[Geomagnetic effects on cortico-caudal mechanisms of auditory stimuli processing in cats].
Impacts of geomagnetic disturbances on parameters of an early complex of evoked potentials (EP, up to 100 ms) in the temporal cortex (TC) and the head of caudate nucleus (HCN) due to the auditory stimulus (click, 85 dB) were evaluated in 12 conscious cats. Mean values of the peak time amplitude, expressiveness of each component and latent period were determined. Indices D, H and Z were used to evaluate the magnetic activity. Experimental animals in group-1 displayed an increase in latency of cortical EP against weakened EP expressiveness in the right hemisphere. In HCN EP expressiveness showed a rise in the left hemisphere. In group-2, the latent period of cortical EP grew in parallel to the amplitude and peak negative component. The latent period of caudal EP diminished whereas expressiveness and amplitude of EP components increased. The data suggest that geomagnetic disturbances suppress the cortical reactivity to exteroceptive stimuli and raise the functional activity of the cerebral inhibitory components, as is the caudate nucleus.
Makarova
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D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D002415:Cats / Q000502:physiology*; D002421:Caudate Nucleus / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D008280:Magnetics; D013702:Temporal Lobe / Q000502:physiology