The states of sleep
Michel Jouvet
Scientific American (1967)
TABLE OF CONTENTS

Introduction

Brain Activities in Sleep

The Two Sleep States

The Suppression of Wakefulness

Sleep Centers

Paradoxical Sleep

The Evolution of Sleep

The Chemistry of Sleep

FIGURES

PRINT
Printable version

Figure 10

PARADOXICAL SLEEP

among three vertebrate classes of increasing evolutionary complexity is shown as a percentage of each animal's time spent in light sleep. None is known in the case of the reptile, a tortoise; in the case of the hen it is only two-tenths of 1 percent of the total. In the case of each of the four mammal species shown, the newborn spend at least twice as much time in paradoxical sleep (color) as do their adult counterparts (black).