Figure 24 : Relationship between pontine electrical activity during
P.S. and the osmolarity of the blood
Chronic pontile animal with hypothalamic island. (1) P.S. during dehydration.
Monophasic spikes grouped in pseudospindles, accompanied by lateral eye
movements (EM). The pontine electrode is situated in the nucleus reticularis
pontis caudalis. (2) P.S. after rehydration (60 ml liquid). Very regular
theta rhythm of 4.5 c/s associated with spikes and eye movements. This
activity was observed only during the first two phases of P.S. after rehydration.
It was never observed in the waking state. Identical pontine activity
has been observed in 4 animals under the same conditions.