Marcel Monnier

Les systèmes cholinoceptifs cérébraux — actions de l'acétylcholine, de la physostigmine, pilocarpine et de gaba

Abstract The action of parasympathico-mimetic drugs (acetylcholine, physostigmine, pilocarpine) and of GABA on the spontaneous or evoked electrical brain activities has been analyzed with the technique of Monnier and Gangloff (1961). These drugs, injected in the common carotid artery, produce the following electrophysiological alterations: ( a ) arousal syndrome characterized by desynchronized electrical activities in the neocortex with synchronization in the hippocampus, caudate nucleus, thalamus and midbrain reticular system; ( b ) increased arousal reaction to sensory and reticular stimuli; ( c ) slightly increased cortical potentials evoked by stimulation of the reticular system; ( d ) markedly increased cortical potentials evoked by stimulation of the hippocampus and caudate nucleus; ( e ) decreased recruiting potentials evoked by stimulation of the medial thalamus; ( f ) unaltered or slightly decreased cortical potentials evoked by stimulation of the ventrolateral thalamus. Most of these effects were suppressed by atropine. These facts prove the existence of cholinoceptive substrates inhibiting synchronization in the neocortex and of other cholinoceptive substrates facilitating synchronization in the archicortex (hippocampus) and caudate nucleus. The action of GABA is very often similar to that of acetylcholine and other parasympathico-mimetic drugs.

L'électro-rétinogramme de l'homme

Abstract A method of perimetric electroretinography is described, by means of which the action of duration, intensity, colour and location of the light stimuli on the human ERG can be studied. The analysis of more than 1,800 records confirms that the human ERG belongs to Granits E type. Its most characteristic feature is the b potential, quantitatively defined by the latency, the duration of the ascendant phase or culmination time, and the amplitude, a and c potentials are small and often variable. There is no positive off-effect. Binocular electroretinography elicits, together with a normal ERG in the illuminated eye, a consensual response in the other eye, a reaction which seems to be coincident with the pupillary consensual reflex. The ability of the retina to differentiate light changes can be measured objectively by the fusion frequency of the small b potentials, elicited by flicker stimulation. The fusion occurs normally at a rate of more than 19–20, often of more than 26 flashes per sec. The ERG in man varies not only with the duration, but also with the intensity of the stimulus. Increase of intensity produces a decrease in the latency and culmination time of potential b, as well as an increase in its amplitude. Perimetric electroretinography permits the study of the reactivity of various retinal areas and the objective delimination of the visual field. In the normal subject, stimulation of peripheral areas (60° nasal retina) produces an ERG with longer latency and culmination time, and smaller amplitude of the b potential than those elicited by stimulation of more central areas. Stimulation of the retina with monochromatic light stimuli elicits: 1. A photopic component, particularly marked when the central area of the retina, adapted to light, is stimulated with red light, 2. A scotopic component, with slow and broad ‘b’ potential, particularly marked when the peripheral area of the retina, adapted to darkness, is stimulated with blue light. This scotopic response shows a longer culmination time when the wave-length of the stimulus decreases: it reaches its maximum when the peripheral retina is stimulated with blue light. Simultaneous recording of ERG and EEG permits measurement of the retino-cortical time, as well as of the alpha-blocking time. The retino-cortical time, that is, the latency of the evoked potentials, is more constant than the alpha-blocking time, being only 50 msec. (±15). Measurement of the retinal time, the retino-cortical time, and the alpha-blocking time can provide useful information about the functional state of the various sections of the visual tracts and centres.

Action de la Psilocybine sur le cerveau du lapin

Psilocybin, the by-product of which ‘Psilocin] has been identified as 4-hydroxy-dimethyl-tryptamine (4-HTP) develops in the waking rabbit a marked activation of the somatic behaviour and of the electrical brain activity. This stimulating action is due to a depression of the mediothalamic recruiting and moderating system rather than to an activation of the reticular arousal system. The electrophysiological effects of 4-HTP are compared with those of 5-HTP.

Les manifestations électriques consensuelles de l'activité rétinienne chez l'homme (Electrorétinographie binoculaire)

Binocular Electroretinography in man shows that the elective light-stimulation of one retina produces a normal Electroretinogramm at the stimulated, ipsilateral eye, furthermore a bioelectric consensual response at the contralateral eye. This latter response consists in a positive deflection, corresponding to increased electropositivity under the corneal electrode. A close synchronism exists between the consensual response and the secondary rise (c-potential) of the ipsilateral Electroretinogramm. The consensual response does not appear to be of pupillary or oculomotor origin, but can probably be identified with thec-potential, the significance of which will have to bee reexamined, as well as the problem of the efferent innervation of the retina.

Electroretinography with basal lead and without corneal electrode

Abstract A new method is described for electroretinography, consisting in the use of a naso-pharyngeal, basal electrode, and of an infraorbital or nasal electrode, instead of the irritating corneal electrode. The latency and culmination time of the b-potential of the ERGs obtained by this orbito-basal lead have the same values as those derived from a corneo-basal lead, but the amplitude appears to be smaller. The method is much simpler to apply for clinical purposes, chiefly in patients with strong reactions of the lids and eye-balls.

Biology of sleep. An interdisciplinary survey

Editorial remark. The following articles report, on a broad biological basis, on the real problem of sleep. We wish to thank especially M. Monnier, the well known collaborator of W. R. Hess, for preparing this interdisciplinary survey together with the other sleep specialists. We should mention that the problem of dreams (Morpheus) is beyond the scope of this survey on sleep (Hypnos) and will be the subject of a later article. H.M.

Hemmung subkortikal ausgelöster Krampfpotentiale durchβ-Hexachlorcyclohexan

Treatment of rabbits with a single dosis ofβ-Hexachlorcyclohexane prevents, for many days, the apparition in the electro-encephalogramm, of seizure potentials induced by electrical stimulation of an epileptogenic brain area, as well as the apparition of Metrazol seizure potentials. The results of the electrical test showed that theβ-component of the Hexachlorcyclohexane acts chiefly by changing the reactivity of definite diencephalic areas (Thalamus).

Topographischer Atlas des Hirnstammes der Katze und des Affen

In der Hirnforschung werden je nach dem Ziel der Arbeit Frontalschnitte, Horizontalschnitte, Sagittalschnitte oder sogar schrage Schnitte angewendet. Ein kurzer Ruckblick uber die neurologischen Veroffentlichungen der letzten 20 Jahre zeigt jedoch deutlich, das von den Embryologen (Herrick, Windle), Anatomen (Winkler und Potter, Tandler, Braun, Benninghoff, Ranson, Clara) und vergleichenden Anatomen (Papez, Kappers, Huber und Crosby) Frontalschnitte immer bevorzugt werden. Das Handbuch der Neurologie von Bumke und Foerster (1935) und die „Icones Neurologicae“ von Muller und Spatz (1926) reproduzieren ebenfalls vorwiegend Frontalschnitte des Gehirns. Spatz (1935) hat in Anlehnung an die Spielmeyersche Schule nicht nur den Vorteil der reinen Frontalschnitte hervorgehoben, sondern auch beschrieben, wie man diese technisch am besten herstellen kann. „Im Bereich der Mittelhirn-Zwischenhirn-Grenze erfahrt die Achse des Neuralrohres eine fast rechtwinklige Abbiegung. Die Achse des Mittelhirns entspricht noch der Achse des tieferen Hirnstammes und des Ruckenmarkes, der sog. Meynertschen Achse, welche beim aufrecht-stehenden Menschen von ‚unten nach oben‘ zieht; dagegen verlauft die Achse des anschliesenden Zwischenhirns (ebenso wie die des Endhirns), die Forelsche Achse von ‚hinten nach vorne‘. Zum Studium des Mittelhirns sind Schnitte zu bevorzugen, welche senkrecht zur Meynertschen Achse stehen.“

Physiologische Schwankungen des Netzhautarteriendruckes

Wir haben darauf hingewiesen, das der Netzhautarteriendruck normalerweise in einem konstanten Verhaltnis zum allgemeinen Druck steht, ob dieser hoch oder niedrig ist (vgl. S. 17).

Der Blutdruck in den Netzhautcapillaren

Man kann den Capillardruck dadurch bestimmen, das man von ausen her einen Druck auf das Gewebe (Haut, Schleimhaut): mittels einer Recklinghausen-Kapsel ausubt und den Wert notiert, bei welchem das Gewebe blas zu werden beginnt. Die Fehlerquellen eines solchen Verfahrens sind aber betrachtlich. Der nach dieser Methode gemessene Capillardruck ist niedrig und variiert nach den verschiedensten hamodynamischen Bedingungen. Er nimmt vor allem bei Erweiterung der Arteriolen zu und umgekehrt.