1. The latency of photo-release of oxygen was about 3 minutes.
2. Photo-release of oxygen (μl) per dry weight of rhodopsin (mg) was represented by χ, which was augmented in the course of time of illumination.
3. A rise in experimental temperature θ resulted in an apparent increase of y and a gradual decrease of dy/dθ.
4. Relation between y and θis expressed as follows_??_and_??_
5. 2θ/10 indicates the effect of temperature on the photo-release of oxygen from rhodopsin.

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1. In the trigeminal motor nucleus, the motoneuron responded to light pressure applied to a restricted site of the masseter muscle.
2. The process of firing was differentiated into three phases. One was the phase with initial burst discharges at the onset of pressure application to the muscle, the second was the steady firing phase, and the third was the silent phase after removal of the pressure stimulus.
3. The activity of a motoneuron was depressed by light pressure applied about 20mm anterior from the focus in the muscle. It is reasonable to suppose that a motoneuron shows a prominent increase in discharge if pressure is applied to an area comparable to that of the spindle capsule, and that this motoneuron stops discharging by the slack of the muscle spindle when pressure is applied to some area distant from the site of the spindle capsule.
4. Time of recovery of motoneuron activity from both the excitation and the depression by pressure was completely proportional to the magnitude of applied pressure.
5. The area of the muscle which could fire a motoneuron by pressure was mainly located on the anterior site of the masseter muscle.

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Effects of Sch on responses of the trigeminal motoneuron induced by pressure applied to a restricted site on the masseter muscle were studied.
1. The optimal dose of Sch which effects the spontaneous discharges of the trigeminal motoneuron was about 0.8 mg/kg. The spontaneous discharge of the trigeminal motoneuron disappeared within 20 sec. after the injection of 0.8 mg/kg Sch and this silent phase continued for about 20 sec. After this stage the spontaneous discharge reappeared gradually and reached the maximum firing level at about 100 sec. after Sch in jection. At this stage the frequency of spontaneous firing was about 4 times greater than the control. This Sch effect continued for about 5min. However, a super optimal dose of Sch (1.2 mg/kg) induced grouped discharges of the motoneuron and the muscle showed local twitching.
2. The endplate of the extrafusal muscle fiber was more sensitive to Sch than that of the intrafusal muscle fiber.
3. It was confirmed that the pressure response of the trigeminal motoneuron originates from the deformation of the muscle spindle.

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Unit activities of the lateral geniculate body (LGB) were studied in free behaving cats during arousal, light sleep (sleep with high-voltage, slow EEG) and deep sleep (sleep with low-voltage, fast EEG). The LGB units were classified into two types according to their response patterns to stimulation of the optic chiasm and the visual cortex; by both types of stimulation the P units were fired singly at short latencies and the I units were fired repetitively at long latencies.
1. Spontaneous activity of the P units changed markedly upon alternation of the behavioral state. During arousal the P units showed well-spaced regular discharges. During light sleep the grouped discharges consisting of 2-5 spikes became manifest intermingled with sporadic discharges. In deep sleep spontaneous activity was accelarated with occasional bursts of spikes (deep sleep bursts) lasting about 0.5 sec.
2. The deep sleep waves of the LGB, which were mass activity of spiky form seen during deep sleep, were found to be correlated to the deep sleep burst of the P unit spontaneous activity in their negative phase. Suppression of the unit activity was seen during their positive phase.
3. The rate of spontaneous activity of the P units was lowest during light sleep and increased from arousal to deep sleep.
4. The firing probability of the P units to chiasmatic and visual cortical stimulation was lowest during light sleep and increased from arousal to deep sleep. This was true of the firing probability to the spontaneous synaptic bombardment.
5. The I units did not alter significantly the rate of spontaneous activity and the strength of responsiveness to visual cortical stimulation when sleep changed from one type to another. Responsiveness of the I units to chiasmatic stimulation was higher during deep sleep than during light sleep, suggesting that orthodromic activation of the I units is mediated via the P units.

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1. Single fusimotor units of the VIIth lumbar ventral root were recorded in the unanesthetized chronic cat. In the discharge patterns of the spontaneous activity in the sleep with slow wave and spindle in EEG (ortho-sleep) and in the response patterns of the units by arousing stimuli such as pinna pinching, two extreme patterns of the fusimotor units were described. The fusimotor unit, having one of these patterns, was termed as kinetic (K) or tonic (T), respectively. During ortho-sleep the kinetic unit fired unsteadily or was silent while the tonic one fired regularly. By awakening, the kinetic unit started to, fire or increased the rate dynamically, while the tonic unit increased the rate slightly.
2. During para-sleep, the spontaneous discharge decreased in rate in both kinetic and tonic units (tonic depression). There also occurred an appearance of the transient burst discharges, continuing for more than several sec in both tonic and kinetic units. The burst was more abrupt in the latter. In addition to the transient facilitation, there occurred a transient depression in the tonicunit. These transient facilitation and depression occassionally occurred during. rapid eye movement phase.

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1. The mechanism of the slow depressive potential (SDP) production has been investigated with the isolated frog retina deprived of the pigment epithelium.
2. Both the latency and the amplitude of the b-wave were affected by the evolution of the SDP. A decrease in amplitude and an increase in latency were observed during the development of the SDP.
3. Reduction of sodium or magnesium in the bathing solution did not affect significantly both the amplitude of the SDP and the b-wave latency.
4. Exposing the retina to the calcium-free solution, the amplitude of the SDP was decreased and the b-wave latency was lengthened gradually.
5. Lowering the potassium concentration on the receptor side caused an increase, on the contrary, raising the potassium concentration a decrease in amplitude of the SDP. There was a logarithmic relation between the amplitude of the SDP and potassium concentration in the bathing solution. Whereas, raising the potassium concentration on the receptor side led to an increase in the b-wave latency.
6. The ratio of E₁ and E₂ of the SDP remained constant even if various cation concentrations in the bathing solutions were modified.
7. The SDP induced by a light stimulus was interpreted as the summed response of the negative response and the positive response.
8. Observations from the present study suggested that the SDP is generated most probably by the Muller cell as a depolarization of a cell membrane except that forming the so-called inner limiting membrane.

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1) By utilizing the ultramicroelectrode technique combined with TRENNDELENBURG'S method the electrical activities were studied on isolated guineapig je junal loops.
2) With increase in the intraluminal pressure of the loops, the depolarization of the muscle cell membrane gradually increases, at first oscillating minutely, and being then summed up with each other to develop slow depolarizing waves having a more or less longer period.
3) When the summit of the depolarizing wave reaches a certain critical level, i. e., about 12 mV, there is initiated a spike, which is successively followed by an initial after-hyperpolarization (IAHP), the late after-depolarization (LADP) and a delayed after-hyperpolarization (DAHP), the last named one soon turning to the phase of an increasing depolarization, prepotential (PP), until it culminates in the induction of the spike again.
4) When the pressure is lowered, the spike is abolished and the slowwaves then decline in their amplitude, until they break into minute oscillations. The spike is thus responsible for fully developing the slow waves.
5) The late after-depolarization (LADP) is highly developed by applying acetylcholine or by raising the pressure to initiate repetitive spike potentials, . whereas they are reduced after the application of nicotine as well as of atropine or lowering the pressure.
6) In the isometric condition the slow waves can be completely abolished, . spikes being continually produced.
7) From the facts described in 1)-4) it may be said that the depolarizing waves ranging from minute oscillations to slow waves are essentially of the same nature. The facts described in 5) suggest that these waves are presumed to be elicited by acetylcholine released from the intramural nervous elements.

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1. Electroencephalographic studies were carried out on the developing 1-dayold to 4-month-old chick under unrestrained conditions. Electrodes were chronically implanted in the rostral and the caudal parts of the frontal bone
2. Fast waves of 17 to 25 cps and 30 to 60 cps with a low voltage of 25μV appeared during the opening of the eyes in the 1-day-old chick. Very slow waves of 1.5 to 5 cps with high amplitude were predominant during the drowsy or the sleeping state until 1-week of age. Until 1-month of age, high amplitude and slow waves of 6 to 12 cps appeared during drowsy or sleeping state. Twomonth- old birds showed adult characteristic in both behavior and the EEG patterns. Furthermore, during paradoxical sleep, high amplitude and slow waves were often interrupted with low voltage and fast waves similar to those of the wakened state. This episode was observed in 1-day-old chicks, and lasted for 2 to 11 seconds, mainly in the 3 to 4 second range. In addition, arousal EEG patterns associated with opening eyes were observed in the contralateral hemisphere of the forebrain in developing chicks from 1-day to 2-months of age.
3. The arousal response to auditory stimuli in the somnolent state existed in the 1-day-old chick, when the bird was awakened by sound. During the so-called “paradoxical” sleep, the low voltage and fast waves were shif ted to high amplitude and slow waves on the EEG by application of a mild or weak brief auditory stimulus, though no significant changes in sleeping behavior occurred.
4. In developing chicks, the hypnotic or cataleptic state was readily induced by abnormal enforced positions or the act of being hand-held. The younger the birds, the more readily they succumbed into the hypnotic state represented by high amplitude and slow waves which is characteristic of the drowsy or sleeping state.
5. Various types of seizure-like discharges were sometimes found under the drowsy or sleeping state in the developing chick, particularly in the newly hatched state. The persistence of those discharges varied, ranging from a little less than a minute to several minutes. These occurred locally or unilaterally in the rostral and the caudal parts of forebrain explored. The seizurelike discharges were induced also by intraperitoneal injection of large doses of Nembutal in newly hatched birds.

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1. Adult rats (Wistar King A) were used, thirty-seven animals for recording antidromic cortical responses, five for observation of the motor effect of cortical stimulation and three for histological sections of the cerebral cortex.
2. Electrical stimuli were applied to the medullary pyramidal tract in slightly anesthetized rats and the potential changes were recorded at the cortical surface and from various depths of the cortex.
3. The resultant responses of the cortex consisted of an initial sharp positive wave (P I) followed by a secondary small positive wave (P II) and a slow negative wave (N). The P I had the lowest threshold to medullary pyramid stimulation and most faithfully followed the increase in frequency of stimulation up to a frequency of 300/sec.
4. The distribution of the potential changes at various points of the cortical surface evoked with submaximal stimulation to the medullary pyramidal tract was measured. The maximal potential was recorded at a point 6.0 mm anterior from the line connecting the both ears and 3.0 mm lateral from the midline. The amplitude of the waves gradually decreased in the frontal direction from the maximal responsive point, and in the occipital direction it rapidly decreased to an immeasurably small level. The potential at the frontal pole was about one sixth of the maximum. In a lateral direction, the amplitude at a point 2.0 mm lateral from the midline was slightly small than at 3.0 mm and the amplitude both at 1.0 and 4.0 mm was about a half of that at 3.0 mm.
5. The distribution of the antidromic cortical response coincided fairly well with the histological distribution of the pyramidal cell in the cerebral cortex of the rat.
6. Recording from the depths of the cortex, the P I changed its polarity into a negative deflection at about 2.0 mm below the pial surface and the P II changed into a negative potential at a depth of about 1.5 mm. The N decreased to zero and sometimes seemed to reverse into a very small positive wave at about 1.5 mm below the surface.
7. The above results suggest that the P I corresponds to antidromic impulses which invaded the large pyramidal cells in the deeper cortical layers with axons of faster conduction velocity and that the P II is composed of the antidromic impulses of the pyramidal neurons in the more superficial layers with axons of slower conduction velocity. It is considered that the N might represent the potentials of the apical dendrites of pyramidal cells conducting toward. the pial surface.
8. The studies of cortical hemisphere stimulation reveal that the functional motor area occupies a part a little anterior to a location of the antidromic cortical response and the pyramidal cells.
9. The functional significance of the pyramidal tract in the rat was discussed.

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The relationships between the response configurations of evoked potentials and background EEG activities were investigated from the autocorrelogram and “response amplitude-frequency diagram” by using unanesthetized, immobilized rabbit.
Autocorrelograms of EEGs in the arousal state during repetitive flas h stimulation showed an increase of regularity and decrease of noise elements in the amplitudes of the evoked potentials. This elevated brain activity level means the increased acuity and clarity of sensory informations.
From the response amplitude-frequency diagram during repetitive lateral geniculate (GL) stimulation, the concentrating-accelerating tendency by arousal were evident in the activities of specific origin. That is to say, with change in the background EEG from sleep to arousal, every component of the cortical potentials evoked by GL stimulations of various frequencies were augmented and especially the responses to only one or two stimulating frequencies were found to show a concentrating increase. These frequencies correspond to the characteristic frequency in the specific system demonstrated in the previous paper (MIMURA et al., 1967). On the other hand, the responses to repetitive reticular (RF) stimulations of various low frequencies retained their irregularity in the response diagrams and, contrary to GL stimulation, their amplitudes were decreased due to arousal EEG. Peripherally induced responses to repetitive flash stimulation exhibited a very complicated behavior in their augmentative and depressive tendencies with change of background EEG, suggesting mixed or summated features due to both augmentative specific activities (by GL stimulation) and depressive non-specific activities (by RF stimulation).
The spontaneous regular EEG wave in arousal was discussed from the resemblance of frequencies in relation to the activity changes of the evoked potential.

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