In an earlier report (3), the authors have provided experimental evidence that, under certain circumstances, the configuration of the induction takes its form in accordance with what a subject perceives in the visual field. If the pre-illuminating patterns I, II, III and a point in IV of Fig. 1 are presented in succession and fixation is shifted from the left mark to the right one between the presentation of III and that of IV, the indirect induction of Y (yellow) in I is observed at the points 1 and 4 etc. in IV and the neutralization, i.e., the arrival of the induction initiated by B (blue) in II is demonstrated at the point 2 (the pattern P in Fig. 2). Let us consider the moment when IV is presented. The region of the retina that is pre-illuminated by I, II and III, if projected to the plane where the pre-illuminating patterns are presented, is given by the dotted figure in Fig. 2, whereas the full lined figure indicates the place where I, II and III are presented, i.e., where these patterns are perceived in the visual field. Hence, the only possible interpretation may be as follows. In so far as I, II, III and IV are presented, the configuration of the induction does not exist around the pre-illuminated region of the retina, but it does take its form around the region in the visual field where the pre-illuminating patterns are perceived. This is what we named the P-result and the discovery was so unexpected that the need of its confirmation from every possible angle was pressing. In a series of experiments described in this article, the pre-illuminating patterns, the shift of fixation, the delivery of the electrical pulse to the eye, the definition of the induction (contrast effect, CE) etc. were exactly the same as those employed in the previous experiments (3). However, the psychophysical method to obtain the electrical threshold for evoking the phosphene was changed. Namely, in place of the method of limits in the descending series, the one in the ascending series was employed in Experiment 3 (Fig. 3), and the constant method in Experiment 4 (Fig. 6). And it became clear, irrespective of the method, the P-result was always obtained under the conditions mentioned above. In passing, the goodness of fit of the φ(γ) function to the data in the case of the constant method was satisfactory as shown in Fig. 4 and in Fig. 5. So far, the interval of time between the cessation of IV and the delivery of the electrical pulse was fixed at 1.5sec. since only existence or non-existence of the induction of Y was at issue. In Experiment 5, however, the interval was changed from 1 to 3sec. for the purpose of obtaining the so-called ζ-time curve. The P-result was also ascertained because two distinctively different types of curves appeared as shown in Fig. 7. The one (at the points 1 and 4) is of typical type for existence of the induction and the other (at the point 2) for occurrence of the neutralization.
Pressure and touch are often described as the same kind of sensation because they are elicited by similar mechanical stimulation. But they are quite different subjectively as well as electro-physiologically. The author discriminated between them by the difference of subjective sensation, and studied the effects of additional side-pressure applied to relatively broad surface of the body upon pressure sensation. The sensitivity of pressure sensation was measured by the number of pressure spots within a given area of the skin. In normal resting subjects, the localization of pressure spots changes from one examination to another (Fig. 1), but the number is always nearly constant (Table 1). The author studied how side-pressure by a weight given to various parts of the body surface influenced upon the pressure sensitivity in the dorsal side of right forearm, and obtained the following results: 1) Side-pressure caused the decrease of pressure sensitivity in general. 2) The nearer was the location of side-pressure to the test area, the greater was it's decreasing effect (Table 2). 3) However, the decreasing effect of side-pressure applied to the dorsal side of right hand (distal from the test area) was less than that to the dorsal side of right forearm (proximal from the test area), even if both distances from the test area were nearly equal. This difference of the effect may be explained by the dermatome: the skin of the hand was innervated by the spinal nerve differing from that of the test area, whereas the forearm was innervated by the same nerve. But there is a problem on such simplified explanation. 4) The effect increased as the size and intensity of side-pressure increased. Side-pressure given on the forearm by a cuff also depressed the pressure sensitivity. In this procedure, the asphyxia took place and the sensation subjectively differed from the former case. So, in the latter case another mechanism might be considered. 5) The effect of side-pressure showed the maximum value within 1min. after pressure application (Fig. 2), regardless of intensity and location of applied pressure. Consequently, it may not be considered that the effect of side-pressure spreads around from the pressed area. 6) The after-effect was recognized and it disappeared within 1min. (Fig. 3). The obtained results can not be simply explained by the pressure block of the peripheral nerve trunks. The sensitivity of pressure sensation is depressed also by the other stimulation of the central nervous system, especially the effects of stimuli, depressing the clarity of consciousness, are very similar to side-pressure's. It may be followed that side-pressure on the skin causes the inhibitory effect on the central nervous system including the cerebral cortex. It is concluded that the depression of pressure sensitivity is not of peripheral origin, such as pressure nerve block, but results from the induction in a level or levels of the central nervous system.
Purpose and experimental procedure The purpose of the present study was to see how well the stochastic model for free recall verbal learning, devised by Bush-Mosteller and Miller-McGill, fits to data obtained by group experiments. Twenty-five items of meaningful or nonsense syllables were presented to subjects twenty-five times in randam order. On every trial, subject were required to recall them as many as possible in 70sec. Analysis of results: 1 Using Bush and Mosteller's avoidance model (cf. their book: chap. 11) the recall parameter (α1) and non recall parameter (α2) of specific syllables (data from 20 Ss.) were estimated (Fig. 1). The significance of these values is as follows; in case of meaningful syllables, not only on recall trials, but also on non-recall trials, there occured some“conditioning”or memorization, but in case of nonsense syllables, only the recall trial had the significant effect. The empirical values were put into the theoretical equation (1, 9) of recall scores, and statman data were computed (Fig. 3). The results show in general a rather good fit, but in some of the nonsense syllables fitting was not very good. A tentative explanation might be as follows; although in estimating the recall parameter, subjects were considered to attain perfect learning, they in fact did not reach the perfect level in 25 trials. Analysis of results: 2 Following Miller-McGill's two-parameter case, the initial recall probability (p0) and the recall parameter (α1) for 10 subjects were estimated (nonrecall parameter (α2) was proved to be identity for all Ss.) (Fig. 4). Putting these values into the theoretical equation for recall scores (2, 11) and probabilities of recalling just k times up to the n th trial P(Ak, n) (2, 3) the former fits pretty well as in the case of the stat-data (Fig. 5), but the latter does not fit so well (Fig. 6). Lastly, transitional probability (τk) i.e. probability of recalling on the next trial when previous recall had taken place k times, was computed from the data (Fig. 7). Two types of subjects can be categorized, of which the one showes continuous or gradual change of τk and the other showes rather non-continuous change or a qualitative gap. Using Spearmann's rank correlation between recall order on successive trials, it was found that in the former type (Fig. 9) items were recalled nearly in random order, while in the latter type items were framed in a certain order (not necessarily a meaningful one), which may be called“spontaneous liaison”(Fig. 8) on the part of subjects. Stochastic models for verbal learning were fairly good for the former type, but not necessarily so for the latter type. In this experiment, learning was stopped before subjects attained perfect level, chiefly because of time limit to administer the experiment. If we reduce the amount of material, arrange the similarity between items, or lengthen the memorization trials, will the goodness of fit be improved? For the answer we must wait for further research.
The present experiment was undertaken to find the effect of electroconvulsive shock (E. C. S.) on spontaneous alternation in the rat. After exploration and pretraining, 29 naive albino rats were given 11 successive free choice trials per day for 5 days in a T-maze with rewards on both sides. On the basis of percent alternation in this“pre-E. C. S.”period, rats were divided into the experimental group (19 rats) and the control group (10 rats). For the experimental group, E. C. S. was administered at the rate of one per day for 15 days. The measurement of alternation was continued in this“E. C. S. period”with the same procedure as in the“pre-E. C. S. period”. Intervals between the treatments of E. C. S. and the following tests of alternation were approximately 22 hours. The control group received the same numbers of pseudo-E. C. S. treatment instead of true E. C. S. treatment. Results 1) The first treatment of E. C. S. produced a significant decrement in percent alternation (Fig. 1). The most decrement was found after the 4th treatment of E. C. S. Although percent alternation of the experimental group thereafter showed a tendency to recover as the treatment progressed, there was a significant difference between two groups even after the 15th E. C. S. 2) Three kinds of measurement were used to examine the relationship between the strength of position preference and the effect of E. C. S. (a) Percent alternation with the inter-trial interval of 24 hours was increased by E. C. S. (Table 1). (b) The mean number of turns to the side which each rat chose in more than half of the total 220 trials was decreased in the early stage of the “E. C. S. period” (Fig. 2). These results of (a) and (b) would indicate that the position preferences found in the“pre-E. C. S. period”might temporarily be destroyed by the treatment of E. C. S. (c) However, the mean numbers of turns to the preferred side based on the daily trials were significantly increased by E. C. S. (Fig. 3). Moreover these scores corresponded reversely to percent alternation, that is, the more the animal showed the daily position preference, the lower was the percent alternation. 3) E. C. S. increased the running time, especially of the 1st daily run. This, however, would not explain the decrement of alternation, because on the 1st day of the“E. C. S. period”no significant difference was found in the running time between two groups. 4) Several signs of emotional behavior were found in the E. C. S. group. From these results and many other results on behavior variability which concerned with cerebral function, emotion etc., it was assumed that both the functional decrement of the cerebral cortex and the excessive excitment of the lower centers of emotion would produce the decrement of behavior variavility. Electroconvulsive shock may be one of the causes which produce this kind of decrement.