Search PubMed⌕ Search

Biomedical subjects

E Eidelberg

Publications and source records attributed to E Eidelberg.

At least 37 records · Page 2Linked to original sources
PubMed1981

Commissural projection to the dentate gyrus of the rat: evidence for feed-forward inhibition.

We studied the response properties of interneurons of the dentate gyrus to stimulation of the commissural and perforant path inputs in urethane-anesthetized rats. Commissural stimulation inhibited the population spike evoked by concurrent stimulation of the perforant path. Stimulation thresholds of the interneurons were significantly lower than thresholds of the projection cells. The latency of 3 interneurons was shorter than the onset of the commissurally evoked field response. The results suggest that commissural fibers directly excite interneurons of the dentate gyrus, and the activity of the projection cells may be inhibited in a feed-forward manner.

Animals↗
PubMed1981

Effects of vestibulospinal lesions upon locomotor function in cats.

We used cats to study the consequences of bilateral ablation of the vestibular complex. The animals were very severely ataxic and incapable of head support for nearly two weeks. They gradually regained the ability to stand and to walk on a treadmill, at first with a marked reduction of the extensor components of stepping. After stabilization of recovery we could not obtain decompensation by dorsal hemisection. We conclude that the key consequence of these lesions is a temporary reduction in facilitatory drive to joint extensor muscle groups. Neither the corticospinal nor the rubrospinal tracts mediate the functional recovery observed.

Animals↗
PubMed1981

Anatomical correlates of return of locomotor function after partial spinal cord lesions in cats.

We trained cats to walk on a moving treadmill belt, then subjected them to partial transverse sections of the thoracic spinal cord. Afterwards, we observed their ability to walk on the treadmill, over a period of several weeks, using gait analysis techniques to describe the resultant deficits. The extent of the lesions was verified histologically, and the identity of the spared descending axons from the brain stem was demonstrated by retrograde labeling with horseradish peroxidase. We found that significant sparing or recovery of hindlimb locomotor function is closely linked to sparing of axons in at least one ventrolateral quadrant of the cord. The essential elements probably belong to vestibulospinal and reticulospinal systems.

Animals↗
PubMed1981

Effects of corticospinal lesions upon treadmill locomotion by cats.

We studied the pattern of stepping in cats, before and after the placement of lesions in the corticospinal system. We found a deficit after the lesions, which was characterized by increased extension of the involved hindlimbs during the stance (E2--E3) phase of the step cycle. This deficit lasted two weeks or less. It may reflect loss of inhibitory influences upon extensor motoneuron pools.

Animals↗
PubMed1981

Locomotor control in macaque monkeys.

We carried out experiments on young adult macaque monkeys (M.fascicularis) in an attempt to establish whether or not primates possess a locomotor control system consisting of spinal pattern generators modulated by brain-stem locomotor regions. We could not induce 'spinal stepping' in our subjects after spinal cord transection. Sparing of pathways contained in the central sector of the white matter of the cord was sufficient for stepping and walking. 'Controlled locomotion' was elicited in thalamic monkeys by electrical stimulation of the posterior subthalamic region or the midbrain tegmentum just ventral to the inferior colliculi. We conclude that there are significant homologies between this primate species and the cat regarding the probable existence of supraspinal locomotor control structures, but it seems that the presumed spinal step generators in monkeys depend more on supraspinal inputs than they do in cats.

Animals↗
PubMed1980

Stepping by chronic spinal cats.

We investigated the consequences of spinal cord transection in adult cat. All became capable of stepping upon a treadmill. Two of six animals stepped in the first postoperative testing session, 1 week after surgery. It took up to 6 weeks for the others to start stepping. None of the cats became capable of hindquarter support within 2 months after surgery. There was permanent loss of fore-hindlimb coordination and increased variability in the duration of each step cycle and its components. Coordination between the hindlimbs was also impaired, as signaled by increased variability in the time between foot contacts with the belt. These changes may be due to the loss of timing signals coming down from supraspinal levels to the segmental step generators or - alternatively - to decreased excitability of segmental motoneurons leading to less precise execution of stepping commands from the hypothetical pattern generators.

Animals↗
PubMed1977

On the possibility that opiate and ethanol actions are mediated by similar mechanisms.

Opiates and alcohol modify neuronal electrical activity in many sites of the nervous system. Both act as depressants or stimulants of cell firing depending upon the type of cell studied. Alcohol seems to act upon some nerves by changing their membrane ionic conductance, while opiates seem to affect synaptic events. However, all of the known neural actions of these substances involve calcium-dependent mechanisms. A hypothesis is proposed to account for these facts.

Animals↗
PubMed1977

An improved electronic pantograph.

A device was developed to permit simultaneous observations of a microscopic field, under any light optic conditions, and permanent recording of the relative X-Y coordinates of the center of the field. A modification is described that allows gray scale values to be assigned to the plots. The system can be readily adapted to digital computer data entry.

Electronics↗
PubMed1977

The pathophysiology of spinal cord injury.

The definitive treatment of severe injuries to the spinal cord is yet to be established, except in the few rare cases in which realignment or decompression results in functionally significant salvage of long tracts coursing through the injured cord segments. The author believes that the best chances for successful therapy lie in a better understanding of the process of spinal cord self-destruction.

Animals↗
PubMed1976

Role of the dorsal funiculi in movement control.

We trained monkeys to perform visuomotor tracking tasks in which the target's position was unpredictable, or in which the target jumped from one side of the screen to the other ('ballistic'). Section of the right dorsal funiculus at C2 resulted in transient deficits in both tasks, with full recovery of function. Subsequent removal of postcentral cortex in the left hemisphere produced a more intense and stable deficit in performance. We conclude that proprioceptive data on limb position and movement must be able to reach motor command structures by pathways paralleling the dorsal column-medial lemniscus system.

Animals↗
PubMed1976

Treatment of experimental spinal cord injury in ferrets.

A variety of treatment modalities upon a compressive model of spinal cord injury in ferrets was tested. Several of the treatments seemed to increase the degree of anatomical and/or functional sparing, but only dexamethasone did so in a statistically significant manner.

Animals↗
PubMed1976

A model of spinal cord injury.

We report here a model of submaximal spinal cord injury, employing direct thoracic cord compression in ferrets. This yields consistent and reproducible long term consequences on local cellular structure and on locomotive function. We show also that both the anatomical and functional losses can be measured objectively using simple techniques, and that useful long-tract mediated locomotion is preserved after severe axonal losses at the site of injury.

Animals↗