Biomedical subjects

J Myklebust

Publications and source records attributed to J Myklebust.

20 records · Page 2Linked to original sources

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↗

PubMedDate not supplied

Continuous quantitative local cerebral blood flow measurement. Calibration of thermal conductivity measurements by the hydrogen clearance method.

The capability of a miniaturized probe to measure local cerebral blood flow in a continuous and quantitative manner is described. The incorporation of thermal conductivity measurements using the isothermal principle with the hydrogen clearance method allows calibration of the thermal conductivity component in absolute terms. Evaluation of this system in 14 cats showed a linear relationship between both measurement methods. The major limitation of this combination probe system is the need for routine intermittent recalibration in order that changes of tissues thermal conductivity induced by physiologic alterations during the experimental procedure may be recognized and resolved.

Animals↗