Electrical activity of the posterior thalamic nucleus and the hippocampus during wakefulness and desynchronized sleep in the rat: a spectral analysis.

The electrical activity of the posterior thalamic nuclear complex was studied in rats and related to the simultaneous hippocampal electro-oscillogram. Electrocorticographic tracings and spectral analysis showed that during attentive wakefulness the electro-oscillogram peaked at 8 Hz and in desynchronized sleep it oscillated at regular frequencies between 8 and 9 Hz. In quiet wakefulness, frequency was lower (around 6 Hz) and during synchronized sleep rhythmicity disappeared. The electrophysiological patterns during wakefulness and desynchronized sleep are proposed to be linked to the retrieval and combination of information for the generation of attention and dream content.

Rostrum movements in desynchronized sleep as a prevalent manifestation of dreaming activity in Wistar rats.

Considering that eye movements express visual dreams in humans and are prominent during desynchronized sleep in cats, monkeys and birds, rostrum movements were investigated in a macrosmatic species, the rat, to assess the hypothesis that, expressing olfactory and tactile (involving the vibrissae) dreams, they would prevail over eye movements. Desynchronized sleep episodes lasted 148.8 +/- 12.4 s, rostrum movements lasted 80.7 +/- 6.9 s and eye movements occurred during 40.4 +/- 3.9 s, all in accordance with the original hypothesis.