Aim:To observe the effects of some anti-motion sickness drugs on EEG power spectra during vestibular
stimulation in rabbits.
Methods:The vestibular stimulation used was a continued 45 min sinusoidal rotation with a peak angular speed of 60°/s and a cycle of 4 s. Results:(1)This rotatory stimulation increased be and G(δ+θ)/(α+β)in saline-treated control animals.(2) After the adminis-tration of
scopolamine, G(δ+θ)/(α+β),Gδ and Gδ/(α+β)all increased but Gδ and Gθ decreased dur-ing the rotatory stimulation.(3) In
anisodamine treated animals, Gθ increased and Gα decreased only in the early period of the rotatory stimulation,while Gδ/(α+β)and G(δ+θ)/(α+β)did not change signif-icantly,(4) After the administration of methylphenidate, Gδ decreased and Gβ increased and,as a re-sult,Gδ/(α+β)and G(δ+θ)/(α+β)decreased significantly. Conclusion: These results suggest that si-nusoidal rotatory stimulation may produce inhibition of cerebral cortex as we have reported previously,which is much consistent with the inhibitory symptoms of central nervous system in motion sickness.Anisodamine and methylphenidate could offset or even reverse this inhibition process. Scopolamine will cause further inhibition of cerebral cortex and thus may be disadvantageous for motion sickness treat-ment.Whereas,methylphenidate may inhibit motion sickness through elevation of arousal level. Anti-motion sickness effects of scopolamine and anisodamine may be related to its effects on some subcortical centers as some other investigators have suggested.Comparing the central and peripheral effects of anisodamine and scopolamine,it is suggested that anisodamine may be more advantageous for anti-mo-tion sickness use than scopolamine.