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Notes: 1,4-dithioketo-3,6-diphenyl-pyrrolo-[3,4-c]-pyrrole, which is a good charge generation material for a near-infrared electrophotographic photoreceptor, has three polymorphs called the I, II, and III forms. The I and II forms are transformed into the III form after having been kept in suitable organic solvents. On the other hand, the III form is changed to the I and/or II forms by heat treatment above 320 °C. Among the three polymorphs, only the highly ordered III form shows the necessary and characteristic absorption in the near-infrared region.

Notes: Responses of plasma vasoactive intestinal polypeptide (VIP) to methacholine inhalation and to exercise loading were studied in asthmatic patients to clarity a significant role of the peptidc. The mean of basal VIP in asthmatics was not significantly different from the normals. The levels were increased after FEV (1. 0) (forced expiratory volume in a second) decreased to 80% of the baseline following methacholine inhalation and were returned to values similar to the baseline when FEV (1. 0) recovered to 100%. Thirty minutes after the exercise, mean VIP was significantly lower in patients with the lowest FEV (1. 0). These results suggest that VIPergic system contributes, at least partly, to relax constricted bronchioles in some patients with bronchial asthma.

Notes: Abstract A naturally occurring member of ubiquinone (Q) group, a dihydroubiquinone-9 (Q-9 (H2)), has been isolated as a minor ubiquinone component from the fungus Aureobasidium pullulans. By ultraviolet absorption, mass and nuclear magnetic resonance spectrometric studies, the structure of Q-9 (H2) was found to be 2,3-dimethoxy-5-methyl-6-IX-dihydromultiprenyl9-1,4-benzoquinone (I).

Notes: Summary The formation of lignin in the cell wall of compression wood of Pinus thunbergii was examined by selective radio-labeling of specific structural units in the lignin and visualization of the label in the different morphological regions by microautoradiography. Deposition of lignin in the tracheid cell wall of compression wood occurred in the order: p-hydroxyphenyl, guaiacyl and syringyl lignin, which is the same order as observed in normal wood. However, the period of lignification in the compression wood was quite different from those of normal and opposite woods. The p-hydroxyphenyl units were deposited mainly in the early stage of cell wall formation in compound middle lamella in normal and opposite woods, while in compression wood, they were formed in both the compound middle lamella and the secondary wall. The most intensive lignification was observed during the formation of the S2 layer, proceeding from the outer to inner S2 layers for a long period in compression wood. In the normal or opposite woods, in contrast, the lignification became active after formation of S3 had begun, then proceeded uniformly in the secondary wall and ended after a short period.

Notes: Summary Differential blocking of α motor fibers was investigated in single fiber recordings when slowly rising direct current was applied to the gastrocnemius nerve in the cat. 18 out of the 26 (69.2%) L7 ventral root filaments, each of which contained 2–5 single α, or γ motor fibers, or both, showed consecutive blocking from thicker to thinner fibers with increase of polarizing current. In the remaining 8 filaments (30.8%) thicker and thinner fibers were blocked almost simultaneously, or the order was reversed. The relation between the strength of the blocking current and conduction velocity is summarized on 30 α and 41 γ fibers. The blocking current of each single fibers was shown to be inversely proportional to 2.01 power of conduction velocity (correlation coefficient −0.71). A regression line was also drawn for α fibers alone, its correlation coefficient being −0.60. Concerning prolongation of latencies of 82 single fibers (39 α and 43 γ), it was shown that the faster the conduction velocity, the smaller was the prolongation of latencies. In no experiments did the prolongation of latencies of single α fibers exceed the latency range of the mass α volley. Moreover, single α fibers were blocked earlier than or almost simultaneously with the mass α volley.

Notes: Abstract Previously, one of the authors proposed a new hypothesis on the organization of synaptic connections, and constructed a model of self-organizing multi-layered neural network “cognitron” (Fukushima, 1975). the cognitron consists of a number of neural layers with similar structure connected in a cascade one after another. We have modified the structure of the cognitron, and have developed a new network having an ability of associative memory. The new network, named a feedback-type cognitron, has not only the feedforward connections as in the conventional cognitron, but also modifiable feedback connections from the last-layer cells to the front-layer ones. This network has been simulated on a digital computer. If several stimulus patterns are repeatedly presented to the network, the interconnections between the cells are gradually organized. The feedback connections, as well as the conventional feedforward ones, are self-organized depending on the characteristies of the externally presented stimulus patterns. After adequate number of stimulus presentations, each cell usually acquires the selective responsiveness to one of the stimulus patterns which have been frequently given. That is, every different stimulus pattern becomes to elicit an individual response to the network. After the completion of the self-organization, several stimulus patterns are presented to the network, and the responses are observed. Once a stimulus is given to the network, the signal keeps circulating in the network even after cutting off the stimulus, and the response gradually changes. Even though an imperfect or an ambiguous pattern is presented, the response usually converges to one of the patterns which have been frequently given during the process of self-organization. In some cases, however, a new pattern which has never been presented before, emerges. It is seen that this feedback-type cognitron has characteristics quite similar to some functions of the brain, such as the associative recall of memory, or the creation of a new idea by intuition.

Notes: Abstract Previously, the authors proposed a model of neural network extracting binocular parallax (Hirai and Fukushima, 1975). It is a multilayered network whose final layers consist of neural elements corresponding to “binocular depth neurons” found in monkey's visual cortex. The binocular depth neuron is selectively sensitive to a binocular stimulus with a specific amount of binocular parallax and does not respond to a monocular one. As described in the last chapter of the previous article (Hirai and Fukushima, 1975), when a binocular pair of input patterns consist of, for example, many vertical bars placed very closely to each other, the binocular depth neurons might respond not only to correct binocular pairs, but also to incorrect ones. Our present study is concentrated upon how the visual system finds correct binocular pairs or binocular correspondence. It is assumed that some neural network is cascaded after the binocular depth neurons and finds out correct binocular correspondence by eliminating the incorrect binocular pairs. In this article a model of such neural network is proposed. The performance of the model has been simulated on a digital computer. The results of the computer simulation show that this model finds binocular correspondence satisfactorily. It has been demonstrated by the computer simulation that this model also explains the mechanism of the hysteresis in the binocular depth perception reported by Fender and Julesz (1967)

Notes: Summary Recent studies have shown that the interstitial nucleus of Cajal (INC) in the midbrain reticular formation is involved in the conversion of vertical semicircular canal signals into eye position during vertical vestibuloocular reflexes. Secondary vestibulo-ocular relay neurons related to the vertical canals, which constitute the majority of output neurons sending signals from the vestibular nuclei directly to the oculomotor nuclei, have been shown to project axon collaterals to the region within and near the INC. To understand how the INC is involved in the signal conversion, latencies of response of neurons in the INC region to electrical stimulaton of the vestibular nerve were examined in alert cats. The responses of 96 cells whose activity was clearly modulated by sinusoidal pitch rotation (at 0.31 Hz) were analyzed. These included 41 cells whose activity was closely correlated with vertical eye movement (38 burst-tonic and 3 tonic neurons), and 55 other cells (called pitch cells as previously). Twenty nine of the 96 cells (30%) were activated at disynaptic latencies following single shock stimulation of the contralateral vestibular nerve. Disynaptically activated cells were significantly more frequent for pitch cells than for eye movement-related cells (25/55 = 45% vs 4/41 = 10%; p 〈 0.001, Chi-square test). Conversely, cells that did not receive short-latency activation (〈 6 ms) were more frequent among eye movement-related cells than pitch cells (26/41 = 63% vs 13/55 = 24%; p 〈 0.001, Chi-square test). Pitch cells showed significantly less phase lag (re head acceleration) than eye movement-related cells during sinusoidal pitch rotation (mean ± SD 124° ± 17° vs 138° ± 14°. p 〈 0.01, t-test). These results suggest that 1) cells in the INC region other than burst-tonic and tonic neurons mainly receive direct inputs from secondary vestibulo-ocular relay neurons, and that 2) vertical canal signals reach eye movement-related neurons mainly polysynaptically.

Notes: Summary 1. Maximal activation directions of vertical burst-tonic and tonic neurons in the region of the interstitial nucleus of Cajal (INC) were examined in alert cats during vertical vestibulo-ocular reflex induced by sinusoidal rotation (at 0.11 Hz±10 deg, or 0.31 Hz±5 deg) in a variety of vertical planes using a null point analysis. The results were compared with the angles of anatomical and functional planes of vertical canals reported by Blanks et al. (1972) and Robinson (1982), and with the angles of vertical eye muscles measured in this study and by Ezure and Graf (1984). 2. Maximal activation directions of 23 cells (21 burst-tonic and 2 tonic neurons) were determined from their responses during rotation in 4 or more different vertical planes. All cells showed sinusoidal gain curves and virtually constant phase values except near the null regions, suggesting that their responses were evoked primarily by canal inputs. Phase values of 5 cells near the null regions depended on the rotation plane, suggesting additional otolith inputs. We used a measurement error range of ±10 deg for calculating the maximal activation directions from the null regions of individual cells and the values of error ranges of null calculation. Of the 23, the maximal activation directions of 7 cells were outside the measurement error ranges of vertical eye muscle angles and within the ranges of vertical canal angles (class A), those of 5 cells were within the ranges of eye muscle angles and outside the ranges of vertical canal angles (class B), and those of the remaining 11 cells were in the overlapping ranges for both angles (class C). Even if only the cells in which 5 or more measurement points were taken to determine maximal activation directions (n = 15), the results were similar. During vertical rotation with the head orientation +60 deg off the pitch plane, dissociation of cell activity and vertical compensatory eye movement was observed in 5 cells in class A or C that had null angles near +45 deg. These results suggest that the cells in class A and B carried individual vertical canal and oculomotor signals, respectively, although it is difficult to tell for the majority of cells (class C) which signals they reflected. Some cells in class A and C were antidromically activated from the medial longitudinal fasciculus at the level of abducens nucleus, suggesting that the signals carried by these cells may be sent to the lower brainstem. 3. Most burst-tonic neurons did not respond to horizontal rotation; significant responses were obtained in only 3 of 10 cells tested for which the gain was only 14–17% of their maximal vertical gain. There was no clear difference in gain or phase values of the responses to vertical rotation, or in eye position sensitivity (during spontaneous saccades) between cells whose responses coincided with individual vertical canal angles and those matching the angles of vertical recti muscles. The values of phase lag (re head acceleration during pitch rotation) and eye position sensitivity of these cells are still smaller compared to those of extraocular motoneurons reported by Delgado-Garcia et al. (1986), although they were larger than those of secondary vestibulo-ocular neurons (Perlmutter et al. 1988). All these results suggest that the signals carried by burst-tonic and tonic neurons in the INC region are different from oculomotor signals. 4. Similar analysis was done for comparison for 19 other cells that did not show close correlation with spontaneous eye movement but whose activity was clearly modulated by pitch rotation (pitch cells). More than a half (10/19) had maximal activation directions outside the measurement error ranges of individual vertical canal angles, and many shifted towards roll. Horizontal rotation produced responses with higher gain than burst-tonic neurons, suggesting a difference in the spatial response properties of burst-tonic and tonic neurons on one hand and pitch cells on the other.