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Biomedical subjects

J Myklebust

Publications and source records attributed to J Myklebust.

7 recordsLinked to original sources
PubMed1978

Evoked potential measurement and analysis on a small laboratory computer.

A program is described for the collection and subsequent analysis of somatosensory evoked potentials using a LINC-8 computer. The program allows simple evoked-potentials analysis in centers where a small laboratory computer may be available but sophisticated instrumentation such as a computer of average transients is not available. This program provides an efficient method of easily obtaining information concerning the conduction pathways of the nervous system as well as the cerebral function; the program can be implemented on small laboratory computers which most hospitals currently own, without the associated cost or complexity of additional hardware in the laboratory. Combining utilization of a small laboratory computer with an easily programmable method provides an approach for evoked potential analysis which is well within the financial and technical scope of most neurophysiology laboratories.

Computers↗
PubMed1978

Early somatosensory evoked potentials.

The early somatosensory evoked potential secondary to median nerve stimulation in the human had an onset latency of 9--12 msec when recorded from scalp electrodes at vertex-to-mastoid, vertex-to-inion or at the base of the skull. Similar latencies were observed from responses recorded over the cervical dorsal columns during neurologic surgery. A latency difference of 1.5 msec was observed between the early response and the responses recorded from the junction of medial lemniscus and nucleus ventralis posterior lateralis of the thalamus during human stereotaxic surgery. Cervical cord transections and transection at the midpontine levels of the monkey showed that the evoked potential was due to generators between these levels. Depth recording of the monkey indicate that the early evoked potential originates in the region of dorsal column nuclei, while the later components are secondary to generators in cerebral cortex.

Animals↗
PubMed1978

Spinal evoked potentials in the primate: neural substrate.

Summated responses evoked by peripheral nerve stimulation were recorded from electrodes located in the epidural and subdural spaces anterior and posterior to the monkey spinal cord. Segmental microsurgical resection of the dorsal columns both at the thoracic and cervical levels resulted in total obliteration of the response recorded rostral to these lesions. Isolated segmental dorsal column preservation did not significantly alter response latency or wave form recorded at the rostral electrodes. Bilateral cervical dorsolateral column resection also resulted in no discernible alterations of these responses. These data indicate that spinal evoked potentials recorded from levels rostral to their root entry zones arise almost exclusively from the dorsal columns.

Animals↗
PubMedDate not supplied

Evaluation of electrode configurations in cerebellar implants.

Capacitively coupled currents of 100 Hz, 0.25 msec duration, were applied to multielectrode arrays implanted upon the superior and posterior surfaces of the chimpanzee cerebellum. The current required for 90% reduction in the amplitude of the evoked potential was inversely proportional to the number of electrodes upon the cerebellar surface. A study of various waveforms showed that z Hz, 0.25 msec pulse duration is near optimal for reduction of amplitude of the somatosensory evoked potential. The current densities per electrode were 5--11 mA/cm2 with a charge per pulse of 0.04--0.08 muC in humans with 15--20 electrodes on each superior surface and 10 electrodes on each posterior cerebellar surface.

Animals↗