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Biomedical subjects

V C Abrahams

Publications and source records attributed to V C Abrahams.

50 records · Page 3Linked to original sources
PubMed1971

Spino-spinal mechanisms in the chloralose anaesthetized cat.

1. In chloralose anaesthetized cats the events in the lumbosacral cord that follow stimulation of a forepaw or neck nerve have been examined.2. Four events take place in the lumbosacral cord after forepaw or neck muscle nerve stimulation. These are: (1) a brief period of generalized enhanced motoneurone excitability, (2) a prolonged and as yet unexplained enhancement of monosynaptic reflexes, (3) a period of presynaptic inhibition in muscle and skin afferent fibres, and (4) a prolonged inhibition of spino-bulbo-spinal reflexes.3. A variable and sometimes selective reduction of one or another descending effects follows the placing of small lesions in the anterior portion of the suprasylvian gyrus.

Action Potentials↗
PubMed1970

Cervico-lumbar reflex interactions involving a proprioceptive receiving area of the cerebral cortex.

1. In the decerebrate cat descending cervico-lumbar reflex interactions from neck muscle nerves are absent, and those from forepaw nerves are reduced or absent.2. Lesions restricted to the anterior pole of the suprasylvian gyrus regularly abolish descending cervico-lumbar reflex interactions from neck muscle nerves. The same lesions may reduce or abolish descending cervico-lumbar reflex interactions from forepaw nerves.3. The ascending cortical looping pathway utilized in descending cervico-lumbar reflex interactions is crossed, and the descending pathway from the cerebral cortex is bilateral.

Animals↗
PubMed1969

Hind leg ataxia of cervical origin and cervico-lumbar spinal interactions with a supratentorial pathway.

1. Unilateral section of the nerves to an extensor muscle of the head, biventer cervicis, leads to an ataxia of the hind legs in cats.2. In chloralose anaesthetized cats, shocks to the central end of the cut biventer cervicis muscle nerves leads to direct discharges over lumbosacral ventral roots, to a facilitation of monosynaptic reflexes in flexor and extensor muscles and to a prolonged inhibition of spino-bulbo-spinal reflexes. Such effects are not unique, but follow stimulation of skin and muscle nerves of the forepaw.3. Supratentorial pathways are involved in descending spinal interactions in the chloralose anaesthetized cat, but are more critical for interactions taking origin in biventer cervicis nerve than in forepaw nerves.4. In non-anaesthetized spinal cats showing interactions from forepaw nerves, no interactions could be found taking origin in biventer cervicis nerves. Descending interactions from forepaw nerves could be reduced or abolished by anaesthetic doses of chloralose.5. The rich pathway from biventer cervicis nerve to the superior colliculus does not appear to be involved in the descending interactions reported here as neither stimulation nor ablation of the superior colliculi has any effect on descending interactions.

Anesthesia, Intravenous↗