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Biomedical subjects

J G Blackburn

Publications and source records attributed to J G Blackburn.

6 recordsLinked to original sources

The effects of low spinal injury on somatosensory evoked potentials from forelimb stimulation.

Spinal cord transection below C6 in anesthetized cats results in an alteration in the configuration of the SEP following direct or percutaneous stimulation of the median or radial nerves. The most significant alterations were in components occurring at latencies from 40 to 60 msec. The results of these experiments support the general conclusion that the spinal cord and supraspinal structures act as a functional unit and that the SEP is not solely determined by input over segmental pathways In addition, the alteration in the SEP produced by median nerve stimulation following spinal cord injury below C6 may serve clinically as a monitor of events at the site of injury in cases where an SEP from lower limb stimulation is no longer obtainable.

Animals

The effects of interaction between large and small diameter fiber systems on the somatosensory evoked potential.

The effect of interaction between large and small diameter fiber systems on the somatosensory evoked potential (SEP) was studied in anesthetized cats. Activation of large diameter fibers of the peroneal or radial nerves eliminates the late components of the SEP produced by stimulation of all fibers in the contralateral median or radial nerves. The inhibitory effects of a selective conditioning stimulus to the large diameter fibers of the peroneal nerve on the radial nerve evoked SEP was eliminated by bilateral transection of the dorsal column and spino-cervical tracts. However, interaction could still be obtained following transection when both large and small diameter fibers in the peroneal nerve were stimulated. The results of this study support the hypothesis that a correlation exists between activity in different fiber groups in afferent nerves, their conduction pathways through the cord, and the components of the cortical evoked potential.

Afferent Pathways