When a portion of retina is stimulated by light, the areas surrounding the stimulated part undergo a change in excitability. The author has studied this phenomenon under various conditions. In the present research, it has been investigated through the measurement of visual utilization time of a small light spot. The main results may be summarized as follows: 1) When the dark adapted eye with an artificial pupil is given a weak light stimulus, the regions near the stimulated point become excitable. This phenomenon had better be called “the first phase facilitation”. As time elapses, however, the amount of facilitation falls gradually to zero, and then, nhibition occurs. It increases by degrees and reaches its maximum at about the moment of the removal of light stimulus. After that, as time passes, gradual diminution of inhibition follows and then there is a return to the normal state. Then, unexpectedly, the normal state is immediately broken and slight facilitation appears again. This may be called “the second phase facilitation”. 2) The shifting course of “facilitation-inhibition facilitation” is the fundamental type of variation inretinal excitability, which is found in all the present experiments. The experimental variables, such as the exposure time of the inspection light stimulus, brightness of the stimulus, the spatial distance between the inspection figure and the test patch, and so on, do not change the above-mentioned standard shifting course. 3) Within a certain extent, the brighter the light stimulus is, the less the amount of facilitation and the greater the amount of inhibition becomes. Even if the exposure time of the inspection light stimulus is made longer, it can produce the same effect as the above-mentioned effect. 4) In retinal areas remote from the point of stimulation, the process of “facilitation-inhibition-facilitation” takes place, too. But both facilitation and inhibition are less in amount there than at the parts nearer to the point stimulated. These results are useful to set up a new hypothesis which will be able to account for Köhler-effect, tau-effect and many other phenomena of perception.
It is the purpose of these experiments to demonstrate the variation of the preference-aversion functions for NaCl and for KCl among the normal, the adrenalectomized and the convulsed rats subjected to the self-selection. Each solution was presented in a random order. The obtained data are in terms of the mean intake per 24hrs. of each concentration of solution. The intakes of solutions, tap water and food are expressed on a body weight basis (gm. or c.c./100gm. B.W./day/rat). The results of these experiments are thus as follows: (1) In the self-selection situation, the normal rats showed a typical preference-aversion function for NaCl and for KCl (Fig. 1). The preference threshold is about 0.05 per cent NaCl and about 0.04 per cent KCl solution. The optimal concentration is about 0.9 per cent NaCl and about 0.1 per cent KCl. The aversion threshold is around 1.5 per cent NaCl and 0.9 per cent KCl solution, where all the rats drank less of each solution than the tap water. (2) As can be seen in Fig. 2, the bilateral adrenalectomized rats showed an increase of the intake of NaCl after the rest-period of 16 days. Moreover, when given a chance to choose among water, 0.9 per cent NaCl and 0.1 per cent KCl solution, the adrenalectomized rats showed a greater increase in the intake of NaCl and also a greater decrease in that of KCl than the normal rats. As for the preference-aversion functions, the adrenalectomized rats showed a decrease in the preference threshold (0.02-0.03 per cent) and an increase in the intake of all concentrations of NaCl solution in comparison to the normal rats. (3) The convulsed rats treated daily with ten ECS administrations showed the preference-aversion functions similar to those of the normal ones, differing only in the amount of intakes, i.e., a decrease in NaCl and an increase in KCl for all concentrations employed (Fig. 3). (4) There is a significant difference in the level of the physiological need for Na and K between the normal and the adrenalectomized animals (cf. Table 2 and 3). On the other hand, it is interesting to note that the convulsed rats chose to take significantly less NaCl and more KCl solution in each situation than the normal and the adrenalectomized rats. Therefore, relative Na aversion and K preference by the convulsed animals might result from the functional hypertrophy of the adrenal cortex. This verifies the findings of Rosvold et al., although there is no histological examination of the adrenal gland in this experiment. (5) The convulsed as well as the adrenalectomized animals showed a decrement in body weight immediately after the treatment and a gradual recovery during the remainder of the experiment. The paralysis in the thoracic region downward appeared in the 33.5 per cent of the convulsed group. It may be concluded from these findings that the change of the preference-aversion functions under the conditions of the stress suggests some possible mechanisms by which endocrinological and metabolic responses act together to manifest a behavioral disturbance.
The purpose was to ascertain the characteristics of the P-and E-functions in the comparison of the temporal length given as the duration of tone (substantial time), where the former function represented the time-error as a function of the length of pause between tones, and the latter indicated that as a function of the length of time under comparison. The changes in the length either of pause (P) (Tables 1 and 2) or of duration (E) (Tables 3 and 4) revealed that both functions were similar in tendency, i.e., the time-error was negative and remarkable at the shorter Ps or Es, but the error gradually decreased its amount and approached zero as P or E became longer. Within a single series, however, the changes in both P and E (Table 5) yielded a disagreement with the preceding results in the amount of error. The disagreement was more remarkable and the individual differences were larger when each combination of P and E constructed a separate series (Table 6). These disagreements are possibly due to the difference in the manner of constructing the stimulus series. A continued experimentation on a single stimulus condition showed no specific transition of error (Table 8). On the other hand, the repetition of a series, which was constructed by various stimulus conditions, increased or decreased the amount of error in that series as a whole (Table 9). The effect of the distribution of variable stimuli was hardly observed within the range of the present experiment (Table 10). The linear representation of the relative proportion of E-P-E did not result in any specific tendency in P- or E-function. By introspective method the following impressions were reported: a rhythm in binary time (R), aggregation of Es into a single unit (A), segregation of Es into pieces (S), a phrasing composed of two bars in binary time (P), and a wave-like image of E or oppressive impression (W) (Table 11). And the reports changed from R, through A, A and P, to W according to the elongation of either P or E. Such a complementary relation between P and E was indicated by the modification of E-function in the order of the length of P, in another detailed experiment (Table 12). If the effects of series construction and repetition were eliminated, E-functions for respective Ps, and P-function for respective Es also, could be brought to coincidence with each other by transformation of coordinate system (Fig. 1). These experimental results suggest that P- and E-functions are divided into three phases. Phase 1: at shorter Ps or Es the amount of error varies largely, though being always negative. Phase 2: at moderate Ps or Es the negative error decreases as P or E gets length, and both functions appear in a similar form. Phase 3: at longer Ps or Es, P-function is horizontal, while E-function descends to the negative side as E increases. The first phase, corresponds to the impression R, the second to A, S and P, and the third to W. Many kinds of factors would be complicated under the phenomena of time-error. Therefore, further analysis of conditions affecting the phenomena would be required rather than the attempt at an integrated explanation.
In the first half of the article it was reported that we succeeded to confirm the discoveries made by Motokawa concerning with the electrical excitability of the eye, e.g., the indirect induction, its propagation and the neutralization. The experiments consisted in determining under various conditions the threshold for the phosphene which was evoked by a single constant pulse of 0.1sec. given through the silver electrodes attached to the brow and cheek. A kind of the method of limits in the descending series was employed and special caution was taken against the possibility that expectation of the experimenter or of the subject influences the result. The excitability of the eye, the reciprocal of the threshold, is enhanced if a flash of light is presented before the pulse is delivered and this enhancement is expressed by an index ζ. Then, the induction is an increase observed in ζ when the white light is preceeded by a colored light. The induction vanishes, however, if a flash of the complementary color intervenes between the two flashes, the colored and the white, and this is what is called the neutralization. The propagation of the induction is demonstrated by the fact that the neutralization is observed even when the complementary one is given to a part of the retina apart from the part where the colored one is presented. A series of the experiments were designed to make a thorough inquiry into the nature of the coordinate system according to which the propagation of the induction takes its path and a part of the results was described in the second part. Two alternative hypotheses were proposed as shown in Fig. 5, where R denotes the one that the propagation takes place in accordance with the pattern of the retinal stimulation and P the other that configuration of the induction comes to form in accordance with what the subject perceives under the given conditions. Then it was demonstrated that there existed the case where the P-hypothesis holds. For instance, under the condition that fixation shifts from the left mark to the right one between the presentation of the figures III and IV of Fig. 4, the induction initiated by Y was observed with the point 1 and the induction initiated by B arrived to the point 2 to neutralize the induction evoked by Y. These are exactly what are expected from the P-hypothesis because the point 1 is seen above the place where Y is perceived in I and the point 2 below the place where B is perceived in II. If III is omitted and the fixation shifts between II and IV, however, the induction propagates in terms of the R-hypothesis. The results were obtained with all of the three subjects.
According to N. E. Miller, fear is a learnable drive, and therefore, is defined as response-produced stimulus. Confronting danger situation, animal responds to it with the muscle tension and this tense response becomes stimulus in the organism which works as a drive or cue for further instrumental response. Ordinarily drive state is controled on a certain level (e.g. 23hrs. hunger drive), and cue is given a certain distinctiveness. There is established a univocal relationship between them. However the drive state has oscillation in itself. A response produces oscillation in a drive state and the varied drive state produces further instrumental responses. We postulate that the reinforcing value which the stimulus context carries, is reversible from rewarding to punishing, and vice versa, in accordance with the variability of the drive state that occurs with the lapse of time. Experiment I. In order to test the hypothesis of the reversibleness of reinforcing value in the stimulus context, three kinds of stimulus contexts, that is, buzzer-shock (black wall): buzzer-shock (white), buzzer-shock (black): shock (white), shock (black): shock (white) were used in a shuttle box. Number of avoidance responses is shown in Table 1. When animal runs to white side, the white side is rewarding, but this side becomes gradually punishing as time goes by, then he returns to the black side. Experiment II. In order to find the effect of the variability of the drive state which occurs with the lapse of time, animal was trained on avoidance in buzzer-shock: shock, or the unequal reinforcingstimulus context. The results are shown in the Tables 2, 3, 4. On the first day of training, animal stayed for 19.22min. out of 40.00min. on the black side, and on the last day of training, they stayed for 28.51min.. Animal may be said to prefer to stay more on the fear-reducing side than on the tense side. This is supported by the relative reinforcement theory of C. C. Perkins, Jr., though his theory does not necessarily require the drive concept. Experiment III. Fear works adaptably to any abrupt change of the stimulus context. After the completion of the avoidance training in buzzershock: shock stimuluss context, an extinction trial was introduced. The original black wall was suddenly replaced by an inserted white wall, and the original white by the inserted black one. The original and inserted stimuli were alternately presented for one min. each, and duration of stay on both sides was measured. As Fig. 1 shows, animal responds to the inserted black side with an adaptable avoidance. The curve for the duration of stay on the black side goes up until no difference is seen between the 9th inserted trial and the 10th original trial. In addition to this, a striped wall was used as an inserted wall. Almost the same result is shown in Fig. 2.