation of a medium-sized flexor excitor (f3) and the peripheral extensor inhibitor (e5), and inhibition of at least one extensor excitor. Neither the other flexor excitors nor the peripheral flexor inhibitor (f5) were affected by SR1 excitation. 3. During spontaneous centrally initiated extension activity, SR1 activity elicited a response that included excitation of the extensor excitors and the flexor peripheral inhibitor (f5) only, f3 and e5 spontaneous activities were unchanged. This response was a resistance reflex, since SR1 discharge normally resulted from an imposed abdominal flexion. 4. The SR1-initiated control of postural motor activity in lobster differs from previously published results in the crayfish Procambarus clarkii.

Abdomen↗
PubMed1979

Quantitative analysis of stance in late cortical cerebellar atrophy of the anterior lobe and other forms of cerebellar ataxia.

(1) Methods have been developed to measure, analyse and document postural sway. The main parameters studied were: average sway amplitude; length of the sway path per unit time; sway direction and sway position histograms; and the frequency spectra of the antero-posterior and lateral sway components. (2) Postural ataxia was quantitatively studied in three groups of patients with cerebellar lesions: (a) late atrophy of the anterior lobe, (b) tumours of the cerebellar hemisphere and (c) tumours within the vestibulo-cerebellum. Characteristic differences were found. (3) Patients with anterior lobe lesion show a specific 3 Hz postural tremor in the antero-posterior direction. The tremor can be evoked by sudden destabilization in incipient cases. Less characteristic and smaller in amplitude is a mainly lateral sway component with an average frequency of 0.5 Hz. This is also seen in cases with spinal ataxia. Visual stabilization of posture is frequently preserved. Its amount does not correlate with general instability of posture. Tremor and characteristically exaggerated intersegmental responses between head, trunk, hips and legs are interpreted as the consequence of hyper-excitability of postural reflexes in these patients. (4) Patients with lesions of the hemispheres show only slight postural instability without directional preference. Their sway parameters with eyes open are within the 2 sigma range of normals and there is no significant difference from normals in these parameters even when the eyes are closed. Therefore these patients cannot be distinguished from normals by means of their platform recordings. (5) Two patients with posterior vermal and flocculo-nodular lesions were very unstable without preferred axis or frequency of instability. In contrast to the anterior lobe group the instability was characterized by the absence of intersegmental movements.

Adult↗
PubMed1975

Locomotor prognosis in cerebral palsy.

A study of the prognosis for walking of 73 pre-school children who had cerebral palsy or delayed motor development is reported. The importance of prognostic signs, based upon the presence or absence of postural reflex activity, was confirmed. The prognosis was accurate in 94-5 per cent of the 73 children studied. The method of scoring a child's reflex responses and relating this to the prognosis seems to be a simple procedure, easy to understand and to apply. It is suggested that the assessment of treatment methods should include an analysis of the child's walking potential, based upon the methods delineated in this study, before treatment is started.

Age Factors↗
PubMed1986

Vestibulo-spinal response modification as determined with the H-reflex during the Spacelab-1 flight.

Our laboratory at the Johnson Space Center has employed the H-reflex recorded from the soleus muscle as a method of monosynaptic reflex testing in conjunction with vertical linear acceleration to assess modification of utriculo-saccular function induced through prolonged exposure to microgravity. It was hypothesized that exposure to free fall would reduce the necessity for postural reflexes in the major leg muscles, and that postural modification would reflect a change, not in the peripheral vestibular organs, but more centrally. This postural adjustment would reflect a sensory motor rearrangement where otolith receptor input was reinterpreted to provide an environmentally appropriate response. In addition to the H-reflex (which was the only inflight measurement), vestibulo-spinal EMG from the gastrocnemius, and self-motion reports were obtained in response to a sudden earth vertical fall. Preflight, inflight and postflight motion sickness reports were also recorded, and related to the H-reflex data. The results indicated that early inflight H-reflex amplitude was similar to that recorded preflight, but that measurements obtained later in the flight (day seven) did not show a change in potentiation as a function of the different drop to shock intervals. Immediate postflight H-reflex response in three of the four astronauts tested showed a rebound effect. Postflight gastrocnemius EMG in response to the sudden fall did not show a significant change from preflight values. However, one crewman who was tested early postflight did show an increase in EMG activity in response to the sudden fall. This immediate postflight effect returned to baseline rapidly. Self-motion perception obtained inflight suggested that the early inflight drops were perceived like those preflight. Drops later inflight were described as sudden, fast, hard and translational in nature. Immediately postflight the drops were perceived like those late inflight, and the astronauts said that they did not feel as though they were falling, rather the floor came up to meet them. Post hoc peak H-reflex amplitude, both preflight and postflight was related to inflight space motion sickness.

Humans↗
PubMed1983

Infant lesion effect: II. Sparing and recovery of function after spinal cord damage in newborn and adult cats.

Considerable disagreement exists concerning the degree to which sparing and/or recovery of function occurs following CNS damage at birth rather than in adulthood. To study this question, the spinal cord was hemisected in neonatal and adult cats and the motor behavior of the two groups was compared when the neonatal operates matured and the adult operates recovered. Quantitative analysis of the motor behavior indicated that the effects were not uniform: in some aspects of motor behavior sparing of function was found in neonatal operates; in others, the adult operates displayed performance which was superior to the neonatal group. Both groups exhibited considerable recovery of locomotor function, but adult operates showed greater accuracy of limb placement during locomotion. Furthermore, the neonatal group had some deficits in locomotion and postural reflexes which were not seen at all in adult operates. There were, however, examples of greater recovery in neonatal operates, e.g. in ipsilateral hopping responses and in the reduced hypermetria of the proprioceptive placing reflexes. True sparing of function was manifested by the presence of tactile placing in neonatal operates which was always abolished permanently in adult operates. The characteristics of the performance suggested that although sparing of function had obviously occurred, the response had never matured fully. These results taken together indicate that the relationship between age at the time damage occurs and ultimate outcome in terms of motor behavior is complex: different motor patterns respond differently to the same lesion. True sparing of function may be restricted to motor patterns which are not directly affected by the lesion because they have not yet developed when the lesion is made.

Age Factors↗
PubMed1992

Postural instability in Parkinson's disease.

Postural instability is one of the most disabling features of Parkinson's disease. Many factors contribute to balance impairment of Parkinson patients, including disturbed postural reflexes and poor control of voluntary movement. Additional factors which place Parkinson patients at risk for falls are side-effects of medication (dyskinesias), the poor response of postural instability to antiparkinsonian medication, orthostatic hypotension, gait abnormalities, muscular weakness in leg muscles and superimposed age-related changes such as reduced peripheral sensation. Future studies should not only investigate means of preventing falls in unstable patients, but should also be directed towards development of new treatment. Because accumulating evidence indicates that postural instability is at least partially related to non-dopaminergic lesions, these novel therapeutic approaches should be aimed at overcoming non-dopaminergic neurotransmitter deficiencies.

Humans↗
PubMed1986

Value of physical and pharmacological tests in predicting intrinsic and extrinsic sick sinus syndrome.

We studied 13 patients with sick sinus syndrome using various physical (postural reflex testing. Valsalva manoeuvre, carotid sinus massage), pharmacological (intravenous isoprenaline, atropine, neostigmine and total autonomic blockade) and electrophysiological tests in order to identify simple non-invasive markers of intrinsic sick sinus syndrome. Following autonomic blockade, 6 patients had normal and the remaining 7 had an abnormal intrinsic heart rate. Electrophysiological testing revealed abnormal sinus node parameters in 8 (62%) subjects in the basal state and 11 (85%) after autonomic blockade. Carotid sinus massage was abnormal in all patients (100%) with an abnormal intrinsic heart rate, and in only 2 of the 6 (33%) with normal intrinsic heart rate (P less than 0.05). The heart rate response to isoprenaline was abnormal in 5 of the 6 (83%) patients with normal as compared to only 1 of the 7 with abnormal intrinsic heart rate. With isoprenaline there was a significantly (P less than 0.05) higher increase in heart rate in patients with abnormal as compared to those with normal intrinsic heart rate. The other physical and drug tests were not helpful to differentiate between intrinsic and extrinsic mechanisms. Thus, carotid sinus massage and, to some extent, isoprenaline administration appear simple bedside tests which may be helpful in identifying the underlying mechanism of sick sinus syndrome.

Adult↗
PubMed1990

[Neurological and pathophysiological analyses of patients with absent auditory brainstem evoked response].

Seventeen patients with no auditory brainstem evoked response (ABR) who suffered from various neurological disorders were reported. We evaluated the possibilities of co-existent brainstem lesions in addition to the peripheral impairment in the auditory pathway, by assessing neurological findings and other laboratory examinations, including cranial CT and electrically elicited blink reflex. Patients who showed cranial nerve symptoms other than that of the acoustic nerve or abnormal postural reflexes were suspected to have brainstem dysfunction. It was difficult, however, to exclude the influence from the dysfunction in the more central level CNS. Definite brainstem atrophy was revealed radiologically only in one case who was at the end stage of the degenerative disease. Blink reflex was studied in eleven cases, four of whom revealed abnormal responses, also suggesting brainstem dysfunction. All the five cases, consistent with these abnormal laboratory findings, had shown severe delay in motor development. Other five patients who showed rather good auditory behavior were considered to have 'desynchronization' response to ABR in the auditory pathway at the peripheral level. Many pathophysiological conditions may be involved in the phenomenon of absent ABR, which should be carefully evaluated from the viewpoints of clinical neurology.

Blinking↗
PubMed1992

[A case of progressive supranuclear palsy dramatically improved with L-threo-3,4-dihydroxyphenylserine].

We report a 67-year-old female with progressive supranuclear palsy (PSP) who dramatically improved when given L-threo-3,4-dihydroxyphenylserine (L-DOPS). This patient developed dysarthria, lack of facial expression, and slowness at age 64. She was admitted to a local hospital, diagnosed as having parkinsonism and treated with antiparkinsonian drugs. Despite this treatment, she had difficulty in turning over in bed and standing up from a seat, and began to fall backward at age 65. One year later, she had trouble in walking due to frequent falls and became bedridden. The patient was admitted to our hospital in July 1991 under treatment with 20 mg/200 mg of carbidopa/L-dopa and 4 mg of trihexyphenydyl hydrochloride per day. Neurological examination revealed masked face, pseudobulbar palsy, and dystonic rigidity of the neck and upper trunk. Eye movements were normal except for impaired vertical saccades and convergence inability. Deep tendon reflexes were generally brisk and the plantar responses were flexor bilaterally. Tests of pulsion showed that her postural reflex was markedly disturbed, especially in retropulsion. Her gait showed severe unsteadiness. Neuropsychological tests showed intellectual impairment, frontal lobe dysfunction, and memory disturbance. Computed tomography showed an atrophic midbrain with prominent enlargement of ambient and quadrigeminal plate cisterns. Single photon emission computed tomography (SPECT) using 123-I-isopropyl-iodoamphetamine demonstrated marked frontal hypoperfusion. L-DOPS was administered at a dose of 100 mg per day and gradually increased up to 600 mg per day over a period of five weeks, while carbidopa/L-dopa and trihexyphenidyl hydrochloride were continued as on admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1980

[Pathogenesis of infantile cerebral palsy].

Some causes of the pathological activity of postural reflexes and other motor disturbances underlying the clinical picture of infantile cerebral paralysis are considered. It is shown that disturbed metabolism of corticosteroids observed in that disease, as well as impaired functional activity of T lymphocytes promote the development of both inflammatory and neuroimmune processes in the brain, mainly in large hemispheres--and this may be one of the causes of the pathological postural activity.

Adrenal Cortex Hormones↗
PubMed1983

Follow-up study of children with cerebral coordination disturbance (CCD, Vojta).

713 children (from newborn to 12-month-old) with delayed motor development were carefully examined and classified into normal, very light cerebral coordination disturbance (CCD, Vojta), light CCD, moderate CCD, severe CCD, suspected cerebral palsy (CP) and other diseases at their first visit, and were followed up carefully. Finally, 89.0% of very light CCD, 71.4% of light CCD, 56.0% of moderate CCD and 30.0% of severe CCD developed into normal. 59.5% of moderate CCD and 45.5% of severe CCD among children who were given Vojta's physiotherapy developed into normal. The classification of cases with delayed motor development into very light, light, moderate and severe CCD based on the extent of abnormality in their postural reflexes is useful and well correlated with their prognosis. Treatment by Vojta's method seems to be efficient and helpful for young children with delayed motor development.

Female↗
PubMed1994

Task-dependent reflex responses and movement illusions evoked by galvanic vestibular stimulation in standing humans.

1. To identify the vestibular contribution to human standing, responses in leg muscles evoked by galvanic vestibular stimulation were studied. Step impulses of current were applied between the mastoid processes of normal subjects and the effects on the soleus and tibialis anterior electromyograms (EMGs), ankle torque, and body sway were identified by post-stimulus averaging. The responses were measured when subjects stood on a stable platform or on an unstable platform and the effects of eye closure were also assessed. Responses were also recorded during voluntary contraction of the leg muscles and when subjects balanced a load equivalent to their own body in a situation where vestibular postural reflexes would not be useful. 2. At a mean post-stimulus latency of 56 ms, there were reciprocal changes in soleus and tibialis anterior muscle activity followed, at 105 ms, by larger responses of opposite sign. These were termed the short- and middle-latency responses, respectively. Both responses increased with stimulus intensity, but the short-latency response had a higher threshold. The early response had a similar latency to EMG responses evoked by rapid postural perturbations. Both responses were larger when the eyes were closed, but eye closure was associated with increased sway and EMG activity, and the responses were of similar magnitude when scaled to background EMG level. 3. Both short- and middle-latency EMG responses in soleus and tibialis anterior muscles produced small transient postural sways. The transient changes in EMG activity were followed by a larger prolonged sway which was not attributable to the activity in these muscles but rather to reflex or volitional adjustments to movements at other body segments. When subjects were prevented from swaying, the galvanic stimulus produced illusory movements in the opposite direction to the sway evoked when standing, and it is possible that the prolonged sway is a reaction to the illusion of sway. 4. The short- and middle-latency responses were modified during different postural tasks according to the dependence on vestibular reflexes. When the support platform was unstable, the EMG responses to galvanic stimulation were larger. There were no vestibular-evoked responses when seated subjects made voluntary contractions of the leg muscles or when they stood upright with the trunk supported, using the ankles to balance a body-like load.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1996

Immediate postural responses to total nasal obstruction.

Twenty-five nasal breathing adults were radiographically examined before and after their nasal respiratory pattern had been artificially eliminated for a period of 1 hour. Six angular and six linear variables were measured to determine the extent of the postural reflexive behavior of the cranium, mandible, hyoid bone, tongue, and lips. All subjects coped in their own individual way with the environmental impact. The most generalized findings were parting of the lips (p < 0.05), a drop in mandibular position (p < 0.001), and a downward movement of the hyoid bone (p < 0.05). Cranial extension did not reach statistical significance (p = 0.06). The relevance of these findings relative to primate experiments and human clinical research is discussed. If the same postural reactions are maintained over a long-term period, they may be instrumental in influencing the vertical craniofacial growth pattern.

Adaptation, Physiological↗
PubMed1984

Characteristic alterations of long-loop "reflexes" in patients with Friedreich's disease and late atrophy of the cerebellar anterior lobe.

Sudden tilting of a platform around the axis of the human ankle joint causes a regular pattern of short and medium latency EMG responses in the stretched triceps surae muscle and a long latency response in its antagonist, the anterior tibial muscle. This paper reports alterations of these EMG responses in 41 patients with cerebellar lesions. Patients with anterior lobe atrophy exhibited normal latencies of all EMG responses, but an increase in duration and amplitude of the long latency response. This may at least partially explain the 3 Hz postural tremor, which can be evoked in these patients through a toe-up tilt of the platform. Patients with lesions restricted to the vestibulocerebellum and to the cerebellar hemispheres exhibited normal latencies of all EMG responses. The most specific finding in all of the patients suffering from Friedreich's ataxia (affecting spinal afferents) was the massive delay of the stabilising response of the anterior tibial muscle. The fact that the patients with lesions restricted to the cerebellum invariably exhibited normal latencies of postural "reflexes" indicates that the exact "timing" of these responses is independent of the cerebellum. The duration and amplitude of the long latency response of the antagonist, however, seems to be controlled by the cerebellum.

Afferent Pathways↗