[Participation of the lateral geniculate body in the mechanisms of brain activation].

In chronic experiments on cats with intact LGB, electrical stimulation of the latter (120-190 microA) caused brain activation with the same threshold as the stimulation of the mesencephalic RF or of the thalamic CM with 50-80 microA. With all but the geniculo-cortical connections of the LGB disrupted, the threshold for brain activation increased to 220-400 microA. After LGB coagulation leaving intact all optical tract connections to the superior colliculi and to the brain stem, the adequate cortical activation was only possible with very strong light flashes (250-1000 l). This suggests that the LGB participates in unspecific brain mechanisms and can induce cortical activation regulated afterwards by the cortex itself.