Masaichi Sawa

Intracellular phenomena in electrically induced seizures

Abstract Intracellular recordings were made from both pyramidal tract cells and non-pyramidal tract cells is the motor cortex of the cat. The responses elecited by single stimuli to the cortical surface or to the medullary pyramid were found to change during and after electrically induced seizures. Similar slow changes in the membrane potentials during and after seizures occurred in both types of cells but spikes superimposed on the smooth or oscillatory depolarization were more frequently observed in pyramidal tract elements. In these, antidromic spikes could be elicited during and after a seizure except when either marked depolarization occurred or when the stimulus fell in the refractory period. Responses characterized by a depolarizing wave (EPSP) could be generated by single stimuli during and after a seizure except towards the termination of the seizure. Responses characterized by a hyperpolarizing wave (IPSP) were never obtained by single shocks during and immediately after a seizure. The development, maintenance and termination of experimental epileptic seizure have been discussed on the basis of the above results.

Intracellular phenomena and spread of epileptic seizure discharges

Abstract The cellular behavior in the course of spreading seizure discharges has been investigated by means of intracellular recordings. These were obtained from cells in the left anterior sigmoid cortex of the cat during and after after-discharges induced by electrical stimulation of the surface of the ipsilateral posterior sigmoid cortex. The responses elicited by single stimuli to the cortical surface of either the anterior or the posterior sigmoid gyrus were also investigated before, during and after epileptiform activation. The intracellular potential changes observed were considered to reflect three different states of cell activity (propagated, projected and depressed seizure state). In a propagated seizure state , a sustained membrane depolarization was generated, in most instances, soon after the cessation of repetitive stimulation. Changes of synaptic potentials elicited by single stimuli were assumed to be similar to those of a cell that was directly induced into a seizure state following local tetanization applied to the cortex involving the cell. In a projected seizure state , little or no sustained depolarization occurred and polarizing waves were seen periodically with concurrent waves in the ECoG. Both excitatory post-synaptic potentials (EPSPs) and inhibitory post-synaptic potentials (IPSPs) could be generated by single stimuli during and after the seizure. In a depressed seizure state , no slow membrane oscillations nor spontaneous spikes could be observed at the resting level of the membrane. The EPSPs and IPSPs by single stimuli were depressed during the seizure, especially in its early stage. Some experimental evidence was obtained concerning a correlation between surface and intracellular potentials in these three seizure situations.

Preliminary report on the amygdaloidectomy on the psychotic patients, with interpretation of oral-emotional manifestation in schizophrenics.

The symptoms caused by the destruction of amygdaloid complex in man are: intensification of the anger impulse, changefulness and infantization of emotion and behavior, and increase of friendliness in the emotional aspect; polyphrasia, hyperkinesis, acceleration of psychomotor activity, phagomanic and heterophagous tendency, and want for water, and in two cases such abnormal oral behavior as spitting, and the arcentuation of the sexual impulse in behavioral aspect. In three cases erroneous recognition both of persons and objects nas observed. As these symptoms were entirely absent prior to the operation, being evidently independent from and unrelated to the schizophrenic symptoms, it may rightly be interpreted as the symptoms directly caused by the surgical attack on the amygdaloid complex. These symptoms, of course, varied according to the poatoperative course and circumstances, also never uniform in all the five cases. However, we shall outline below the course of the changes in symptoms for conveniences sake

REGULATORY INFLUENCE OF AMYGDALOID NUCLEI UPON THE UNITARY ACTIVITY IN VENTROMEDIAL NUCLEUS OF HYPOTHALAMUS

Under barbiturate anesthesia, the unitary activity of the ventromedial nucleus of the hypothalamus of 10 adult cats was picked up with the use of glass pipette electrodes, and the electrical stimulation on the three principal nuclei (lateral, medial and intermediate) of the amygdaloid nuclear complex was observed with reference to spike activities.

ACTIONS OF STIMULATION TO MEDULLARY PYRAMID ON SINGLE NEURONS IN CAT'S MOTOR CORTEX By

The electrical activities of single neurons in the anterior sigmoid gyrus of 45 adult cats were picked up intracellularly or extracellularly by means of microelectrode technique. The response patterns elicited by single shock applied to the medullary pyramid were recorded.

Epileptoid psychosis:a group of atypical endogenous psychoses.

Clinical and EEG studies were performed on 60 cases of a group of atypical endogenous psychoses. The onset of psychic symptoms was sudden after a short period of melancholia, displeasure and insomnia.

THE EFFECT OF CERTAIN RADIOACTIVE SUBSTANCES ON THE ELECTRICAL ACTIVITY OF RABBIT'S BRAIN

We made hitherto series of physiological or pathophysiological investigations on the central neivoiis system using radioactive incl. isotopic substances, with purpose of elucidating effect of those substances upon the animal brains. Previous to isotope, thoria(Th6J came into use before our equipment was completed and isotope was delivered. Using them ar.d paying special attention on the electroencephalographic pattern, we could obtain series of distinct findings, for instance, characteristic spikes as will be mentioned in the following paragraphs, about the nature of which there is no elucidation as yet. Here will be introduced these findings in detail.

A Study on Periodic Abnormal Discharge with Spike Components

Many reports on clinical cases showing periodic abnormal discharge (PAD) in electroencephalogram (EEG ) with periodic synchronous discharge (PSD) are available since Lesse (1956) presented the first cases. On the other hand, Hughes et al. (1965) reported PAD cases with periodically recurring focal discharge (PRFD) . However, no one seems to have performed comparative studies of these two types of PAD cases. We investigated 27 cases (male 15, femaIe 12) of PAD. As they were both of the PSD and PRFD types, we compared their clinical features giving particular attention to the EEG. We divided our cases into two groups based on the localization of spikes; one was the diffuse group, the other was the focal group. Twenty-two cases belonged to the diffuse

EFFECT OF ACETYLCHOLINE ON THE ELECTRICAL ACTIVITY OF THE BRAIN

There is no doubt in the extremely important rSle played by Acetylcholine (ACH j concerning the transmission of nerve impulses, i f there the basic argument be set aside for a while. It may be admitted, :it least, that the effort of Nachmansohn and his coworkers has brought chemical substance theory under a new light just in a rival seat against the action current theory. On the other hand, since Bomet and Bremer a considerable number of reports have been published on the effect of ACH in comparison with that of electrical activity of the brain, but arguments of the results being yet not unanimous. It seems a t present that the interest cowering action of ACH has been nroused from at least two viewpoints: namely, one concerning epileptic seizure discharges and the other treating the r6le played by ACH in the marked changes of electrical activity in case of brain trauma. We have attached presently the basic moments of these problems through the electrical phenomena as far as the circumstance allows.