1. Extra-and intra-cellular recordings of action potentials and miniature electrical oscillation (MEO) in the tymbal muscle and the recording of vocal vibration were performed with the tymbal nerve-tymbal muscle preparation of some cicadae.
2. MEO had a characteristic interval (T) which was specific in respective species and was liable to synchronize with interval near about T or its integral multiples.
3. Repetitive action potentials caused by single shock related closely with MEO and the intervals corresponded to T, 2T, …
4. The intervals of spontaneously discharged action potentials in a preparation innervated by mesothoracic ganglion also corresponded to T, 2T, … of MEO.
5. The repetition of vocal vibration was related to the action potential in ratio of 1: 1, so that the intervals of the former also corresponded to T, 2T, …
6. The muscle showed best responsibility for the stimulation in the frequency of 1/T, 1/2T, …
7. Therefore, it was recognized that the muscle was governed not only with nervous innervation but also with its characteristic interval (T) which was determined by the synchronization of MEO.

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1. Synaptic activities in the rostral segments (II, III and IV) of toad's spinal cord in situ were investigated by recording intracellular potentials of motoneurons.
2. In response to an afferent volley in the ipsilateral nerve branch to triceps or biceps muscle there appeared in some motoneurons a monosynaptic EPSP, from which a spike discharge occurred in some instances, without any superposition of delayed PSP's. Some other motoneurons responded with a typical IPSP, while the rest with EPSP's or insignificant undulatory changes of membrane potential, all starting at longer latencies than the monosynaptic delay.
3. Measured from the arrival of afferent volleys at the surface of the cord, the latencies of the monosynaptic EPSP's and the earliest IPSP's were 1.54±0.042 msec. and 3.06±0.113 msec. respectively (22-24°C). The latter is reasonably regarded to involve an extra synaptic delay.
4. EPSP and IPSP were nearly equal in their time course. The rise time and the time constant of decay of EPSP are 2.10±0.026 msec. and 8.0±0.6 msec., respectively, and those of IPSP are 2.15±0.211 msec. and 8.0±0.97 msec.(22-24°C).
5. Observations were also made on the equilibrium potential of IPSP which was found to be 10 to 20mV more hyperpolarized than the normal resting potential.

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1. Oxytocin in daily doses of 0.4 and 2.0 I. U. was injected intraperitoneally for 8 to 14 days into mature virgin rats. Their estrous cycle was not influenced at all by this treatment.
2. Oxytocin in a dose of 2.0 I. U. was injected singly at the stage of proestrus or estrus, or repeatedly starting at the stage of proestrus or estrus for 8 days. During the course of oxytocin treatment, silk threads were placed in the uterine horns of the animals. The injured parts of the uteri occasionally showed slight swelling, which could be regarded as a simple reaction to foreign substances. Deciduoma formation was not observed histologically.
3. In histological sections no differences could be noticed between the ovaries and mammary glands of oxytocin-treated rats and those of saline injected controls. Normal cyclic changes of the uteri were observed in the oxytocin injected rats as well as in the controls.
From these results it was inferred that oxytocin may have no effect in stimulating the release of prolactin from the anterior pituitary gland, at least in mature virgin rats.

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1. In anesthetized or decerebrate cats and dogs the effect of stimulation of the carotid sinus upon the activity of the long ciliary nerve was investigated by means of action potential study.
2. Electrical stimulation of the central end of the severed sinus nerve caused dual effects, inhibitory and facilitatory, in the impulse activity of the long ciliary nerve. However, raising the pressure in the carotid sinus, isolated and perfused, evoked only diminution or abolition of the ocular sympathetic activity, and such an inhibitory effect was abolished by cutting the sinus nerve.
3. From these results, it is concluded that the afferent impulses from the carotid sinus baroreceptors reflexly inhibit the impulse discharge from the ocular sympathetic centers.

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1. In a series of intercollicular decerebrated and decerebellated cats, the dorsal part of the lower medulla was explored in search for the modality and topographical arrangement of the spinal afferents, employing microelectrodes inserted freehand. All the responses were produced by mechanical deformation of peripheral tissues and were obtained ipsilaterally.
2. The responses observed were classified into three groups:(a) unit discharges responding to stimulation of deep tissues, showing slow adaptation (proprioceptive afferent)(b) unit discharges to movement of hairs or light touch on the skin, showing quick adaptation (tactile afferents) and (c) unit discharges driven by pressure upon the skin, showing slow adaptation (pressure afferents).
3. The tactile afferents were most frequently encountered in the gracile nucleus, while the proprioceptive afferents from deep structures were the commonest pattern in the cuneate nucleus. In the restiform body, the responses to hind limb stimulation were the commonest patter. n For any part of the body, the proprioceptive, pressure and tactile afferents were found in the decreasing order of occurrence. The paraalar area resembled the rstiform body in the modalities of the afferents projecting thereto. The major component of the fibers terminating in the paraalar area were from the hind limb via the dorsolateral funiculus. The proprioceptive afferents were the commonest pattern, but occurrence of the pressure afferents was relatively high.

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1. The actions of various sensory stimulation upon the induced wave of the olfactory bulb of a frog were studied.
2. The induced waves were inhibited by the application of pain and warmth on the skin, light to the eye and sound to the ear. They were also inhibited by the application of sodium chloride, cane sugar, acetic acid and quinine solution onto the tongue.
3. On the contrary, the induced waves were generally augmented by the application of touch and cold on the skin as well as distilled water on the tongue.
4. These findings support the view that there are facilitatory and inhibitory fibers in the centrifugal nervous system from the higher brain centers to the olfactory bulb. The biological functions of these two fiber systems were considered.

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1. In the dog, a segment of colon corresponding to the recto-sigmoid region of man, was kept in a temporary state of anemia by perfusing the blood vessels of the loop with TYRODE solution for 4 hours, blood circulation of the loop being resumed thereafter.
2. Periodic roentgenologic examinations between 14 and 350 days after operation, revealed that the perfused loop remained persistently in a state of constriction with marked or with slight dilatation of the colon proximal to that site. We feel, that the picture of congenital megacolon may thus be produced experimentally.
3. The intramural ganglion cells in the constricted loop had degenerated completely.

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The effect of single shock stimulation of the mesencephalic reticular formation upon the geniculate evoked potential and the response probability of optic radiation units to optic tract stimulation was studied in locally anesthetized and curarized cats.
1. The geniculate evoked potential following optic tract stimulation consisted of two components, i. e. the pre-and postsynaptic components respectively. By conditioning stimulation of the mesencephalic reticular formation the postsynaptic component alone was augmented for a few hundred msec. without significant alteration of the presynaptic one.
2. Remarkable facilitatory effects were obtainable only when a certain limited region of the mesencephalon was stimulated.
3. Discharges of single radiation units were explored, and it was found that they received facilitatory and/or inhibitory effects following reticular stimulation, the facilitatory effect being predominant in most units. These effects were manifested as changes in responsiveness of radiation units to liminal optic tract stimuli after conditioning reticular stimulation.
4. From the result mentioned above it was concluded that transmission at most geniculate synapses was facilitated following reticular stimulation.

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1. Fibrillation was induced through the administration of aconitine on the right atrium isolated from a young rabbit, and the electrical activity was recorded simultaneously from two fibers of the fibrillating atrial muscle.
2. Synchronism in activities of two fibers in the fibrillating atrium decreased with increase in electrode distance. The decrease was evident in the transverse direction far more than in the longitudinal direction.
3. Two types of slow or small depolarizations in the fibrillating atrial muscle was discriminated. One was the oscillating slow potential in the ectopic pacemaker and the other was the “junctional potential” produced probably by the electrotonic spread of the action potential of the contiguous fiber through the intercellular junction.
4. Discussions were made on the behavior of the fibrillating atrial muscle, obtaining a conclusion that the fibrillation will be regulated by the degree of decrement of the safety factor in the intercellular junctional portions.

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The information sent from the tympanic neuron of noctuid moths, Adris tyranus, Lagoptera juno, and Oraesia excavata, were studied electrophysiologically.
1. The tympanic organ of noctuid moths can send the phasic and tonic information through two tympanic neurons, fast and slowly adapting neurons. The threshold of the former is higher by 20-30dB than that of the latter.
2. The slowly adapting neuron responds to the sound of 1-85kc./sec. in A. tyranus and L. juno and of 1-45kc./sec. in O. excavata. The fast adapting neuron responds to the sound of 3 or 4-30kc./sec. in the former two species and of 3-25kc./sec. in the latter. The most effective frequencies to those neurons are between 10 and 20kc./sec.
3. The response area of the fast adapting neuron is relatively smaller than that of the slowly adapting one and the most effective frequency is the same in both neurons. The discharge patterns of those neurons bear no reference to the frequency of a sound. Therefore the tympanic neurons can not send the information about the frequency.
4. The number of impulses in two neurons changes with the change of sound intensity at the same proportion. With weak sound the slowly adapting neuron can well signal the change of sound intensity. In case of strong sound, the fast adapting neuron discharges too and supplements the information about the sound intensity.
5. The response of the slowly adapting neuron to a short tone burst regularly delivered is first masked by that to a continuous pure tone, but it becomes recognizable in two hysteretic manners, i. e. in one of them, the response to the tone burst becomes clear gradually by suppressing a train of impulses in the response to the continuous pure tone. In the other case, the response appears by augmenting impulse discharges in the response to the continuous pure tone. Such hysteretic responses are evoked on one and the same neuron by the different relation in intensity and frequency between two sounds.
6. The hysteretic responses are only observed when a tone burst with a short duration is delivered with a continuous pure tone. The mechanism is now unknown, but the hysteretic responses seems to show that the tympanic organ is convenient for detecting pulsatory sounds in a background noise.
7. Two neurons in the tympanic organ are very similar to the fast and slow cells in a crayfish stretch receptor. Those organs with fast and slowly adapting neurons may be a prototype of mechanoreceptors.

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Histological as well as electrophysiological studies on the auditory nerve of monkey revealed that
1. The cochlear nerve bundle is almost free from nerve cells whereas the vestibular nerve has many nerve cells in it.
2. The latency of response on each cochlear nerve fiber in response to sound stimulation was determined by measuring the time interval between the arrival of sound at the ear and the beginning of nerve fiber discharge recorded at the intracranial cochlear nerve bundle. It was very short, between 1.0 and 2.0 msec. when the CF of the neuron was higher than 100°cps. while it was rather long, longer than 2 msec. when the CF of the neuron was lower than 1000cps.
3. There was no discrepancy between the conclusion obtained from the electrophysiological studies on the cochlear nerve fibers and that obtained by the histological studies on the cochlear nerve.

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