Figure 25 : Duality of the two states of sleep
Ordinates, for each diagram: percentage of P.S. (in black) with respect
to behavioural sleep.(A)Phylogenetic aspect: hatched: newborn; in black:
adult animal. (1) Tortoise: no P.S.; (2) Hen (0.2%); (3) Lamb (17%); sheep
(6.6%); (4) Young rat (55%); rat (15%); (5) Kitten (80%); cat (30%); (6)
Infant (50%); man (20%). From Klein, 1963. (B) Ontogenetic aspect (in
kittens). Abscissa: Age in days. From Valatx, 1963. (C) After selective
deprivation of P.S. during recuperative sleep. Abscissa: Duration of deprivation
in days. (D) After destruction of the pontine reticular formation (posterior
part of the nucleus reticularis pontis oralis and anterior part of N.R.P.
caudalis. No P.S. (E) Chronic pontile animal. No slow sleep.