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Biomedical subjects

K Horch

Publications and source records attributed to K Horch.

26 records · Page 2Linked to original sources
PubMed1982

The influence of mechanoreceptor structures on regenerating sensory axons after cutaneous nerve transection in the cat.

After nerve transection, cutaneous type I mechanoreceptors (Haarscheiben or tactile domes) preferentially reappear at old loci, although some do appear at new locations. The mechanism by which this topological specificity is maintained was studied by transecting the femoral cutaneous nerve in cats in which about half of the Haarscheiben were removed by cauterization. Thirteen months after nerve transection, domes were found on uncauterized sites at a rate significantly greater than that expected by chance alone, but on cauterized old dome sites at a rate expected by chance alone. It is concluded the reappearance of type I receptors at old receptor sites following nerve transection is primarily due to intrinsic properties of the receptor sites, rather than to guidance of regenerating axonal sprouts to these sites by the endoneurial matrix of the distal stump of the lesioned nerve.

Animals↗
PubMed1979

Guidance of regrowing sensory axons after cutaneous nerve lesions in the cat.

1. Individual type I sensory neurons in cutaneous nerves typically innervate two to four type I cutaneous mechanoreceptors (Haarscheiben). The extent to which these neurons replicate the original innervation patterns of the type I receptors after peripheral nerve regeneration and the means by which these neurons are guided back to their old receptor sites during regeneration were studied in cats using neurophysiological techniques. 2. By recording activity of type I neurons in small cutaneous nerves and isolated dorsal rootlets, it was possible to map the distribution of these neurons in the skin. Maps made before nerve lesion were compared to maps made after recovery from nerve crush and transection. 3. Fibers regenerating after nerve crush return to their old receptor sites, probably by following their old Schwann tubes in the distal stump of the nerve, and replicate the original receptor innervation pattern. Essentially all the type I fibers successfully regenerate in this case. 4. In contrast, after nerve transection the regenerating fibers do not restore the original innervation pattern, although they do preferentially return to other old type I receptor sites. About 60% of the type I fibers reinnervate the skin after transection. 5. These observations provide a basis for the difference in functional recovery seen after crush and transection lesions of peripheral nerves.

Animals↗
PubMedDate not supplied

Reduced fatigue in electrically stimulated muscle using dual channel intrafascicular electrodes with interleaved stimulation.

Pairs of intrafascicular electrodes were implanted within single fascicles of the nerve innervating the gastrocnemius muscle in cats. Measurements were made of fatigue induced in the muscle by single and dual channel tetanic stimulation. The level and rate of fatigue induced by concurrent dual channel stimulation (pulses presented simultaneously to the two electrodes) did not differ significantly from that induced by single channel stimulation. However, a significant reduction in the level and rate of muscle fatigue was found with interleaved dual channel stimulation. The extent of reduction in fatigue was found to be inversely related to the amount of overlap in the axonal populations activated by each of the two electrodes.

Animals↗
PubMedDate not supplied

A study of sensory recovery following carpal tunnel release.

The purpose of this study was to define the testing parameters that are most sensitive to sensory loss in carpal tunnel syndrome and then to track recovery of these sensations postoperatively. Two dozen patients underwent standard nerve decompression and were subsequently re-evaluated at six weeks, three months, and six months. The test battery included provocative maneuvers, light-touch threshold determined by manually applied monofilaments and skin indentation with the Automated Tactile Tester (ATT), manual two-point discrimination, manual high-frequency vibration and ATT low-frequency vibration, and ATT warmth detection. The most sensitive indicators of sensory abnormality were the ATT low-frequency vibration and skin indentation tests. Responses to all but these two tests returned to normal within two months postoperatively. The ATT indentation and vibration tests showed continual improvement over the study period, returning to nearly normal values by six months. Recommendations concerning the use of automated methods for testing sensory function are made in light of these findings.

Adult↗