Effect of D-tubocurarine immobilization on the resting electroencephalogram in the rat

The EEG curve and the power spectral density curve recorded from the septum, medial hypothalamus, dorsal hippocampus and frontal cortex of adult male rats kept under free activity conditions were compared with analogous curves from the same animals immobilized by D-tubocurarine and subjected to artificial ventilation. Immobilization caused an increase in the proportion of slow activities (up to 2 c/sec) in the hypothalamus, the septum and the hippocampus and the appearance of a second peak in the theta band in the hypothalamus and hippocampus. A simultaneous decrease in fast frequencies (6-15 c/sec) was observed; all these changes took place in subcortical regions only. The differences in EEG patterns are probably brought about by the effect of immobilization which is suggested to induce appreciable alterations in the stimulus field of the animal.