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Biomedical subjects

C D Barnes

Publications and source records attributed to C D Barnes.

At least 109 records · Page 6Linked to original sources
PubMed1975

A critical reticular site involved in the spino-bulbo-spinal reflex system.

1. In precollicular decerebrate cats, the nucleus reticularis gigantocellularis in the medullar was identified to be critically involved in the spino-bulbo-spinal (SBS) reflex system. 2. Electrolytic lesion place in this nucleus eliminated the SBS reflex and its associated effects in the spinal cord. 3. Ascending volleys from the spinal cord were found to excite neurons within this nucleus, whereupon further direct stimulation was able to enhance the inhibitory effects of the SBS reflex on spinal motoneurons. These interactions were also facilitated by physostigmine and suppressed by atropine, indicating the cholinoceptive nature of these neurons, another criterion which qualified them as being associated with the SBS reflex. 4. The functional roles of SBS reflex and nucleus reticularis gigantocellularis in somatic and visceral activities were discussed.

Animals↗
PubMed1975

Bilateral effects of vestibular nerve stimulation on activity in the lumbar spinal cord.

These experiments were designed to study the effects of vestibular nerve stimulation on the activity of hindlimb motoneuron pools. Two techniques were used to stimulate the vestibular nerves of precollicularly decerebrated cats. In one set of experiments the individual semicircular canals were stimulated via bipolar electrodes placed near the canal nerves. In the second series of experiments the whole vestibular nerve was stimulated with an electrode placed on the intradural nerve. Activity in the hindlimb motoneuron pools was ascertained by evoking monosynaptic reflexes in the various hindlimb nerves. Stimulation of the individual semicircular canals produced response patterns that varied with both the vestibular branch being stimulated and the hindlimb nerve being conditioned. Intradural stimulation of the vestibular nerve, on the other hand, evoked similar response patterns in the antagonist ankle flexor and extensor nerves. The most common pattern consisted of facilitation followed by a period of inhibition. Lesions of descending fiber tracts produced results which suggest the presence of a diffuse pathway, involving the recitular formation, which mediates the observed responses. It is suggested that the biphasic response pattern is analogous to the startle response and the function of the responses is discussed in that context.

Animals↗
PubMed1975

Spinal and spino-bulbo-spinal reflexes in rats with experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) often produces complete hindlimb paralysis in rats. Stimulating the dorsal root at L5 was found to produce hindleg twitches in EAE rats with complete hindlimb paralysis. In addition, it was possible to record a monosynaptic response from the ventral root at L5 after stimulating the ipsilateral dorsal root (L5) in these rats. It was also possible to elicit a reflex at L5 which was shown to involve the central nervous system above the spinal cord level. These experiments demonstrated that the motoneurons and the muscles of the hindlimbs and the spinal cord segment innervating the hindlimbs remain functional in EAE paralyzed rats. This suggests that the paralysis may be caused by dysfunction of descending pathways of supraspinal origin.

Animals↗