'-.:'' 



II vxiiln « >K ' '1 PHYSIO! "<."> 



Mi koi'in mi .1 nc;v III 



II DAYS 



ik. I.. EEG sleep records in the same 

 , had .11 iiiili -l. hi agea I he firsi io to i g days 

 sliuu little activity characteristic "I sleep 

 beyond the age of i month. Note cln- incipient 

 slow waves and, in the motor and frontal 

 i, , ords in mi the stai i. an ini ipient sleep 

 pindle burst. Records at /'<; and jHd rfayj 

 ari composed "I slow waves and periodii 

 spindle bursts, and differ little from those of a 

 i- in 2-month-old child, 0, occipital; /'. 

 parietal; M, motor; A, frontal. [From l.ind- 

 sley Si Ellingson, unpublished data obtained 

 ,m l in Cradle Society, Evanston, Illinois, 

 1949. 



nouv\ 

 280 DAYS 



M^A^W^^MiAli^V/^ 



and their behavioral correlates Lindsle) (159) de- 

 veloped the concepl ol a continuum (see fig. 11 and 

 table 1 I. Figure 1 1 shows some of the stages of the nor- 

 mal EEG extending from an activated or excited state 

 with low-voltage fast activity .is in arousal or alerted 

 states to deep sleep with large, random slow waves. 

 During .1 relaxed state of wakefulness more or less con- 

 tinuous, amplitude-modulated alpha waves are char- 

 acteristic. In drowsiness alpha waves diminish and 

 low-amplitude slow waves begin to appear. In light 

 in moderate sleep spindle bursts and slow waves are 

 conspicuous and in deep sleep only large and random 

 slovt waves are seen 



[able 1 lists the full range of EEG stages against .1 

 behavioral continuum, and the corresponding states 

 ,.i awareness and behavioral efficiency. Ii should be 



noted that the most aroused or excited State hchavior- 



,ilK is represented by a low-voltage fa 1 EEG picture, 

 .ind is paralleled by pooi attention and behavioral 

 efficiency On the other hand a slight!) less ictivated 

 state, corresponding to alert attentiveness, favors se- 

 lective and shifting attention, and behavioral 

 1 1, iency. The optimal alpha rhythm occurs in a re- 

 laxed state of wakefulness where attention is not 

 fixed Iheie are indications thai awareness 01 con- 

 sciousness shows its broadest sweep or scan and per- 

 haps its lowest threshold in the stage of relaxed wake 

 fulness and optimal alpha rhythm. The threshold is 

 elevated and the held restricted as drowsiness and 



lighl sleep develop. Il is pioh.iliK in ihe Stage ol light 



sleep that consciousness is lost, since in thai stage 

 there 1- lack ol awareness ol things going on externally 

 and la< k ol ability to make perceptual discriminations. 

 r,. yond thai poinl in the due, tion ol deeper sleep 



there is no awareness or ineniorv lor events, except 



tAWIIKH 



RELAXES 

 OXOW S T 



DEE' SLEEP 



in. 11. Normal EEG records characteristic of different 

 stages on the sleep-wakefulness continuum (see table t) ["hi 

 only major omission in the series would be between excited and 

 relaxed, where there should be a low-voltage record resembling 

 excited, but with less marked activation, labeled attentive. [From 

 Jaspei 11.', 



possibly for dreams which usually are accompanied 

 l>\ a momentary elevation of the pattern of the I'.I'Xi 

 toward wakefulness and alpha rhythms. There are 

 still manv questions about dreams, and recent work 



on this topic will be taken up subsequently. 



With respect to consciousness and attention, shifting 

 upward on the continuum from relaxed wakefulness 



with alpha waves lo alert attentiv eness and an acti- 

 vated or desv nchroni/ed I.I.Ci with low -amplitude 



fast waves, attention m. iv he heightened or focused 



