Symposia in the 4th annual meeting of the Japan society of electroencephalography and electromyography

Flectroencephalography and Chn~cal Neurophysmlogy, 1975, 39 539 544 Elsex~er Scmnhflc Pubhshmg Company, Amsterdam Printed m The Netherlands

SOCIETY

539

PROCEEDINGS

S Y M P O S I A IN THE 4TH A N N U A L

M E E T I N G OF THE J A P A N

SOCIETY OF E L E C T R O E N C E P H A L O G R A P H Y

AND

ELECTROMYOGRAPHY ()~aka No~ember 27 29 1974 ,Secretary

PROF

K

NUHARA

o ro~,o Bunl, o 2-28-21 Ho.aomagome Bunk~o-ku. Tol, y,, ¢Japan)

SYMPOSIUM I EVOKED SPINAL C O R D POTENTIAL I

Clinical application of evoked spinal cord potential measurement.I" K u r o k a w a (Tokyo).

The ew~ked spinal cord potential was studmd m 78 subjects by placement ot both stimulating and recording electrode~ m the spinal epldural space rather percutaneously under local anesthesm or directly, under surgmal exposure Chmcal and experimental evidence suggested that the first ot the two negam, e phases m the normal cord potentml was conducted mainly Ihrough a superficml layer of the posterior part of lateral fumculus and the second phase through the posterior lunmulus This method v, as considered to be useful m the h~llowmg chmcal problem~ 0) to confirm preservatmn ol" conducuvlty in the injured segments of the cord m the case of spinal shock (n) to determine the level of conduction block from observanon of posm,,e conversmn of the negatl;'e phase of the action potential, {m) to detect the extent of damaged cord area by examination of changes m the v, ave shape on the exposed dura mater during surgery {ix) to measure lhe mtramedullary conduction velomty (mean values of the hrst and the second phases were 73 _+9 4 and 47 + 1 I m,~ec respectl',ely) (v) to momtor, without mterruplmg surgical procedures conductivity of rele'~ant segments of the cord to detect possible damage to be caused by surgery 2.

Climeal utilization of the evoked spinal cord aetmn potential in spree and spinal cord surgery. - - T. Tamak~ and T. Y a m a n e (Ch~ba).

The amphtude change m the evoked spinal cord action porchhal ~s regarded as an mdmator of physiolog~cal spinal cord actl\lty Experimental and chmcal studms were made to evaluate the po~sxbxl~ty of apphcatmn of the above concept as ,me monitoring method to avoid latrogemc spinal cord injuries by' wine and spmal cord surgery To monitor the cerxlcal spinal ~ord a recording electrode ,,',as inserted m the c~sterna magna and electrical st~mulatmn was g~ven to me&an or ulnar nerve percutaneously at the level of the w'nst joint The recorded acnon potential was polyphas~c and of decreased amphtude m cases of compression of the cer',mal spinal cord

Thoracic level spinal cord actl,~lty ~ as observed by means of specmlly made electrodes One is a stimulating electrode put at the upper thoractc level m the extradural space The other is a lumbar electrode threaded into the subarachnmd space close to the conus medullarls The elecmcal shmulatlon used was 30 c,'sec 20 30 V, 0 3 msec duranon The 200 300 acnon potentials recorded from the canda equma ,acre averaged by means of a computer The action potential consisted of an mmal spxkc followed b? polypha~lc v~a~es From our observat~on~ m cases of fresh spinal cm d injuries, the conclusion was reached that the polyphaslc x~a'~es correlate well v~th skin sensanon 3

The e~oked ~pinal electrogram recorded from the epidural space m man - - On the origin of the P2 ~a~e K. Shlmop (Nngata)

The evoked spinal electrogram (ESEG) produced m the epldural space by several modes of peripheral nerve stlmtdatlon ,aas studied m man With single shock stimulation the E S E G consisted of mmal positive spikes (P~) follox~ed b.~ slow negative (N I ) and positive (Pa} waves They' were ~lmflar to those reported m decerebrate ammals By graded stimulation the amphtude of P2 reached maximum far earher than that of Nt or PL The "second" component of Pz was ehclted by a stronger stimulation or excitement of the subjects With brief trams of repetitive pulses (up to 10 at ?,50 c,sect P, maintained duration much the same as that evoked by single ~hock shmulahon With more prolonged stlmulanon P2 mvreased in duration with several summits The tnne-course ~1 P2 ,aas shortened by the condltmmng volley to the same nerve Two mteractmns were observed inhibition or occlu.~on by strong stimulatmn, and facflltatmn by weak sumulatam between P2 waves produced by the tlblal and common peroneal nerves Functmnal orgamzatmn of the human spinal cord was discussed in terms of the primary afferent depolarization related to Pz 4.

Spinal evoked potentials recorded from surface electrodes (Discussion 1). - - T. N a k a n i s h i (Tokyo).

Summated evoked potentmls to medmn nerve stlmulanon were recorded from surface electrodes placed over the upper

540

SOCIETY PROCEEDINGS

cervmal spine The responses consisted ofbtphas~c or trlphaslc potennals Thmr shortest latencms averaged 12 msec In 2 patients with sensory deficits due to bram stem lesmns, no cortical responses to stimulation of the affected side were obtained, but a response to median nerve st~mulatmn on the affected s~de was recorded from surface electrodes placed over the upper cervical spine These findings m~ght suggest that these potentials arise in the afferent path,,~avs of the upper cer'dcal cord 5.

Physiological basts of the evoked potentials in the spinal cord (Discussion 2). - - T. Hongo (Tsukuba).

Based on data from ammal experiments findings were reported on the evoked surface potentials of the spinal cord in mammals with respect to their electrophysmlogmal properties and the origins and sources from which they were e*,oked ]['he following kinds of potentials were dealt w~th (1) those evoked by various afferents In the peripheral nerves and recorded at the enlargement region of the spinal cord of their mnervatlon (2) those evoked by antldrom~c volleys in motor fibers and recorded at the involved segments, [3) those evoked from varmus kinds of afferents and recorded at the nonenlargement regmn of the cord of the upper level_ (41 those evoked by stlmulauon of the dorsal, dorsolateral and ventrolateral surface of the cord respecm, ely, and recorded from different levels of the spinal cord including both enlargement and non-enlargement Further. some comments ,aere made on the caution that must be taken in interpreting the spinal ~ord evoked potentials

2

Developmental disturbance of the brain - - based on neuropathology of severe cerebral p a l s y . - Y. Monmatsu, T Shmohara, H. Matsuyama. M. Funabashl, K. Tamagawa and H. Sasaki (Fucbu).

1 32 se,~ere cerebral pals) cases ~ere classified into three groups (A, B and C) based on neuropathologlcal ohservatlon Group A was characterized b~r destructmn of the blain Fwenty cases originated m the permatal or postnatal period Group A J~ focused m this presentation Predominant findings m group A aere a~ l'ollo~s cystic brain ~del.~ spreading sclerosis ol the ~h~te matter atroph} ol the anterior half of the cerebrum, status marmolatus of basal gangha, marked changes of the thalamus and se'~ere deterioration ol the cerebellum 3 "lhe cystic brain and wide-spread ~cleroqs of cerebral v~hlte matter demonstrated chmcally an acerebrate state and a flat EEG or slow wa,,e dysrh_~thmm tktroph.v of Nmmon's horn and determratlon ol the dorsomedml thalam~c nucleus ma} correlate ,alth mental retardation 4 In the thalamus, the dorsomedml nucleus and dorsal or medial portmn of the lateral nucleu,~ ~ere predommantl) revolved Non-specific thalam~c nuclet ~ere better preserved than specific nuclei 5 In the brain stem. mfantde spasm cases demonstrated atroph.'¢ of the pons and mldbram and d x smyehnanon spong y s t a t e a n d g h o s t s m l h e t e g m e n t u m Ner~ecellswererelaUvel.~ well-preserved

3.

SYMPOSIUM II. DEVELOPMENT OF THE CENTRAL

The EEG aspect of the normal and abnormal development of the central nervous ~ystem during earl,, hfe - - K. Watanabe (Kasugai),

qERVOUS SYSTEM AND ITS DISTURBANCE I.

Morphological studies on development of the ner~ ous system - - congenital anomalies. - - K Nakamura (Kobe).

1"he critical period of congemtal malformanon of the CNS can be seen in all stages of organogenesls histogenesis and functional maturatmn Th~s paper discussed morphological dffferenUatlon of malformatmns of the brain 1 O~ganoqenem (a) Generally, anencephaly is caused by reopening of the nemal tube and e~encephalus however occasmnally it may originate from holoprosencephaly One of the typical signs of human anencephaly is area cerebro~asculosa which is abnormal ,,ascular proliferation m the CNS from the telencephalon towards the spinal ~ord (b) Each type of holoprosencephaly was classified accordine ~,~ ~tructural abnormaht) of the brain which IS seen m saglttal, transerse and horizontal cleavage failure 2 Ht~toqeneml (a) Heterotopy ofneuroblasts and spongmblasts The origin of the cells in the telencephalon and cerebellum ,~as studied from the point of maturatmn and migration m the matn~ (b) Experimental core formation in the rat-fetus brain was compared w~th human porencephaly ]'he large core formatmn caused porencephaly and the small one could also lead to minimal brain damage 3 Hvd~oeneephalodv~pla~la This is one of the typical combined types ofcongemtal brain malformanon "I he ortgm of electric actr~,lty was ,,tudled in the I [ (, of the malor b~am malformaUon

1 The maturatlonal changes of E EG visual e,, oked potenUals (VEPs) and auditory evoked potenhal~ {AEPsl during the last 16 weeks or" the intrauterine hfe were described 2 ]-he neonatal E F G findings m the following &sorder~ were reported (a) Anencephab {b) H.xdranencephal_~ "~ pol} graphic study re'~ealed t~o phase~ oI sleep active and quiet although the EEG waslsoelectnc In one case an AEP was obtained from the left temporal area v~hfle VEP ,,,~as absent (c) Congenital hydrocephalus ~Jth agenesls ofcorpus callosum, arhmencephaly and hypoplasla of the optm nerve (d) Holoprosencephaly Although the EEGs m the neonatal period ,~ere highly characteristic and abnormal, the ~,EP and AEP shorted a normal ~,,axe form consistent ~lth the conceptional age (e) Cerebral dysplasla (ll a case ,alth abnormal cellular architecture of the cortex (li) a case ~lth septum pellucldum cyst 011) tuberous sclerosl> (f) SFD infants 0) hypoplasnc infants such as Cornelia de Lange syndrome (hi infants oftoxemlc mothers The EEG shinned dela)ed maturation v~hde the V E P a n d AEP were usuall) normal (gl Developmental retardauon due to pennatal &sorders

4.

EEG findings in inborn errors of metabohsm. - - K hnuma (Sendal).

In phen)lketonurla delta-dominance ot basic ~a~es became most remarka ble when the peak of serum phenylalan me lex els

541

JAPAN EEG AND [,MG SOC1EFY ,~ as o b~erx ed after lhe phen5 lalanlne load In hyper~ ahnemla the kF(, abnormahtles, such as spikes, were llnpio,`ed after feeding a low ,,'aline diet, but were aggravated on an unrestncteddtet lnthesedisorders thebramdysfunctlonseemed to be based mainly on e~.cess of metabohtes In vltamm Bo dependent convulsions soon after administration o f w t a m m B~,the paroxysmal discharges &sappeared It wa~ thought that. in this disorder, both excess of glutamate and lack of GABA might cause brain dysfunction In phosphorlbosyl pyrophosphate synthetase deficiency hypsarrhythmla of the EEG was improved after admimstratxon o f A C T H i m . and activity of this enzyme w as increased simultaneously One of the effects of ACTH on hypsarrhythmla seemed to be based on an Increasing enzyme activity In Tay Sachs &sease. there were the following EEG findings low amplitude fast waves during early stage and slow v, aves mixed with seizure &scharges appeared after about 1 year. EEGs tended to be of low voltage after about 2 years and the EEG became fiat later In globmd cell leukodystrophy, EEGs were almost normal during the early stage The slow wa,ms gradually increased in amount and were accompanied by seizure discharges as the progress of the illness developed 5.

A stud) of developmental abnormality in motor functmn, especially on the change of stretch response in cases of cerebral palsy --- K. Ishihara and Y. Okada (Fuchu)

The stretch response by manual stretch of limb muscles was recorded by E M G 95 cases diagnosed as cerebral palsy were e~amlned a total of 319 nines The first examination of each case was made within 12 months after birth followed by more e~ammatlons at regular mtervals for at least 3 years An abnormal stretch response first appeared around 18 months and this pattern continued thereafter Abnormal discharge with athet OSlSand 'or chorelc movement also appeared around 18 months to 2 years The abnormal discharge pattern was fixed in some cases and continued throughout thmr childhood SYMPOSIUM lit 1

ANALYSIS OF THE MOVEMENT

Preferred hand and set-dependency of reaction time. - R. N a k a m u r a (Fuchu).

Since the determlnauon of handedness is chmfly based on preference, there must be a difference in the motor function between left and right hands To explore this problem, we analyzed the reacnon time (RT) of biceps in left- and righthanded subjects, using the E M G as an indicator The task was to flex or supinate both forearms simultaneously m res ponse to a sound stimulus with a warnmg signal The analysis indicated that RT ofsuplnatlon was faster than that of flexion, flexion of the non-preferred hand was faster than that of the preferred one and suplnation of the preferred hand was faster than that of the non-preferred one In flexmn the RT was shol tened by extension of the elbow', and thxs tendencs, was more obvious in the non-preferred hand If the stimulus was given without a warning signal, the shortening of RT In an obtuse elbow angle was not clear RT depended upon the posmon and the experimental condmons Thmr effect was stronger m the non-preferred hand These factors had more

effect t h e n the response was performed m an msplrator_~ phase and in non-alpha phase of EEG Thus we can sa~ that the RT of the preferred hand is less mlluenced by set than is the non-preferred hand 2.

A blomechanieal analysis of primate locomotion. --- M Okada and S. Kondo (lnu)ama).

Blomechamcal features of bxpedal walking were analvTed in chimpanzee, gtbbon, baboon, Japanese macaque spider lnonkey and man EMGs of the lower hmb muscles and threedimensional foot forces were recorded during ,`oluntar} bipedal walking of the subject Simultaneous 16 mm motion pictures provided information on joint motion durauon of stance and swing phase and details of the foot action Lower limb muscles in non-human primates exhibited remarkable E M G actlVltmS which appeared almost synchron o u s b throughout the stance phase w lthout an.~ discrete burst a~ strike and push-off as is seen in man lnsufflcmnt push-off in non-human primates was also indicated in the sagLtt,iI component of the foot force Different blolnechanlcal patterns, i e chimpanzee/spider monke.~ pattern and baboon, Japanese macaque pattern, were classified in non-hmnan primates according to the cycle and relative stance phase durauon, knee joint motion EMG actlvmes m the lo~er hmb muscles and vertical component of the foot force Gibbon was characterized by an equivocal pattern These findings were briefly discussed m terms of the e,,olutlonar> aspects of bipedal locomouon 3

Control of quiet standing in the quadrlped (dog) and in the biped (man). - - S. Mori (Asahika~,,a).

The maintenance of quiet standing posture m the quadrlped and in the biped is achieved by continuous minor corrections of the posmon The force exerted by each foot against the supportmg surface was recorded as oscillations of varmus amphtudes and frequencies with use of a force transducer The pattern of the force was consldeled to be one of the external manifestations of the system that was suppoaed to function as a feed-back control The normal adult human foot is arched in coronal and saglttal planes in standing This structural feature of the foot permitted recordmg of the vertmal forces exerted b> the anterior which corresponds to forelimbs in the dog and posterior p o m o n s of the foot separately The higher frequency ripples with a peak around 8 c,'sec {amphtude 0 5- 1 0 kg) were superimposed on the slower shifts of parual wmght m the saglttal axis of the foot and phase-locked with synchrorazed burstmg discharges of the mceps surae muscle The characterlstms of the synchromzatmn of the motor units of the soleus muscle were analyzed on the basis of the statistical parameters of the successive lntersptke intervals The results supported the suggestion that OSclllatmn in the stretch refle,~ loop produced both high frequency oscillations of the force and the grouped discharge of motor units 4.

Contribution of the cerebellum to the neuronal rhythm in locomotion - - M Udo (Osaka).

Stepping mo,~ements were induced in thalam~c cats v, hose four limbs were driven by a treadmill The neuronal actl'~lty

542

SO('ILI-Y PROCEEDINGS

ot this preparation was averaged in relation to the stepping rhythm During a cycle of stepping, most Delters neurons controlling the lpsilateral h m d h m b showed two peaks of neuronal actlwty, the first peak in the stance phase of the lp,qlaleral hmdhmb and the second in the stance pha~e of the lpsilateral torehmb Both peaks started to rise 150 50 msec before the respective limb was placed From the result~ of procedures in which movements of either hind- or forehmbs were stopped, it was presumed that the first peak was derived from active movements of the hmdhmbs and the second from active movements of the forelimbs Neuronal oi ganizatxon m the cerebellar cortex was postulated to conmbute to these peaks on the basis of two lines of experiments (1) analysis of activity of the cerebellar Purkmje cells with long corticofugal axons. (2) changes in the neuronal actl'~lty reduced by selective localized lesions in the cerebellar cortex 5.

Analysis of the gait m o v e m e n t and its c h m c a l application. - - S. O k a z a k l (Kyoto).

An attempt was made to analyze gait quantitatively so that it could be used to measure dlsablhty of the patient and the effects of therapy Histograms of their gmts were investtgated and compared m 10 men with normal function and 10 patients Conclusion In a control group no difference in the peak of the histogram was found, but after the knee was fixed on ~me side there w as shortening of the latent period of the fixed Mde In the patients with osteoarthntlS of the right hip, the latent period of the right side was found to be shortened and m the other side was prolonged In the patients with spinal diseases and cerebellar diseases the difference between sides was not clear but the distributmn of the histogram was clear From the data presented, the analysis of the gait mo,,ement could be used as one of the simple methods to measure quantitatively the disability of the patient

inputs to fast PT cells and an uicrease of the excltator', inputs to slow PT cells The functional meaning of the declease of fast PT cell firing would not be an Inhibition of the cellular at.tlvlly but a gate control to the excitatory inputs since responsiveness of the fast PT cells to both cortical and VPL stimulation was not depressed during arou>al 2

I

Sleep and neuronal activity - - S. Tort,, S. lnuhnsht and T- O s h l m a ( T o k y o and Fuchu).

Mechamsms underlying the changes In spontaneous neuronal firing during the sleep-waking cycle were investigated by observation of the mtracellular membrane potential An attempt was made on pyramidal tract (PT) cells using unanesthetized brain preparations which could display both sleep and waking states Changes in the membrane polarization of PT cells were composed of spontaneously occurring excitatory (EPSPs) and inhibitory postsynaptic potentials (IPSPs) with unitary nature Separate measurement of occurrence of these PSPs enabled us to quantify the excitatory and inhibitory incoming bombardments onto the cell during the state In question Fast and slow PT cells behaved differently During spontaneous or reticular-evoked EEG arousal reactIom fast PT cells showed a decrease of firing rate with the membrane hyperpolarlzatlon caused by the decrease of unitary EPSPs Meanwhile, slow PT cells showed an increase of firing with the membrane depolarization resulting from increased g PSPs Thus, main events on arousal were depression of the e'~cRatory

M

Toru

The conditioned a,~oldance beha,,tor m a Skinner Bo,~ was introduced to deprive both N R E M and REM sleep of rat,, The experiment always started at 9 30 In the morning The 24 h total sleep deprivation produced decreased 5-hydroxytryptamme (5HT) in the dlencephalon After a short period of sleep following the total sleep d e p m atxon_ the decreased 5HT le,~el rapidly' increased and surpassed the control level A simultaneous increase of 5-hydro~ylndolc acetic acid (5HIAA) m the same brain area showed an increased turnover of 5HT m the dlencephalon ~hen the rat had a short period of sleep The increased rate of 3H-5HT formation from lntraventncularly injected -~H-tryptophan (3H-l-r_v) alter a 15 rain sleep following the total sleep deprl,~ation supported the changes of endogenous 5HT The increased formation ot 3H-5HT and 3H-5HIAA in the thalamus was found when ~H-Try was given mtraperltoneally An increased accumulation of'~H-Try In all the brain areas especmll) m the thalamus, was found simultaneously One possible mechanism Inducing dally rhythmmlty of the sleep waking cycle might be an extracerebral factor such as concentration of serum-free tryptophan which influences the synthesis of brain 5HT Another poss,ble biological clock might be a dad3, fluctuatmn oftyroame hydro\ylase in locus coeruleus where catecholamlnergxc neurons play a regulatl'~e role m the brain lndolamme metabolism 3

SYMPOSIUM IV RECENT SLEEP RESEARCH

Brain m o n o a m i n e metabolism and sleep, - (Tokyo).

Abnormalities of R E M sleep in narcoleptlcs and in acute alcohol-psychotics. - - Y Htshikawa ( O s a k a ) .

Sleep satlahon m 24 narcoleptlcs and 10 normal subjects showed no significant difference m both the total sleep time and the REM sleep percentage Sleep of narcoleptlcs with auxiliary symptoms (cataplex) sleep paraly'sls and/or hypnagoglc hal[uclnauon) was unstable, accompanied by a decreased amount of stage 4 and REM sleep frequently occurred at the sleep onset The tendency m narcoleptlcs to fall asleep in the daytime may be due to a certain abnormahty in the neural system for waking The neural ~ystem for N R E M sleep may also ha~e abnormality in narco[eptlcs with auxiliary symptoms Probably because of these REM sleep occurs at the sleep onset Nocturnal sleep was examined In 23 alcohohcs with dehrmmtremens, acute alcohohc halluclnosls or only abstinence syndrome within 1-2 weeks after withdrawal The percentage of REM sleep was smaller in the 3 groups than m the normals A pecuhar sleep state (stage I-REM) with the EEG similar to that of stage 1, tonic EMG discharge and rapid eye movement was found in the patients with dehrmm Stage I-REM may be due to dissociated occurrence of phasic e,~ent,, ol R EM sleep Previous in,instigators have reported abnormally

543

JAPAN EEG AND EMG SOClE'[Y increased amounts of REM sleep in patients with dehrluin tremens, but this might be due to confusion of stage I-REM w~th REM sleep 4.

Treatment of narcolepsy, a REM sleep disorder, with psychotroplc drugs. - - Y Takahashl (Fuchu).

In the pharlnacotherapy of narcolepsy three groups of ps)chotroplc drugs with different effects on sleep were chosen according to the target symptoms Cataplexy, sleep paralysis, and hypnagoglc hallucinations are considered to be special forms of the sleep-onset REM period and fractmnal or dP,SOClated manifestations of the R E M sleep process And they are referred to as the narcoleptic symptoms related to REM sleep These symptoms are suppressed by trtcychc antidepressants which have a REM suppressing effect, such as clomlpramlne, lmlpramme, deslpramme, and protrlptyhne Such psychost~mulants as methylphenldate are very effective in sleep attacks, but less effective In cataplexy Nocturnal disrupted sleep is ameliorated by the neuroleptlcs ~lth a hypnotic effect, e q , chlorpromazlne or by hypnotics e q, barbiturates The clinical efficacy of each drug IS comparable to the findings from polygraphic sleep studies using the drugs We reported that the twice-a-day napplngs of 1 h duration each could be used as a screening test of therapeutic drugs for narcoleptxcs 5

Quantitative analysis of REM sleep in normal human subjects (Discussion 1) - - Y. Morita (Tokushima),

The frequency and occurrence of eye movement during REM sleep were measured m 6 healthy adults By means of an eye movement analyzer devised by Verchere et al (1973, unpublished) REMs were automatically detected and then analyzed w~th a computer The results of the REM analysis of 55 samples of REM sleep recorded In 13 nights in these subjects were as follows The REM sleep time and the REM frequency greatly varied from among the subjects The average tended to increase graduall 3 according to the order of occurrence of REM sleep In one mght The REM interval histogram showed a peak at 0 64 sec The frequency of REM episodes increased as the subjects became more famdlar with the sleep laboratory environment The subjects had 3-6 periods of REM sleep In one night, and the most often was 4 times The cumulative REM sleep time and REM frequency Increased non-linearly In accordance v, lth the occurrence of REM sleep These methods may be efficient for a comparative investigation of quantitative REM analysis Further studies are reqmred to elucidate the influence of familiarity with the environment over the REM frequency 6

Dissociation between the tonic and the phasic events during REM sleep by the administration of some neuro-active drugs (Discussion 2) - - H. Hata (Tottori).

Percent REM permd for total sleep time (°oREMP) and REM density were measured to evaluate the effects of four neuro-actwe drugs, 25 mg chlorpromazme (CPZ), 25 mg

lmlpramlne lIMP), 5 mg mtrazepam (NZP) and 200 mg amobarbltal (AMOB) on the tonic and the phasic events during REM sleep 25 mg CPZ slightly increased ",,REMP, but had no significant effects on REM density IMP of 25 mg moderately decreased ",,REMP, whde ~t had only a transient depressant effect on REM density 5 mg NZP sllghtb decreased "oREMP and moderately decreased REM density and 200mgAMOB shghtly decreased ° oREMP and markedb decreased REM density These findings indicate that the tomc and the phasic events during REM sleep do not always show a parallel change but show a kind of dissociation by the administration of some neuro-actlve drugs They also suggest that the mechanisms regulating these two types ot events during REM sleep are partially different SYMPOSIUM V THE NEUROPHYSIOLOGICAL BASIS Ol~ THE MENTAL FUNCTION FROM THE VIEW OF THI STUDY OF HUMAN WAVES 1. Vertex potential during various mental activities In man. - - M. Shimokochl (Osaka). Effects of mental activity, such as attention discrimination learning, judgment, etc upon V-potential were investigated m normal adults l Discrimination learning was performed using as the CS, tv, o kinds of 4 flicker stimuli with shghtly different frequency assigning V-potential to 4 flicker stlmuh Et E z l~ E4 m order In each trial N I P 2 amphtude (NIP2) showed the tendency of E I > E 4 > E 2 = E 3 The negatwlty of N~ from the baseline was augmented in E t, while In E 2 and E 3 ~t was reduced and the posmvlty of P2 was augmented The latency of N~ and P2 of E L was prolonged about 20 msec and that of E4 about 5 msec 2 When 1000 c, sec, 25 msec pure lone was used, the anchor and context effect on the N~P 2 were examined respectively The N~P2 showed better correspondence ~lth the subjects'judgment than with physical value of stimulus When lever-pressing was simply performed to the tone as soon a~ possible v,~thout judgment, N~ latency was prolonged and Nt negativity was prominently augmented 3 The following characteristics were observed concerning V-potential caused by command stlmuh whmh evoke attention. discrimination and motion In attention Nj latencx was prolonged and N~ negativity was augmented and P: posltlvlty ~ as reduced Conversely, N ~negatwlty was reduced and P2 posmwt3 was augmented m discrimination and motion 2.

A study of the readiness potential.-- K. Iwase

(Nagoya).

By means of chronological data storage and reverse computation of the human EEG, a slow surface negative change preceding voluntary movements (readiness potential, RP) has been described (Kornhuber 1964) Voluntary human saccadlc eye movements and hand movements were studied, the RP preceding such movements was maximum at the vertex Dlstrlbunon of RP &ffered between the hand and the eye The RP increased with mtentlonal engagement It became

544 reduced after a long time experiment when the subJeCts got tired The amplitudes of RP of right-handed subjects aere slgmlficantly larger in left hand voluntary movements than m right ones As for rapid balhstlc voluntary hand mo,,ementb. RP started about 0 8 sec prior to the onset of the movement. ,a htle in the case of slow smooth movements it preceded the movement b3, 1 5 sec This suggests that it takes more time to prepare for voluntary smooth movements than for ballistic. lerks In mentally retarded and convulsive disordered children RP was also studied The onset of RP in the children was relatp~ely earlier than in normal adult subjects The maximum amplitude v, as observed on the precentral region contralateral to the moving hand, but was scarcely observed on the verto, The convulsive disordered children may take more tmae for preparation of simple voluntary mo;ementa 3.

Speech muscle acttwty during dreaming and verbal hallucination. - - A. Shimizu (Osaka).

1 In 17 normal subjects, phasic E M G discharges ~ere frequently recorded from four speech muscles during dreaming m which, as later recalled, they had spoken (not the sleep talking) On the contrary, discharges were seldom found m the dream without speaking The results may suggest that the subject speaks In the dream using subvocal speech 2 In 9 chronic schizophrenic patients, the increased E M G activity of the speech muscles was observed when they had verbal hallucinations whmh were mdmated by pressing of a mlcroswttch by the patients The starting time and the duratmn of increase of EMG discharges corresponded positively ~lth sv, ach pressing This may suggest that the sub;'ocal speech is produced at the moment of verbal halluclnatmn

SOCIETY PROCEEDINGS In the~e patients it ,*as found that the amplitude of the \lsuall) e;oked potential was less and the motor reaction time to the flash 'aas longer ~xhen the stimulus ~as given m the presence of increased EMG activity of speech muscles than when It 'aas absent It ~as inferred that the level ol attennon was lowered during verbal hallucmatmn 4.

Basle rhythms and evoked potentials in attennve states - - H. Suzuki (Tokyo).

Basic or background actp~xtles and evoked potentials were examined statisticall) in relation to some "'attentive states ' 1 Alpha hlockmq and attemion In the EEG of normal subjects, tv, o types of spectral components in the alpha fiequency band one bemg closely related to Ihe visual function and the other having no such apparent relation - - were abohshed or markedly attenuated under dlummatlon or sound sumulatlon Thus, "alpha blocking" may be unselecuve of both affecting stlmuh and the affected components And usual marked alpha blocking by ;tsual stimulus may be regarded as the result of the dominant role of the visual function in man 2 Evokedpotentlal~ and selecm e attention Through apphcation of the Student t test to the amphtude of evoked potentmls recorded in the s~tuanon ot selective attention (key pressmg), noticeable changes were found m the later course (more than 200 msec after stimulation) ol responses m the central and parietal regions The changes were not so clear at the region specific to the stimulus (occlput) It seemed that the amplitude increase of wsual evoked potentials Is not an essential change in selectvm attention and that direct relationships cannot be observed between the basic or background rhxthms and selective attentmn