Recording of bioelectrical activity changes in sheep cerebral cortex

Abstract

The aim of the study was to present a practical application of electroencephalographic techniques. The essential aspects of EEG in sheep and its usefulness in the analysis of changes in the CNS, are demonstrated in the paper. The experiments were conducted on 10 ewes, hybrids of the Polish Merino, selected especially for laboratory purposes. There is no standard pattern in encephalographic methods in animals, that's why the authors made a registration of the induced biopotentials in sheep from the experimentally chosen points of the animals head. It was presented during the experiment that the cerebral cortex is characterized by a high dynamism index, which was proved during the experiments on CNS reactions to the factors such as hunger, sonic emission or control xylazine influence. The cerebral cortex of sheep in a vesting conditions reveals a bioelectric activity of a mean amplitude of 30 μV and a frequency of 25 Hz, which confirms existence of a beta [β] rhythm. An application of a sonic stimulus enables the stimulation of the central nervous system of sheep, which is confirmed by an increased mean amplitude (of 23%) and a frequency (of 21%) of the cerebral cortex activity, and also by the electroencephalogram. Results obtained prove that the region of the mesencephalon is characterised by the shortest time of reaction to the introduced stimulus, and the mean time of response is 0.56 seconds (± 0.005 s). The ways of the most suitable practices as well as the chances for unification of EEG method were discussed.