1 ,84 



II Willi! M IK OF PHYSIOLOGY 



NEUROPIIYSKH .(ICY III 



fic. 13. EEG record (it an 

 electroshock convulsion similar to 

 the grand mal attack in tig. 1 j. 

 The record was started 8 sec. 

 alter the shock to avoid shock 

 artifact. The record begins with 

 the tonii phase and high-voltagi 

 fast activity; consciousness was 

 lost immediately. The clonic 

 phase follows quickly with first, 

 3-per-sec. waves, then slowing 



to 1 per sec., and subsequently 



to the flat isoelectric period 

 during which the patient was 

 Completely relaxed. The end of 

 the record shows large random 

 slow waves gradually organizing 

 into a sequence of large I-per-sec, 

 waves characteristic of deep 

 sleep. J From Lindsley, unpub- 

 lished observations. I 



*f*rrW**vvWW^^ 



^-^-w, — - — s~~vsSK^«^YW^n'Wvw^^ 



TONIC PHASE CLONIC PHASE 



i/^^vvvwlAl , '^^%o^^J^^*^v^^ — -— — -—^^ 



,V\^Vl/YVVYV\/VVVVVVV'V' , ^^ — 



■v - 



jijuu»-a^a^juxJUau 1 ^xajuju4^Ji~_A~-ji A j^ — uj~jujluuJU-UX-L_ ui. — * 



a^_ji. U^Jl^-A^-A^X^-L^L-J A — (-_X— i- — t — L— A~ 



— Aft_-A/s- -L> h> JL— — A^— Ls— Aa— Kr M K 



I '*« I XXI*" 



^nAnAAnAA^jmniWJWV\fWV, AAAj . ... ^ajw^ — -I 



^mmmmmmw^m?, i ' imam vwv — -i 



ooened eyes- s'ored 



300 M" 



11.. 1 1 Mi, record oi .1 minor petit mal seizure showing characteristic 'spike-and-slow-wave' 

 sequence. The attack lasted about 14 sec. Consciousness was in abeyance, and there was amnesia 

 foi the attack. From Lindsley, unpublished observations. 



I hese workers have also demonstrated that disten- 

 iKin of the carotid sinus, with experimental control 

 hi arterial pressure and cerebral circulation, is capable 

 (if inhibiting liy nervous transmission the brain-stem 

 activation ol the cortex. This is the only known 

 met nanism oi afferent influx to the reticular formation 

 which inhibits it, and ihus reduces cortical activation 

 and promotes slow-wave development comparable to 

 thai in .1 si. iic (il sleep. The influence ol sympathetic 

 tone as an activator ol the ARAS, oi the sudden drop 

 in tone as a deai tivator, may under certain emotional 

 in fatigue conditions be able to induce either accen- 

 tuated hypersynchrony and fast activation waves 



such .is appear to trigger the grand mal attack and 

 produce unconsciousness, or else slow waves which 

 also are frequently associated with unconsciousness. 

 The carotid sinus mechanism and its inhibitor) effect 

 on the ARAS may well be a participant in uncon- 

 sciousness produced in seizures, syncope and narco- 

 lepsy 



Gellhorn and collaborators (23, »<>, 88) have 

 emphasized the relation of the unspecific to the specifii 

 sensory systems in relation to perception, attention 

 and consciousness, Gellhorn (86) feels that interaction 

 ol impulses from the diffuse, hypothalamic-corticaJ 

 projection system with (hose of the specific projection 



