The responses of single alpha motoneurons to various "natural' stimuli were recorded from dissected ventral root filaments in lightly anesthetized control and recently decerebellate cats. The identity of the motoneurons was established by recording the unitary responses to orthodromic stimulation of nerves innervating the triceps surae muscles in the hindlimb. We recorded only the activity of units which responded to electrical stimulation of the medial or lateral gastrocnemius nerves, though some units responded to stimulation of both these nerves, and some also responded to stimulation of the posterior tibial nerve. The distributions of unit latencies and amplitudes did not differ between the two groups of animals. Baseline firing rates were also similar. However, unit firing rates in response to neck extension, ipsilateral hindfoot dorsi- or ventral-flexion were significantly higher in decerebellate than in control cats. The discharge rates in response to other stimuli, including neck flexion, pinna stimulation, and noxious stimulation in the hindlimb, were not significantly different between the two groups. Since the alpha motoneurons showed an increase in responsiveness only to some stimuli, specific mechanisms probably explain this release. The most important mechanism seems to be a loss of inhibition normally exerted by the cerebellum on vestibular and joint proprioceptive reflexes. The pathways to the ventral horn cells are thought to involve the vestibulo-spinal and reticulo-spinal tracts.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0006-8993(75)90208-5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Schiff-Sherrington phenomenon in a cat with complete spinal cord transection from traumatic dorsocranial luxation of the second lumbar vertebra.
Vet Med Sci
November 2023
Merewether Veterinary Hospital, Newcastle, New South Wales, Australia.
A young stray entire female domestic shorthair cat was presented with symmetrical forelimb extensor rigidity, neck hyperextension and hindlimb paraplegia, characteristic of Schiff-Sherrington phenomenon (SSP), within 30 min of a motor vehicle accident. Radiographic and post-mortem studies disclosed complete transection of the spinal cord from traumatic dorsocranial luxation of the second lumbar vertebra, displacement of the sacrum from the ilium, seventh lumbar and first caudal vertebrae and multiple pelvic fractures. Other causes of forelimb extensor rigidity and neck hyperextension such as decerebrate and decerebellate rigidity were excluded by a lack of neurological signs consistent with these entities and unremarkable findings on post-mortem examination of the cranial cavity and brain and histological examination of the cerebrum, brainstem and cerebellum.
View Article and Find Full Text PDFFibrocartilaginous embolic encephalopathy of the cerebellum and brainstem in a cat.
Open Vet J
December 2018
Veterinary Medical Teaching Hospital, University of Wisconsin-Madison, 2015 Linden Dr, Madison, WI 53706, USA.
A 12-year old male castrated Siamese cat was evaluated for a one-day history of mild obtundation and decerebellate rigidity. Neurological examination findings were consistent with multifocal disease including lesions within the right cerebellum and right brainstem. Investigations included hematology, biochemistry, urinalysis, and urine culture.
View Article and Find Full Text PDFReticular activating system of a central pattern generator: premovement electrical potentials.
Physiol Rep
October 2013
Institute of Physiology, Benemérita Universidad Autónoma de Puebla 14 Sur 6301, Col. San Manuel, Puebla, Puebla, CP 72570, México ; School of Biology, Benemérita Universidad Autónoma de Puebla 14 Sur 6301, Col. San Manuel, Puebla, Puebla, CP 72570, México.
For the first time, here we characterize a bulbar reticular activating system (RAS) of neurons in decerebrate, deafferented and decerebellated cats producing a premovement electrical potential that we named obex slow potential (OSP). The OSP occurs about 0.8 ± 0.
View Article and Find Full Text PDFRostral cerebellar arterial infarct in two cats.
J Feline Med Surg
June 2007
The Queen Mother Hospital for Animals, The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Herts AL9 7TA, UK.
A 10-year-old female neutered domestic shorthair (DSH) cat and a 6-year-old female neutered Siamese cat were presented following a peracute onset of decerebellate rigidity and a cerebellar vestibular syndrome, respectively. In both cats, physical examination and routine blood tests were unremarkable, as was routine analysis of cerebrospinal fluid obtained from the DSH cat. Based on the magnetic resonance imaging (MRI) features - focal wedge-shaped lesion in the cerebellum characterised by hyperintensity in T2-weighted, T2( *)-gradient echo and fluid attenuated inversion recovery (FLAIR) images - a presumptive diagnosis of cerebellar infarct was made in both cases.
View Article and Find Full Text PDFInhibitory effects from various types of dorsal column and raphe magnus stimulations on nociceptive withdrawal flexion reflexes.
Brain Res
October 1999
Department of Human Morphology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
Most of the clinical and research reports agree about the analgesic effects of dorsal column (DC) stimulation, but there is no unanimity about the neural mechanisms involved in this stimulation. The aim of the present study was to compare the effects of segmental and rostral activation of the DCs and to investigate whether these effects are mediated through a brainstem spinal loop. Decerebrate-decerebellate cats were subjected to selective DC lesions at C(1) and C(3) spinal cervical levels and their reflex reactions to natural or electrical nociceptive stimuli were monitored either as withdrawal flexion reflexes or as motorneuronal discharges.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!