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At least 217 records · Page 12Linked to original sources
PubMed1990

Hemicerebellectomy and motor behaviour in rats. I. Development of motor function after neonatal lesion.

This study was undertaken to determine the effect of a neonatal hemicerebellectomy (HCb) on the motor development of rats and to determine whether various aspects of motor behaviour were affected to a similar degree. Postnatal development of postural reflexes, locomotion and dynamic postural adjustments was examined during the first four months of life in normal and in neonatal HCbed rats. The results indicate that classes of motor responses are controlled by cerebellar networks to clearly different extents. Emergence of quadruped stance, placing reactions and swimming development were unaffected by neonatal cerebellar lesion. Righting reflexes, cliff avoidance and geotaxic reactions, pivoting and crawling all showed a delayed development although the subsequent recovery was almost complete. The complex postural adjustments required in crossing a narrow path or in suspending on a wire remained permanently impaired. Finally, some behaviours developed normally and only subsequently became defective. This "growing into a deficit" was displayed by the progressively reduced hindlimb grasping and the development of a vestibular drop response with a directional bias. An impressive finding was the shifting of postural asymmetries from the lesion side to the contralateral one occurring around the third postnatal week. These data providing a description of the effect of HCb on motor development are interpreted as indicating a progressive involvement of the archi- and neo-cerebellar structures in the motor function of the rat.

Animals↗
PubMed1997

A population perspective on diagnostic criteria for Parkinson's disease.

For Parkinson's disease (PD), little is known about how the choice of diagnostic criteria affects research results. Using data on PD from three community studies (from Argentina, the Netherlands, Italy), we compared the impact on prevalence of several sets of diagnostic criteria. Each set was based on cardinal signs--resting tremor, bradykinesia, rigidity, impaired postural reflexes--and required that other parkinsonism be excluded. Some sets had additional requirements related to duration of symptoms, asymmetry of signs, or response to medication. In terms of prevalence, much lower estimates were associated with the requirements of asymmetry of signs and response to medication. The assessment of these clinical features may not be practical in community studies. Impaired postural reflexes, as a cardinal sign, seemed superfluous. For community studies of PD, we recommend the following diagnostic criteria: at least two of resting tremor, bradykinesia, or rigidity, in the absence of other apparent causes of parkinsonism.

Age Distribution↗
PubMed1990

A comparison of ketamine/xylazine and ketamine/xylazine/acepromazine anesthesia in the rabbit.

Parenteral anesthetic combinations such as ketamine and xylazine have become the agents of choice for anesthesia in the rabbit, because they are effective, easily administered and inexpensive. A number of recent reports have recommended including acepromazine in this combination, but a critical evaluation of this combination in the rabbit has not been reported. Five adult New Zealand white rabbits were anesthetized intramuscularly with ketamine (35 mg/kg) and xylazine (5 mg/kg) with or without acepromazine (0.75 mg/kg). The study was conducted in a double blind fashion, where each rabbit was administered both combinations at a minimum of 7 day intervals. Physiologic parameters were evaluated including heart rate, respiratory rate, central arterial blood pressure, pedal, palpebral and postural reflex activity. The duration of general anesthesia, estimated by the time elapsed between the loss and return of the palpebral reflex, was greater (means = 99 +/- 20 minutes) when acepromazine was employed in the combination compared to (means = 77 +/- 5 minutes) when ketamine/xylazine were used alone. Mean central arterial blood pressure reached a lower level when acepromazine was utilized (means = 46 +/- 8 mm/Hg) than when it was not (means = 57 +/- 12 mm/Hg.). The addition of acepromazine in a ketamine/xylazine combination resulted in a 28% longer period of anesthesia, a 19% lower mean central arterial blood pressure and a 32% longer recovery of postural reflexes. The ketamine/xylazine/acepromazine combination is a useful regimen for normovolemic animals when anesthetic duration greater than that produced by ketamine/xylazine alone is required.

Acepromazine↗
PubMed2001

Gait festination in Parkinson's disease.

Background: Festinating gait (FSG) was first associated with parkinsonism by Sir James Parkinson, in his original essay on "The Shaking Palsy". Its frequency and relation to other parkinsonian features have never been assessed.Objective: To study the relationships between gait festination and other parkinsonian clinical features among patients with Parkinson's disease (PD).Method: During an open lecture to patients with PD who are followed at the Movement Disorders Unit (MDU) of Tel-Aviv Sourasky Medical Center one of us explained verbally and imitated festinating gait on stage. All attending patients with the help of their care-givers or family members, were asked to answer two written questions regarding their own experience with FSG as well as the degree of disability it causes. Clinical information about each patient was taken from his/her chart at the MDU and missing data was completed during the next office visit or from the family physician. Statistical analysis was performed using t-tests for comparison between groups, Chochran-Armitage test for trends and logistic regression to assess the contribution of age of onset, disease duration and disease severity to the development of FSG.Results: Eighty-one PD patients (58 males, mean age 67.5+/-10.7years) answered the FSG questionnaire. Our study population's mean disease duration was 8.5+/-6.4years, mean Hoehn and Yahr (H&Y) clinical stage of 2.6+/-0.8 and mean levodopa dose of 608+/-375mg/day (15 patients were not on levodopa). Twenty-six patients (32.1%) experienced FSG during the previous month and 56% of them reported that FSG was a significant and disabling symptom. FSG was strongly associated with higher stage of H&Y (p<0.001) with a significant trend as the disease progresses (p=0.001) but not with total score in the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS). Longer disease duration was the only clinical factor, which was found to be associated with FSG in the multivariate model. Thirty seven percent (37%) of the patients with FSG reported frequent falls with association between occasional or frequent falls, as reported on the activity of daily living (ADL) part of the UPDRS, and the presence of FSG (p<0.08). There was no association between significant postural reflex abnormalities as rated on the objective part of the UPDRS and the presence of FSG. There was a significant association between the presence of freezing of gait (FOG) as reported in the ADL part of the UPDRS and the presence of FSG (p<0.001) as well as a significant trend towards more frequent FSG in patients with more severe FOG (p<0.001).Conclusion: FSG was clearly associated with longer duration of PD symptoms but not with disease severity as reflected in the motor part of the UPDRS. The relationships between FSG and postural reflexes abnormalities is unclear but it is frequently associated with falls and freezing of gait.

Journal Article↗
PubMed1995

Nonocclusive common carotid artery thrombosis in the rat results in reversible sensorimotor and cognitive behavioral deficits.

BACKGROUND AND PURPOSE: Microemboli released during transient ischemic attack, stroke, and cardiac surgery are thought to cause a variety of functional deficits in humans. The purpose of this study was to characterize the type and extent of neurobehavioral deficits present after photochemically induced common carotid artery thrombosis (CCAT), a thromboembolic model of stroke in the rat that results in a platelet emboli shower. METHODS: Thirty-two male Wistar rats were assigned to four groups. Groups 1 (n = 8) and 3 (n = 8) were long-term (6-week survival) and short-term (2-week survival) experimental groups subjected to right CCAT with the use of the photochemical technique. Groups 2 (n = 8) and 4 (n = 8) served as sham-operated controls for each experimental group. A battery of behavioral tests was applied daily beginning 24 hours after thrombosis; this consisted of elicited forelimb placing, postural reflex, beam balance, beam walking, and open field activity. Cognitive testing with a water maze task was performed on post-CCAT days 30 to 33 for groups 1 and 2 and on post-CCAT day 2 for groups 3 and 4. Ten-micrometer coronal brain sections were stained with hematoxylin and eosin, and infarct location and frequency were determined. RESULTS: Significant sensorimotor deficits were observed, which recovered within 2 weeks after CCAT. The data that follow are derived by combining the two experimental groups and comparing these with the two sham groups. The following tests showed significant effects after CCAT: contralateral elicited forelimb placing, ipsilateral elicited forelimb placing, beam balance, and beam walking score. Cognitive dysfunction was seen acutely (group 3 animals) at 2 days after CCAT; Morris water maze length and latency to target were significantly greater in the experimental group. No deficits were seen in postural reflex, open field activity, or delayed cognitive testing. Histopathological assessment revealed small infarcts in 11 of 16 thrombosed rats. However, a strong relationship between neurobehavioral deficits and infarct location was not consistently demonstrated. CONCLUSIONS: CCAT produces consistent sensorimotor and cognitive behavioral deficits that recover within 2 weeks of injury. Behavioral outcome was not necessarily associated with overt histopathological damage, suggesting that reversible injury mechanisms, both vascular and neuronal, may be partly responsible for the temporary loss of function. These data strengthen the role of CCAT as a clinically relevant model of thromboembolic stroke.

Animals↗
PubMed1985

Severe head injury in children: early prognosis and outcome.

The outcome is reported in 62 children with severe head injuries following a road traffic accident. All patients were comatose for at least 6 h; all patients were graded using the Glasgow Coma Score (GCS) or the Children Coma Score (CCS). Fifty-four patients were comatose immediately after injury, 8 after a lucid interval. Thirty patients had isolated head injuries and 32 had associated injuries, either long bone fractures or rupture of an abdominal organ. Additional information concerning main brainstem reflexes, posture and respiration was included in the study. The overall mortality was 32%. The goal of the study was to identify those clinical features available soon after injury which are important indicators of treatment and outcome.

Accidents, Traffic↗
PubMed2002

Influence of imaginary target on "dumping" of vestibulo-ocular reflexes and postural control.

Two studies explored 1) the effect of instruction set upon the well known "dumping" of the vestibulo-ocular (VOR) post-rotatory nystagmus long time constant (TC) and 2) the effect of imaginary earth-fixed targets on postural control. Imaginary targets do not produce dumping and do not improve postural stability, with or without pitch head movements.

NASA Discipline Neuroscience↗
PubMedDate not supplied

Recovery of postural control after an acute unilateral vestibular lesion in humans.

Postural control during stance was investigated using the EQUITEST system in 10 patients during recovery after an acute unilateral vestibular lesion and was compared to the time course of recovery of the static and dynamic vestibulo-ocular imbalance. During the acute phase the patients showed a characteristic pattern with normal upright stance as long as at least one accurate sensory input (visual or somatosensory) was provided and severe postural disturbances when they had to rely primarily on vestibular afferences. Both static vestibulo-ocular and vestibulo-spinal balance recovered very fast, showing basically normal results on postural testing within about 2 weeks after the lesion. Thereafter, no pathological pattern was detectable during postural testing even in patients with persistent complete unilateral vestibular lesions. Reflexive postural responses to unexpected rapid displacements of the support surface seemed not to be influenced by vestibular imbalance even in the acute phase of the lesion.

Acute Disease↗
PubMed1983

Effect of interruption of bulbospinal pathways on lordosis, posture, and locomotion.

The effect of interruption of descending bulbospinal projections arising from (i) the medial medullary reticular formation: nucleus reticularis gigantocellularis (NGC) and nucleus reticularis magnocellularis (NMC), (ii) nucleus raphe magnus, and (iii) nucleus subceruleus on the lordosis reflex, posture, and locomotion was examined. After interruption of descending NGC-NMC fibers, time-dependent deficits in lordosis were observed during the first two postoperative weeks with subsequent reflex recovery. A syndrome of postural and locomotor deficits occurred after NGC-NMC lesions. Postoperatively, postural reflexes were dominated by increased extensor tone which resulted in limb hyperextension. Specific time-dependent deficits in the control of extensor and flexor muscle groups involved in locomotion resulted in a motor syndrome that is detailed. After interruption of NMC fibers alone, no postural or locomotor deficits occurred and effects on lordosis were limited to the first few postoperative days. The NMC data suggested that the majority of the functional deficits seen after NGC plus NMC lesions were due to destruction of the NGC descending projections. Interruption of NSC bulbospinal fibers resulted in a significant depletion of spinal cord noradrenaline (NA) but not serotonin (5-HT). Functional deficits, when present, were limited to the first few postoperative days. Although interruption of descending NRM fibers resulted in a significant depletion of spinal cord 5-HT concentrations, greater depletions occurred in the NGC plus NMC group. No functional deficits were observed in the NRM group. These data suggest that interruption of NGC-NMC fibers destroyed the descending output from neurons which integrate the hormonal and sensory information necessary for lordosis.

Animals↗
PubMed1987

Quantitative diagnostic test for perilymph fistulas.

Clinically, the definitive diagnosis of perilymph fistulas can only be made by tympanotomy. Results of various fistula tests based upon the vestibulo-ocular reflex have not correlated well with findings during tympanotomy. A new fistula test has been developed based upon vestibulo-spinal responses. By systematic removal of both visual and support-surface orientation references from the subject--leaving only vestibular control of postural reflexes--patients with perilymph fistulas demonstrated an increased (sometimes phase-locked) postural sway in response to sinusoidal changes in external auditory canal pressures. Results from 100 consecutively operated ears (64 patients)--77 of whom underwent preoperative and postoperative moving-platform fistula tests--indicate that the test sensitivity is 97 percent for this highly selective patient population. Absolute specificity could not be determined because, on patients without clinical indications for surgery, tympanotomy is contraindicated.

Adolescent↗
PubMed1982

Spiking local interneurons mediate local reflexes.

A local spiking interneuron in the locust is excited by particular sensory stimulation of a hind leg and forms an inhibitory connection with one hind leg motor neuron. Its behavioral effect is to mediate a local postural reflex. This interneuron is one of a population of interneurons with similar morphology and physiology that participate in the same local circuits as the better known nonspiking local interneurons.

Animals↗
PubMed2005

Pathological mechanism of idiopathic scoliosis: experimental scoliosis in pinealectomized rats.

The pathological mechanism of curve progression in idiopathic scoliosis is still obscure. In this study we investigated the pathological mechanism of idiopathic scoliosis in experimentally induced scoliosis in rats. A total 30 rats were divided into three groups: ten bipedal rats with a sham operation, which served as the control; ten quadrupedal rats with pinealectomy; and ten bipedal rats with pinealectomy. Scoliosis developed only in pinealectomized bipedal rats and not in pinealectomized quadrupedal rats. Cervicothoracic lordosis developed in bipedal rats with or without pinealectomy. These deformities of lordoscoliosis in pinealectomized bipedal rats were similar to human idiopathic scoliosis. Lordosis or lordotic tendency was sufficient to cause the spine to rotate to the side. Rotational instability of the spine with rotation of lordotic segment appears to produce a characteristic scoliotic deformity as a secondary phenomenon. Our findings suggest that lordosis may develop in bipedal rats, but pinealectomy is required for the development of lordoscoliosis. Balanced muscle tone controlled by the postural reflex is important to maintain normal posture with a straight spine in the bipedal condition. The disturbance of equilibrium and other postural mechanisms secondary to a deficiency of melatonin after pinealectomy may promote development of lordoscoliosis with vertebral rotation especially in the bipedal posture.

Animals↗
PubMed1977

Direction-specific optokinetic modulation of monosynaptic hind limb reflexes in cats.

The excitability of hindlimb extensor and flexor motoneurons is tonically modulated by animal tilt and a large visual stimulus rotating about the animal's line of sight. This direction-specific modulation is opposite for extensor and flexor motoneurons and opposite for optokinetic and vestibular stimuli, thus combining to a functionally significant pattern of postural reflexes.

Animals↗
PubMed1982

Flexor and extensor postures in sedative drug-induced coma.

Flexor and extensor postural reflexes are most commonly seen in coma after structural brain lesions, but may also occur in metabolic coma. We report 10 patients who exhibited flexor or extensor posturing as an early and transient feature of coma resulting from sedative drug ingestion. In comatose patients with normal pupillary reactivity but no ocular movements, these postural responses suggest sedative drug overdose.

Adult↗