Hungarian EEG society

ELECTROENCEPHALOGILAPHY AND CLINICAL NEUROPHYSIOLOGY

SOCIETY

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PROCEEDINGS

H U N G A R I A N EEG SOCIETY Budapest, February 8-9, 1963

Secretary: DR. P. JUH/~SZ Neuropsychiatric Clinic, University of Debrecen, Debrecen 12 (Hungary)

1. Reerultin8 potentials and conditioning. - - L . AntLvln, G. T. ~tkldulina and E. Grasty/m OP&~s). Experiments were carried out on fifteen cats with chronically implanted electrode~ in order to analyze the influence of two psychologically different situations of avoidance conditioning on cortical recruiting responses (g. proreus, g. Sul~rasyivius)elicited by stimulating median thalamic structures (n. reuniens, c. medianum). The second aim of the study was to establish whether stimuli eliciting recruiting potentials can be used as conditional signals, and to analyze the changes in recruiting potentials appearing during the formation of the conditional pgocL~J.

It was established that recruiting potentials characterized by prominence of the surface negative phase suffered a marked decrease of amplitude when the cat stayed on the place of reinforcement (shocking grid) compared to those elicited on the place of flight (a small bench), or when the potentials were elicited simultaneously with the application of the conditional stimulus, lntwo animals with potentials characterized by a first surface positive component an opposite effect, marked increase of amplitude of both positive and n©gativecomponents, was obmervedin the same conditions. Marked differences were found between the elaboration ofconditinning using two different kinds of recruiting potentials, in :he case of stimuli producing pure surface negative potentials ~ relatively large number of reinforcemeats was needed to establish conditioning, the conditional reflex appeared only after the cessation of stimulation, and the reflex remained always unstable. In the case of recruiting potentials contaminated with prominent surface positive components conditioning was formed sooner, the reflex appeared during the application of stimulation and it was more stable. A direct inhibitory action of pure surface negative recruiting potentials could be demonstrated by twoconsecutive stimulations. In this case the conditional reflex appeared only after the cessation of the second train of stimufi with the same latency time as it would have appeared after a single train ofstimuli. The assumption is discussed that different parts of the thalamic diffuse projection system represent different mechanisms, and that the recruiting potential reflects an inhibitory function.

2. The role of the startle reaction in conditioning. - - E. Grast3~u. ~d F. K U n O q (P,ks). It has been established that, similarly to sound stimuli, startle reactions are elicited by conditional light stimuli in an early phase of development of the conditional adversive reflex. At the time of appearance of the startle reactions general motor inhibition, a decreased cortical electrical tonus and an increase of the late surface negative waves of the evoked potentials can be observed. It is suggested that a common mechanism is represented by this potential component, the human "non-specific EEG respon*o" and by the recruiting potential. On the basis of the decreased cortical tonus accompanying the conditional startle reactions the conclusion is drawn that the mechanisr~ of the startle reaction consists in a subcortical irradiation process released from cortical inhibition, The startle reaction is considered as playing an important role in the developement of the conditional reflex and at tho same time as one of the earliest somatic conditional manifestations.

3, I~havloral and electrophyslologiml Itndy of the action of atrophte. -- G. Karma, E. Gmst~n and J, Czopf

(P~). A study has been made on the CNS effects of atropine in cats, with the help of chronically implanted cortical and subcortical electrodes. Atropine in doses I-4 mg/kg i.p. produced a synchronized EEG pattern both in cortical and subc.ortical structures. At the same time the desynchronization, elicited by high frequency electrical stimulation of the mesencephalic reticular formation, was blocked, No spontaneous somatic manifestations, except a semi-stuporous state, were observed during the effect of atropine. Cortical potentials, evoked by low frequency electrical stimulation of the reticular formation, as well as the early positive component of the recruiting potential evoked by stimulating n. ven~r, ant. of the thalamus, were sug.pressed. The threshold of the negative component of the recruiting potential fell, and the amplitude of the potential increased, These data suggested that atropine exerts its action primarily in the brain-stem.

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Single doses of 2 mg/kg atropine destroyed performante in a complex alimentary-avoidance conditional reflex situation. The performance in a multiple-choice delayed reflex apparatus was also reduced to chance level by the same dose of the drug. It is concluded that the widely accepted dissociation between EEG activity and behavior can be substantiated if the action of atropine is analyzed with more sensitive conditional reflex tests. 4. Hgect of bemmm and zylene on the sidke aedv/ty of the ea~wal eertex. -- !. IMsi snd l. NikeHte (Budapest). The omtral effects of small doses of benzene and xylene have been investip~ci in acute experiments, it is known that stimuli influencing the reticular formation alter the spike frequen~ elicited by strychnine on the cerebral cortex. A 2"/. strychnine solution and silver electrodes have been plagod on the frontal lobes ofcats, and bipolar deep electrodes .;n:c the ngzencephelic reticular formation. First the average of "spontaneous" strychnine spikes was determined, then 0.7 and 1.4 ml/kg of benzene and xylene, respectively, were injected intraperitoncally. Thirty minutes after the injection of benzene the cortical spike frequency increased, the increase being more pronounced with larger doses. Xylene elicited an increase in spike frequency within the first 20 min, then decreasing below the spontaneous value. The reticular formation likewise showed a change due to these agents. In many cases the reticular spike series consistently preceded the appearance of cortical spikes. The changes persisted throughout the 4.$ h time of observation. Finally, small amounts of benzene and xylene also influence acutely the appearance of strychnine spikes. The pathological effect probably makes its influence through the reticular formation. Xylem seems to produce more severe chenlm thin benzene. & C h a n ~ in the WBG of rate due to Nund stimuli. !. Nlkollt~ P. Keml, i, IMsl and L, Czabalal (Boda.

pet).

The pouible EEG effects of the general noise level measared in Budapest have been investigated in rats by means of implanted cortical electrodes. The freely moving animals were exposed to .sound stimuli of 1000 e/sac and of 80, 100, 110 and 120 phon intensity resi~'tively, each for 2 h. Before and after stimulation the spontaneous EEG as well as the electrical activity appearing after cortical (occipito.oct.ipital) square wave electrical stimulation were recorded. An increase in the frequency and a decrease in the amplitude of the EEG were found at 80 phon. In response to 100 and 110 phon there appeared also some sharp waves or spikes, and proBrenive desynchronization; 120 phon completed the dasyndtmnization of the background; however, it precipitated intermittent spikes in one Stoup of animals and high voltage delta bursts in another. The desynchronization time after electrical stimulation of the cortex was prolonged by intensification of the sound stimuli, but showed a sisniikant abbreviation when delta bursts were present.

Sound stimuli simulating those measured in the town itself produced transitory paroxysmal manifestations in the EEG; further, they caused some psychomotor inhibi. tion of animals of weak typological t)Ve. No spasm or other kind of change (e.g., changes in adrenal ascorb~;c acid level) was observed. 6. The effect of the ligatleu of eervkal lyml~al/e vessels and lym~ nedes on the EEG. - - F. OI!/I, L Mudsrlsz~ O. T. ZolffmJ M. F61dl (Szepd). Two to 3 weeks after the implantation of chronic epidural electrodes all the lymphatic vessels and nodes of the anterior cervical region ofcats and dogs were lipted. On the 2nd day after this operation short groups of waves at 3-6 c/see appeared in the EEG. Between the 4th to 8th days an increasing percentage of I-6 c/see waves of high voltap was seen in the backip'ound EEG. This back~'ound activity, however, could be desynchronized relatively easily, after a variable latency, during these days. Between the 8th to 20th days the EEG became gradually normal again, although transient slow waves appeared sometimes. 7. The effect of the lhlatlon of the eervkal tymplmfle vmzels aod nodes on the EEG and motor arousal geaelkm. - - I. Mathu/u, F. Ol~d, O. T. Zoltln and M, FSldi

(Su~I).

Before the libation of the cervical lymphatic vessels chronic epidural and subcortical electrodes were implanted in cats (frontal and occipital cortex, mesencephalic reticular formation, hippocampus). By means of electrical stimulation of the reticular formation the threshold paramcters of both the EEG and motor arousal (orientinlO reactions were determined. After ligating the lymphatic channels and nodes both thresholds were daily measured, On the 4th to 8th days following the liption the EEG arousal threshold was found unchanged, or moderately elevated (0-50%). At the same tin3e, however, the threthold values of the motor arousal reaction proved to be significantly increased (66-80~), I.e., the small interval between EEG and motor arousal thresholds, foundin the normal state, became considerably wider after the liption. A similar dissociation of the above parameters could also be brought about by 3.5 n~lqi LarlPtctil. On the basis of these observations the formation of a partial blockade in the polysynaptic systems of the mesencaphalic reticular formation is concluded. $. On tbe l ~ m ~ of the eorti~l s ~ d l u d u ~ tn the cat. - - O. F d ~ , F. MecMer mul P. ~ Observations were made on the surface and in various layers of the ectosylvion and suprasylvian cortex in cats anaesthetized by a mixture of chloralnse and methane. The relationships between strychnine discharges and the potentials evoked by acoustic stimuli or transcalloal electrical impulses were investigated; further, the effects of application of ACh and of GABA on the strychnine spikes were studied. Some topical differences were found in the shalm and voltage of the disdmrge, in tim Imrameters needed for evocation, in the refractory periods and in the sensitivity to these druss. When applied on the

Electroe~'eph. olin. Neurop/wsLol., 1964, 17:335-339

HUNGARIAN ~ cortical surface GABA caused full inversion of the strychnine spike in the superficial layer (200-300p). The spikes appeared, however, with their o~ginai polarity at a depth of 300-,~Op, but showed reversal of polarity in the deeper layet~ From thou; findings it is inferred that the strychnine spikes may have a different~mesis from that of the evoked potentials. Possibly strychnine discharges have their origin in the dendritic network of the superficial cortical lcy~. The large negative wave of the strychnine spike may represent spreading excitation in the superficial cortical layers; the positive wave may signal the returning of synaptic functions at the hyperpolarized synapses. 9. Interrelations between e h e m m ~ l ~ l o g r a l J l e and meter respmum din'in8 tmbltmate sleep In man. - F. gaiter ~ P. H a ~ u (DtC~e~). in 40 patients, aged 10-41 years, EEG recordings us well as measurements of pupillo-motor functions, corneal reflexes and EDG were simultaneously carried out during Evipan narcosis. The EEG responses induced by acoustic, nociceptive, cold, tactile, proprioceptive and internal stimuli were ~orded and analyzed. Certain phases of the narcosis showed definite morphological and biological similarities to those described as "paradoxical" or "rhombcneephalic" sleep patterns. Such stages could be facilitated either by external or interhal stimuli; if present at other sleep levels epileptiform electrical discharges appeared to be inhibited by this pattern. It seems that "paradoxical" sleep is revealed by suppressive and protective activities of some non-specific structures which may he promoted by the sensory input. Peripheral stimuli during falling asleep or lightening of the narcosis elicit various features of the electro-morphological responses. Deepenin~ narcosis is characterized, at first, by "pure desyochronization", later by "doubled responses" ("initial desynchroniz~ttion" followed by "late synchronization"). During very deep sleep responses always fulfil the concept of "pure synchronization". The same type of morphology is oblained in the "paradoxical" phase, also. Lessening of the sleep depth shows a reversed sequence of the electrical responses, namely, initial "pure synchronization", thereafter "doubled responses" and in somnolence "pure desynchronization". The greatest synchronizing effects can he induced by vagel afferents, and by application of cold and pain stimuli; however, stimuli arising in the bladder wall (splanchnic impulses) mainly cause some "pure desynchronization'. Longer trains of delta waves building up a response are usually accompanied by biological signs of some crude, limited awakening process. Pupillo-motor reactivity is very inert compared with that of the EEG; a marked and long-lasting synchroni;,.ation elicited by peripheral stimuli, however, is associated with mydriasis, while evolution of paradoxical sleep involves extreme miosis. The EDG is enhanced by moderate barbiturate effects yet its existence depends on at least minimal orienting responsiveness. The results described above suggest that the various types of "synchronization" and "desynchronization" should have different origins and natures. Further, it

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should be assumed that the non-specific systems of the human brain, being able to influence the electroencephalographic and motor reactivity, have a scale of sensitivities against barbiturate actions. There may exist some hierarchy and antagonisms between these systems, masked in wakefulness but released or suppressed step by step by deepening or lessening of the narcosis. 10. Autommfle paroxysmal d/gurbances assoc/ated with elglepflfom electrical activity h the emtr~froatal regions of c ~ t r ~ . - - F. gajtor. I. O v a , and T. gaszls ~ ) .

Among 132 enuretic patients 60, and 20 out of 22 children suffering from "abdominal epilepsy", were found to show typical epileptiform potentials with pimse reversal at the central electrodes in the EEG during Evipan sleep. Convulsive discharge in the waking state was rarely picked up in the enuretic group althongh spontaneous slowing and irregularity of the EEG was frequent; in the other Woup, however, waking records of nine persons contained sh~A'p waves or even spikes in the central area. The epileptiform activity appeared c~,nt~mporaneously or independently in both centro-frontal areas, with greatest intensity during light sleep. Other kinds of partial or bilateral patterns could he mostly localized to the anterior and medio-bazal regions of the temporal lobe, in seven additional cases. The bladder of every enuretic patient was filled up in the waking state and the influence of great spontaneous changes in the intravesical pressure (micturition) on the EEG during barbiturate sleep was studied. Loss of urine was regularly induced by the deepening narcosis cheracterized by dominance of the delta ranp. Micturition caused, if anything, diminution of amplitude and increase of frequency of the electrical background in varying degree, and was accompanied by mydriasls. The "sleep activation" of firing showed a clear relationship to the enuresis in a few children only. It is thought that the patients producing epUeptiform potentials had a special form of masked epilepsy. The central appearance of tim discharge might reflect sore© functional defects or immaturity in the functions of th~ centre.frontal corto~t pr, !sposing to recurrent disturbances of the regulatory influences on the bladder or the gastro-intestinal tract. 11. The role of the Iocllflmt of brldn-stem danuige in the origin of EEG elumMs. - - R. W-tM and Z, A m l ~ (Budapest),

In ten case~ of tumour directly damaging the brain-stem the clinical, EEG and pathological phenomena were studied. Changes in the state of consciousness and the EEG pattern were only encountered in five cases, where meso.diencephalic section of the brain-stem was effected by the pathological process. In these cases repeated EEG examinations showed slowing down or disappearance of the alpha rhythm. The appearance of diffuse slow activity preceded the clinical signs of increased intracranial pressure, drowsiness and confusion. The desynchronizing effect of intermittent photic stimulation ceased with the appearance of disturbance of consciousness. Turnouts

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destroyin8 the ponto-bulhar structures ($ cases) failed to cause significant difference in the EEG pattern. The alpha rhythm did not chen~, slow potentials did not emerge with the development of papilloedema, hydrocephalus and obstruction. Confusion was only observed in the ~lmge. Our observations, compared with published data, point to the fact that in lemons of the brain-stem the EEG pattern marks reliably the upper (meso-diencephelic) and lower (pontobulbar) limits of the pathological process. The impairment of the compensating mechanisms which sustain the conscious state cause impairment of c o ~ c i o u s n ~ only in an advanced stage of the disease even in chronic cases,On the other hand, acute lesions of the lower brainqtem may be accompanied by immediate confusion, particularly if the damage has a relatively 8rest extent. Thus, whereas the EEG pattern plays a role in the location of the process, changes in the level of coneciomn~5 indicate its dynamics. In cases of both acute and chronic proce5~s we I~Id the ascending reticular system of the brain-stem responsible for the mental confusion, in the acute process, however, the damage is i~robably indirect, whereas in the chronic one the mesodiencephalic systems are directly destroyed. 12.~

of ddlklhe~ ~relx'al tumoun dlapmed by E£G

a l e ~ . - - K, Rilmi (Budatmi),

In two children a space-occupying intracranial process could be substantiated by electroencephalography while clinical and other examinations yielded insufficientresults. in both ~ses the EEG change5 were located in the ternporo-parietal area, which was confirmed at operation. it is thought to be important to carry out EEG studies in order to have an early diagnosis, ©,~enwhen there is only a slisht suspicion of cerebral turnout; the contr!butlon of the EEG may be essential to the su¢~s of surgical treatment ef intracerebral tumours in childhood. 13. Exist'rental electro.stimulatlen. !, Effect ef stimulation on the KEG, ~ T, Haaao#, E. Feny6 sad J. Antal

(Budsl~t).

Partly local and partly bitemporal stimulation has been applied by means of rectangular impulses through scalp electrode5. Electro~.s were arrayed bipolarly for local stimulatinn. The f',~,luency of stimulation varied between 2/see and ,0,00~/se~, the duration of the impu|se~ between 0.03 and I00 msec respectively. The voit~ge amounted to 30 V o.~ averaBe, and stimulation lasted 30-60 sec. EEG rccord~ were taken ilnmediately after stimulation. A total of eigt~,t~n patients was examined. !.~: ~! stimulation i r ~ l an increase of slow activity and ~ appearance of it. :tative fact in patients suffering from i~,tracmnial turnout. Focal manifestations were accentL~d in cases of temporal lobe epilepsy, and an activation of the slLw focus was observed in post-traumatic patients. Bitempoml stimulation elicited centrencephalic seizures in patients having central epilepsy while it activated focal slow potentials and irritative signs in cases showing temporal epilepsy. It is suggested that local irritation is mainly suitable

for excitation of cortical structures while stimulation of the meso-diencephalon is appropriately achieved by bitemporal electrical impulses. 14. Extracrsalal eleclro-sflmulafiou. IL Effect of dectro. sfimulatlea ea the eesinephil cell eeunt. - - J. Antal, T. sod E. Feay6 (Bedal~t).

Changes in the number of cosinophiis provoked by hitemporal stimulation have been studied. Events of this kind are effected by way of the pituitary-adrenocortical apparatus and indicate diencephaHc excitation. Nineteen endocrinologically healthy patients were examined. While unilateral temporal stimulation did not provoke eosinopenia in any of the cases, bitemporal stimulation did so in 55~. In order to eliminate pain as a possible unspe¢i~ stress, stimulation was repeated after the administratio: of iidocaine hydrochloride, yet the result remained unchanged. Administration of the drug without stimulation induced no effect on the eusinophil cell count. Stimuli, the effects of which on the number of eosinophils were separately observed, had the following frequencies: I0, 200, 500 and lO,000/sec. A frequency of 10/see elicited eosinopenia in a significantly larger number of patients than other frequencies. It is noteworthy that many of the patients who did not respond with cosinopenia to stimuli of 10/see displayed acute cosinophilia, a phenome. non which, as demonstrated in earlier investigations by the pre~nt authors, is pre5u,,~ablylikewise of diencephalic origin. As regards the mechanism, there ore various possibilities: (1) impulses coming from the two temples in the case of bitemporal stimulation may pass throullh the diencephalan and exert a direct irritation thereof, (2) hypothalamuJ, reticular formation or some part of the llmblc system may equally represent the primary focus of excita. tion, and abundant interconnections ensure the irritability of both the hypothalamic and centrencephalic structures. lS.Selz,res Wovoked by television, - - F. Fes~dl, R, Frtter and L. SzeSedi (Budapest). Report on the clinical and EEG examination of five patients whose epileptic seizures could be precipitated by TV. In two cases seizures appeared exclusively during looking at the TV screen, while attacks manifested themselves under other circumstancet also. In three patients electrical seizures could be provoked by photo-stimulation. In one case photic stimuli remained without effect while in the other patients photo-stimulation and hyperventilation helped to localize the convulsive proce~.

l~ FJectmm~esraphk ebse~ens on redpme~ luterm. Uon. -- M . Neueesel (audapm~ Littleand short electricalactivityappeared above the m. latissimusdorsi at the beginning and the end of a simple lifting of the arms. Loading these extremities, however, was accompanied by an intense electrical activity during the whole exercise. In the course of the highly coordinated flexion of the fingers there was a dear-cut electromyowam from the common extensor muscle of the arm. Thus it is shown that, during the movements, not only the agonists

Eiee:roenceph. clin. Neurophysiol., 1964, 17:335-339

HUNGARIAN EEG $OCi~t'Y but also the antagonists are activated, although in different degrees, a.,'~ ~t.he.r :yn-~,rono~ly or a~ynchrcnou~!7. Antagonists exert an important modulator action on the agonists; with incr.~sing activation of the agonists the 0articipation of the antagonists is also extended. 17. An ~ - - O. ~

etrhe mowments ef the fmga's usf~ EMG. and M. Nemessuri (Budapest).

Voltages of the spikes recorded from lumbrical and dorsal interosseons muscles during isolated flexion and extension of the fingers show much greater values than those picked up from the finger muscles of the forearm. It is supposed that this difference has its source in the sensory feedback mechanism which regulates the contractions of the forearm muscles, using the afferent irapulses derived from the hand muscles. Learning fine finger movements results in building this "feed back" system. At first, muscles having ~. prominent role in the finger movements give signs of

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their contraction and these remain in activation longer than ~ e others. The ~eighbouring interosseous muscles collaborate in the isolated movement. The use of the EMG method may give a differential picture of coordination of muscle activities; its results may be utilized in the process of teaching specialized movements. 18.Paroxymul EEG changes of temperai I o c u l i m ~ in Meni~,-like s,.~adromes.- - I. F~nyu (Budapest). Records of two caseswith Meni~re-like attacks (vertigo, nausea, vomiting, disturbance of gait) were presented. Examinations, including oto-neurological, were negative except for the EEG. In case I appeared high voltage theta bursts and spikes in pha~ reversal in both temporal leads; in case 2 sequences of high voltage 3--4 c/see waves were recorded in all leads. The EEG abnormalities were of paroxysmal character in both patients.

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T H E EEG SOCIETY London, October 12, 1963 OFFICERS FOR

1963-64.

E. A. CARMICHAEL W. A. Conn M. V. DRIVER W. A. KI~NNi~D¥

President: Chairman of Council: Treasurer: Meetings Secretary:

Secretary and Foreign Secretary:

P . B . BRADLEY

The Medical School, ,~'irmingham15 (Oreat Britain) I. Some EEG ohservatlons on children with Infantile Slmm treated with ACTH, ~ Ruth Harris and G. P m p ~ i e n e (Londen). Between 1959 and 1962, 84 children with "infantile spasms", referred to our Departn,qent for EEG studies, had at least one course of ACTH. When serial EEGs had been taken during treatment considerable individual variations were noted. However, in general, the following sequence of events occurred. With one exception, no substantial change was seen before 3 to 5 days; by 7 to 10 days there was an over-all diminution in the amplitude of the irregu. lar slow activity and in the discharges. When the dighar. get seemed to have disappeared during the waking state, they might re-appear during sleep, either spontaneous or induced. P~hythmic activity began to appear only weeks after discontinuing ACTH. In some cases the EEG features were not substantially altered, while in others an initial improvement might be followed by deterioration. This sequence of events might be repeated during subsequent courses of treatment in the same patient.

The EEG and the clinical improvement were not parallel in many cases, although the general trend might be similar over a long period. Of the caseswith early favourable clinical and EEG response to ACTH, only four eventually recovered. In the group of sevenchildren who ultimately did well clinically, there were considerable variations both in the clinical and the EEG evolution, although all of them had begun to suffer from infantile spasms before the age of 9 months and had started therapy within a few weeksto 6 months of the onset. Some EEG vJumgm in relation te arterial and venous pressure changes durinll enrdine operatinm. - - Ann Harden (London). During operations on the heart and main vesselsalterations in blood flow through the brain, caused either by a decrease in arterial pressure or an increase in superior vena cava pressure, may cause changes in the EEG. These changes seem to occur atvalues which differfrom one patient to another, even taking into account such obviously important factors as the duration of the pressure changes, the 2.

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