The effect of adding a side pressure of isotonic character upon the carotid artery, a method originally reported by MIYAKAWA to create sustained oscillations in the mean arterial pressure level of rabbits, was reinvestigated with minor technical modifications in dogs. The expected oscillation was brought about successfully in all dogs. By recording the cerebral perfusion pressure (i. e. the pressure at the point distal to the side pressure loading site) and the cerebral blood flow simultaneously with the systemic arterial pressure, the roles of the Starling's resistance used to add side pressure were clearly demonstrated:(1) it operates as a sort of limiter for cerebral perfusion pressure or blood flow, and thus amplifies the changes of the cerebral arterial pressure in a nonlinear fashion 2 to 12 times as large as that in the systemic arterial pressure, and (2) it also biases the mean operating level of the effective cerebral arterial pressure toward zero from the ordinary systemic arterial pressure level. Both roles increase the over-all gain and time lag of the system response and render the system quite unstable. Thus, the present experiment reveals the feedback nature of arterial pressure oscillation elicited by adding the side pressure upon the cerebral arterial pressure.

View full abstract

Brief exponential shocks were delivered upon the fresh neurula developing from the ovum of a white leghorn incubated under optimum temperature of 38°C, and the responses were led off on the oscilloscope connecting with a RC coupled amplifier and a direct one, and the following results were obtained:
1. An unfertil vitelline membrane was used as a contrast. The local responses of maximum height of 500μV with 200-250msec. of duration were generally observed, and occasionally after-potentials followed them. Plotting the maximum sizes of responses and the intensities of stimuli, the elevations increased exponentially in accordance with the growing stimuli. As for the polarities, the positive and the negative slow local responses were observed, when the polarities of shocks were reversed.
2. Well developed primitive central nervous and circulatory systems were detected on the chick's neurula which was incubated under the suitable temperature for 40 hour, and with the changes in form of animal life, electric patterns of response were also transformed into very complicated shapes and many irregular impulses overlapped upon the after-potential.
3. The primitive type of electrocardiogram was recorded from the preparations of 50 hour incubation, and it was nearly approximated to the typical pattern as labeled P-QRS-T, but QRS showed a dome in place of a spike.
4. The response keeping all-or-none law was disclosed from the sample of 70 hour incubation, and the correlation between the latency and the stimulus draws hyperbola known as Weiss' formula, and the locus of this special pattern is deduced from the primitive cardiac muscle judging from the position of electrode.
5. Briefly, the new born tissues like the primitive nervous and circulatory systems appear one after another upon a chick's neurula in the progress of development, and the varieties of oscillograms accompanied with the transformation of animal life were all clearly observed at the end of the local elevation.

View full abstract

The effects of rhythmic or random photic and sonic stimulations upon the called minor tremors (MT) on the human body surface were studied. MT was traced by an electroencephalograph simultaneously with the recording of electroencephalogram (EEG) and heart beat or electrocardiogram (EKG). In addition to simple visual inspection of the tracings, the average time-and frequency-patterns were obtained for some cases by auto-and crosscorrelogram and power spectra analysis respectively.
The study of the MT tracing and crosscorrelogram between the stimulation and MT showed that MT components which synchronize with the frequency of the stimulation were driven by rhythmic flash stimulation. In addition, increased regularity and rhythmicity of MT were found in the autocorrelogram of MT, even when the driven component of MT produced by stimulation is not so evident on visual inspection. On the other hand, it was shown in the autocorrelogram that the damping of oscillation becomes faster by random flash stimulation. The same phenomena as those produced by photic stimulation were also demonstrated with rhythmic and random sonic stimulations, though is not so clear as those in rhythmic and random flash stimulations.
From the above results, it seems likely that the central process of the neuromuscular system such as augmentation and inhibition might be represented respectively by the increase and decrease of driven MT during various sensory stimulations, though ballistcardiographic oscillations are mixed in MT.

View full abstract

1. Bilateral ablation of cortical acoustic areas or sub-areas was performed on the dogs and functional roles of these areas were investigated by salivary conditioned reflex method.
2. On the other hand, the levels of the central nervous system required to establish and to preserve the acoustic conditioned reflexes were examined.
3. In all cases, the positive conditioned reflexes as excitatory processes were essentially unimpaired.
4. On the contrary, the differential inhibition was affected. The disturbance in its postoperative formation was more marked than impairment due to cortical destruction of pre-established differential inhibition, though no essential difference was found between them. In the case of the successive removal of the acoustic sub-areas, the differential inhibition was most affected after the bilateral ablation of posterior ectosylvian gyrus which is generally regarded as a secondary acoustic area.
5. From these results, it is suggested that the excitatory process in the acoustic conditioned reflexes can be compensated by remaining cortical areas or subcortical centers, but in respect to satisfactory fulfilment of the inhibitory process especially of the differential inhibition, the presence of the acoustic area is indispensable.

View full abstract

1. By recording the integrated response of the glossopharyngeal nerve, the relative stimulating effectiveness of cations and anions on the frog tongue was measured.
2. Cations show stronger stimulating strength as compared with anions. The order of effectiveness is NH₄>K>Cs>Na>Li for monovalent cations of 1/2 M and Ca>Sr>Mg>Ba for divalent cations of 1/64 M.
3. In the anion series no remarkable difference in the response magnitude was observed. Saccharin soluble, which is the monovalent organic sodium salt, shows nearly equal stimulating effectiveness to the monovalent inorganic sodium salts, while sodium glutamate gives smaller value.

View full abstract

1. Effects of stimulation of cerebellar and thalamic nuclei on the spinal function were tested by recording monosynaptic reflex discharges from ventral roots and recording intracellular potentials from alpha motoneurons in the lumbar segments of the cat.
2. The effect elicited by single pulse stimulation of nuclei was fairly the same between the animals under very light anesthesia and good general conditions. However, it was easily variable with a slight change of the animal conditions.
3. Single stimulation of the fastigial nucleus (FN) elicited two group facilitations upon the monosynaptic reflex set up by tibial nerve stimulation (extensor), the one at a latency of about 10msec with a relatively short lapse and the other at a latency of 20-30msec with a long-lasting slow time course of 50-100msec. The facilitations appeared on bilateral bodily sides but more marked on the ipsilateral side than the contralateral. Scarce effect was observed with the FN stimulation upon the reflex set up by peroneal nerve stimulation (flexor).
4. Single stimulation of the interpositus nucleus (IN) produced the reciprocal effect that was facilitatory upon the ipsilateral flexor reflex at a latency of 10-15msec while inhibitory upon the ipsilateral extensor reflex at a latency of about 15msec. Somewhat similar but undistinguishable effect was elicited upon the contralateral side.
5. The effect of stimulating the dentate nucleus (DN) was characterized by the long-lasting slow facilitation upon bilateral peroneal and tibial reflexes. The facilitation appeared usually at a latency of 50-100msec and continued for about 100msec or more. It was often preceded by the other facilitation of a short latency of 10-15msec and of a relatively short duration.
6. Single stimulation of the ventral-lateral nucleus of the thalamus (VL) elicited the facilitation upon bilateral peroneal and tibial reflexes at a latency of about 15 msec although far dominant upon the contralateral side. The time course of the facilitation showed an initial steep increase and a following slow decay. The lapse of the decay was always longer in the extensor reflex than the flexor one.
7. Effects of repetitive stimulation of a nucleus were, in usual, deducible from the effect of single pulse stimulation of that nucleus as its temporal summation. However, they were rather complicated when compared with the single stimulation.
8. The facilitation and inhibition of the monosynaptic reflex by stimulating cerebellar and thalamic nuclei seemed, in almost all cases, to be elicited by PSP mechanism in motoneurons which was produced directly or indirectly with descending impulses through spinal tracts.
9. DN stimulation set up the inhibitory effect upon some motoneurons without any remarkable membrane potential change. Analyses of the effect showed, however, that the inhibition may be due to the shunting effect of the motoneuronal membrane by both EPSP's and IPSP's which converged to the motoneuron with a balancing amount and were neutralized mutually at the resting potential level.
10. Most of PSP's in motoneurons elicited by the cerebellar and thalamic stimulation, especially the late group PSP's, were consisted of both EPSP's and IPSP's. Facilitation or inhibition of the motoneurons by the stimulation was the net result of the both PSP's.

View full abstract

As a part of studies on the physiological mechanism for the establishment and maintenance of diurnal body temperature rhythm, observation to reveal possible factors affecting the development of temperature pattern was made with particular reference to observations during voyage and the length of daily routine.
1. The time of morning rise in body temperature coincided best with the respective local time, and less with the respective longitude, the time of sunrise or sunset.
2. During severe vertigo due to seasickness, the temperature rise in the daytime was suppressed remarkably, but the morning rise hardly disappeared under any circumstances.
3. High ambient temperature during the voyage exerted no influence on the level of temperature plateau in the daytime, but it delayed the night fall.
4. Any change in the diurnal fluctuation was not observed in the temperature curve taken in a cell 320m under the ground.
5. Based on observation of daily pattern of body temperature during prolonged or inverted daily routine, irregular shift of daily routine for years and during vertigo caused by medicine, it is highly reasonable to assume that the mechanism is primarily attributable to the inner rhythm of functional pattern which has been acquired mainly through vestibular functions. Besides, it may be presumed that there exists a certain limit to the non-twenty-four-hour schedule of living to which the body temperature rhythm can adjust itself.

View full abstract

By means of an improved type of suction electrode with a fine tip, the characteristic action potential (A-V potential) was recorded from the A-V groove of the heart of toad. The features of A-V potential as distinct from those of the atrium and ventricle were as follows: the rising velocity of upstroke was low, its amplitude was small (5mV on the average as contrasted to 40mV in the atrial or ventricular action potential) and the peak of spike was rounded. The A-V groove was not everywhere conductile, but the conduction was confined in two, well circumscribed areas (about 1mm×1mm in size) at the dorsal and ventral parts of the A-V groove. They were behind the A-V valve and in close proximity to Bidder's ganglia. In the majority of cases, the dorsal pathway played a dominant role in the A-V conduction. When this pathway was artificially suppressed by some procedures, such as a septal nerve stimulation and topical application of acetylcholine, the ventral pathway took over the role of A-V conduction.
By stepwise shifting of the exploring suction electrode carefully from the atrium to the ventricle, it was possible to trace the temporal sequence of excitation along the A-V pathway. The propagation of excitation in the pathway was found to be uniform and the conduction velocity was surprisingly low (ca. 2mm/sec at 15°C). The normal A-V delay is thus due to an extremely slow but uniform conduction in the A-V conducting pathway. In antidromic conduction, the V-A conduction was also found to be uniform but its velocity was usually lower than in orthodromic conduction. The uniform conduction through the pathway was well maintained even when the A-V interval was markedly prolonged at low temperature.
Increase in driving rate, however, changed the uniform conduction in the pathway into a decremental conduction. This is considered to be due to a slow recovery of excitability (long refractoriness) of fibers in the A-V pathway.

View full abstract