Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “REFLEX, POSTURAL”

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 1,045 records · Page 58Linked to original sources
PubMed1981

Locomotion elicited by pinna stimulation in the acute precollicular-postmammillary decerebrate cat.

In the acute precollicular-postmammillary decerebrate cat, pinna stimulation was found to elicit four-legged locomotion on the treadmill. The adequate stimuli for eliciting locomotion were of the nature of deep pressure with the fingertips. The receptive field of the pinna were distributed along the edge of the scapha. When the existing postural tonus after decerebration were highly exaggerated or depressed, the same stimulation failed to elicit locomotion.

Animals↗
PubMed1987

The effect of chronic ethanol consumption on the fine structure of the CA1 stratum oriens in short-sleep and long-sleep mice: short-term and long-term exposure.

The effect of chronic ethanol administration on the fine structure of the hippocampal CA1 stratum oriens was examined in two lines of mice selectively bred for their differential sensitivity to acute ethanol exposure (long-sleep, LS and short-sleep, SS mice). Two experiments were performed. In the first experiment, mice received a liquid diet for 3 weeks with the final amount of ethanol being 35% ethanol-derived calories. In the second experiment, mice received 23.5% ethanol-derived calories for 3 months. Quantitative electron microscopy of the dendritic spines and synaptic appositions in the stratum oriens of CA1 revealed an interaction between diet and line of mice, but only in the 3-month exposure condition. This difference was due to a significant decrease in the density of spines and synaptic appositions in the LS mice receiving ethanol. Additionally, baseline differences between lines indicate that the lines are differing in the density of spine synapses in the absence of ethanol treatment. The possible interaction between acute sensitivity to ethanol and differences in fine structure are examined.

Animals↗
PubMed1991

GABA mediated inhibition of abdominal postural flexion in lobster.

Swimmeret mechanostimulation initiates an abdominal extension program which includes flexion inhibition. Agonists and antagonists were used to examine the GABAergic nature of inhibitory responses recorded intracellularly from a flexion producing interneuron (FPI 303) and flexor motor neuron (f3) pair, and extracellularly from the other flexor efferents. The GABA antagonist picrotoxin (PTX) enhanced spontaneous flexion. As PTX levels increased, the swimmeret evoked response shifted from inhibition of flexion (less than 10 microM), to inhibition followed by excitation (10-30 microM), to flexion excitation (greater than or equal to 50 microM). The irreversibility of PTX effects, and the absence of bicuculline or baclofen induced changes in flexion activity, suggests that the receptors differ from mammalian GABA receptors. Both GABA and its agonist muscimol suppressed flexion activity and reduced intracellular potential amplitudes. Proof that PTX acts by binding the GABA receptor was obtained by observing that the addition of GABA or muscimol to preparations pretreated with PTX did not affect either spontaneous or swimmeret evoked activities, or intracellular potential amplitudes. These results imply involvement of GABAergic interneurons in the abdominal motor programs which inhibit flexion.

Abdomen↗
PubMed1991

Descending inhibitory pathway responsible for simultaneous suppression of postural tone and respiration in decerebrate cats.

The present study was performed in order to elucidate whether the suppressive effects on postural tone and respiration evoked by stimulation of the dorsal tegmental field (DTF) of the pons are relayed through the neurons in the ponto-medullary reticular formation. First, the DTF was functionally identified, and then a microelectrode was inserted into the caudal pontine and medullary reticular formation to investigate the distribution of the neurons monosynaptically activated by stimulation of the DTF. The monosynaptically activated neurons were distributed within the nucleus reticularis gigantocellularis (NRGc) in the caudal pons and medulla. The spinal cord (L1) was stimulated to study whether such monosynaptically activated neurons project to the spinal cord. Almost all the neurons monosynaptically activated by DTF stimulation were antidromically activated by spinal stimulation. This result indicates that the neurons in the NRGc activated monosynaptically by DTF stimulation send axons to the spinal cord. Tonic micro-stimulation was then delivered to the site in the NRGc, from which the monosynaptically driven units were recorded by DTF stimulation. The stimulation resulted in the parallel suppression of postural tone and respiration, similar to the suppressive effects elicited by DTF stimulation. The present study suggests the possible existence of a descending inhibitory pathway through the reticulospinal neurons in the NRGc responsible for parallel suppression of postural tone and respiration.

Animals↗
PubMed1988

Reproducibility and adaptation of the EMG responses of the lower leg following perturbations of upright stance.

The electromyographic (EMG) response of gastrocnemius, soleus and anterior tibialis muscles to a backwardly directed perturbation of stance was recorded in 12 normal subjects using surface electrodes and studied with regard to its reproducibility (test-retest reliability coefficients, variability coefficients) and to adaptational effects. (1) Reproducibility was shown to be uniformly high and can be interpreted as an index for the high intraindividual constancy of the results. (2) Adaptational effects have been found and should be circumvented, either by pre-adapting the subjects to the motor task, or by restriction of the period of measurement. (3) Variation of the position of the electrodes produced only small effects. The impedance of the surface electrodes was not critical if kept below 5 k omega. EMG investigations with surface electrodes during stance and perturbations of stance provide highly reliable results with respect to intraindividual changes but interindividual variability of the results clearly marks the limits of this method. The interindividual variability observed with surface electrodes is of the same order as that reported in the literature for inserted needle recording.

Adaptation, Physiological↗
PubMed1991

Cardiovascular responses to tilting in healthy and diabetic subjects.

Cardiovascular responses to tilting from supine to upright and back to supine were investigated by measuring heart rate (HR) and blood pressure (BP) continuously by non-invasive methods. Subjects were 20 healthy controls, 17 diabetic patients (DN) with normal test results for parasympathetic cardiac function and 21 diabetics (DA) with abnormal results. In control subjects, tilting up and tilting back maneuvers induced opposite changes in HR, systolic (SBP) and diastolic BP (DBP). The most obvious responses appeared during the first 30 sec after either maneuver. The best measurements to detect sympathetic vasoconstrictor abnormalities during tilting up were derived from the recovery curve that followed the immediate fall in SBP, abnormal in 6 DN and 14 DA patients, and from the increase in DBP after the maneuver, abnormal in 7 and 16, respectively. Tilting back induced comparatively larger cardiovascular responses. The SBP remained stable after 10 sec in the controls, but increased above normal limits in 7 DN and 20 DA patients. The DBP fell during the first 10 sec in controls, but not in 4 DN and 17 DA patients. Continuous monitoring of BP during tilting is a more sensitive test of autonomic function than classical BP measurements made at a few selected intervals. The results challenge the view that parasympathetic dysfunction precedes and occurs more frequently than sympathetic dysfunction.

Adult↗
PubMed1992

Postural inflexibility in parkinsonian subjects.

In order to identify the types of postural deficits seen in parkinsonian patients with postural instability, we compared the performance of parkinsonian subjects with young and old control subjects in 3 aspects of postural control: (1) the use of sensory information for postural orientation, (2) the coordination of postural movement patterns in response to surface displacements, and (3) the flexible modification of postural response patterns to changes in support conditions. Parkinsonian subjects had very small sway, even under altered sensory conditions. Postural response latencies to displacements were also normal. Postural instability was associated with abnormal patterns of postural responses including excessive antagonist activity and inflexibility in adapting to changing support conditions. Some parkinsonian subjects appeared to have difficulty sequencing motor programs for postural correction. The parkinsonian subjects appeared stiffer since the rate-of-change of sway in response to displacements was reduced. Levodopa improved postural coordination but not the flexible adaptation to changing support conditions.

Adult↗