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Biomedical subjects

G Karmos

Publications and source records attributed to G Karmos.

29 records · Page 2Linked to original sources
PubMed1986

Comparison of evoked potential changes during classical and instrumental conditioning in cats.

The waveform changes of cortical evoked potentials to click conditioned stimuli were analyzed by a complex computer program developed for sorting nonhomogeneous series of evoked potentials. The changes of evoked responses manifested themselves mainly in the middlelatency waves, while the first components showed only a slight fluctuation during the whole conditioning. A late negative component of 40-50 ms latency was clearly related to the attentive state of the animal. The evoked potentials with increased negative component appeared in different sequences in 'the two conditioning paradigms and in the different phases of the learning process.

Animals↗
PubMed1982

A new multielectrode for chronic recording of intracortical field potentials in cats.

The analysis of intracortical field potentials in freely moving animals may help to reveal the origin of evoked potential components displaying characteristic changes in behavioral experiments. The authors describe a chronically implantable multielectrode made of 7 teflon insulated platinum wires of 75 microns diameter. The novelty of this multielectrode is that the wires are not glued together but penetrate into the cortex independently. In the final position the cut ends serving as recording surfaces are situated in the cortical tissue below each other at equal distances of 300-400 microns. This arrangement made possible the artifact free recording of the evoked field potentials from the different depths of the auditory cortex for months. Phase reversal, known from the classical studies, could be observed only in the first surface positive component, while the late waves appeared homogeneously throughout the whole depth of the cortex.

Animals↗