The Influence of Illumination Color on the Subjective Visual Recognition of Biological Specimens

[Background] Visual examination by the naked eye is integral to medical diagnosis and surgery. The illumination in conditioned color is widely used for visual inspection in the industry but has not been introduced to the biomedical context. The color that can enhance the visual recognition of individual tissues is still unknown. Therefore, we carried out a visual recognition experiment on biological specimens to determine the subjective preference for illumination color based on questionnaires. [Methods] Twenty healthy subjects were asked to compare the visual recognizability of several rat tissues between the illuminations in test colors and white. The rats were anesthetized, and the femoral vein and abdominal cavity were exposed. Seven tissues were selected for a visual recognition test. Illumination was generated using a multi-color LED light. The subjects observed the tissues under the illuminations of white and one of the test colors alternately and reported which illumination is suitable for visual recognition using a questionnaire. [Results] The analysis of the questionnaires showed that the blue test color was more effective than white illumination in the visual recognition of fine structures such as the branching of blood vessels and nerves, and red illumination disturbed the visual recognizability of the same tissues. On the other hand, the red but not the blue illumination improved the visual recognizability of the vein beneath the intact skin. As to the recognition of individual tissues in the abdominal cavity, the white illumination gave a better visual recognizability compared to every other test color. [Conclusion] This study shows that the illumination color influences the visual recognition of biological specimens and the adequate color for the visual recognition of specific tissue parts is distinct among biological specimens. Using the lighting system to make fine adjustments to the illumination color may be useful in medical diagnosis and surgery

Dissolved methane distribution in surface seawater and its controlling factors in mid- and high-latitudes in the Southern Ocean

第6回極域科学シンポジウム分野横断セッション：[IB1] 海氷域における生物地球化学的研究11月17日（火）　統計数理研究所 セミナー室1（D305

Dark Rearing Promotes the Recovery of Visual Cortical Responses but Not the Morphology of Geniculocortical Axons in Amblyopic Cat

Monocular deprivation (MD) of vision during early postnatal life induces amblyopia, and most neurons in the primary visual cortex lose their responses to the closed eye. Anatomically, the somata of neurons in the closed-eye recipient layer of the lateral geniculate nucleus (LGN) shrink and their axons projecting to the visual cortex retract. Although it has been difficult to restore visual acuity after maturation, recent studies in rodents and cats showed that a period of exposure to complete darkness could promote recovery from amblyopia induced by prior MD. However, in cats, which have an organization of central visual pathways similar to humans, the effect of dark rearing only improves monocular vision and does not restore binocular depth perception. To determine whether dark rearing can completely restore the visual pathway, we examined its effect on the three major concomitants of MD in individual visual neurons, eye preference of visual cortical neurons and soma size and axon morphology of LGN neurons. Dark rearing improved the recovery of visual cortical responses to the closed eye compared with the recovery under binocular conditions. However, geniculocortical axons serving the closed eye remained retracted after dark rearing, whereas reopening the closed eye restored the soma size of LGN neurons. These results indicate that dark rearing incompletely restores the visual pathway, and thus exerts a limited restorative effect on visual function

Developmental and visual input-dependent regulation of the CB1 cannabinoid receptor in the mouse visual cortex.

The mammalian visual system exhibits significant experience-induced plasticity in the early postnatal period. While physiological studies have revealed the contribution of the CB1 cannabinoid receptor (CB1) to developmental plasticity in the primary visual cortex (V1), it remains unknown whether the expression and localization of CB1 is regulated during development or by visual experience. To explore a possible role of the endocannabinoid system in visual cortical plasticity, we examined the expression of CB1 in the visual cortex of mice. We found intense CB1 immunoreactivity in layers II/III and VI. CB1 mainly localized at vesicular GABA transporter-positive inhibitory nerve terminals. The amount of CB1 protein increased throughout development, and the specific laminar pattern of CB1 appeared at P20 and remained until adulthood. Dark rearing from birth to P30 decreased the amount of CB1 protein in V1 and altered the synaptic localization of CB1 in the deep layer. Dark rearing until P50, however, did not influence the expression of CB1. Brief monocular deprivation for 2 days upregulated the localization of CB1 at inhibitory nerve terminals in the deep layer. Taken together, the expression and the localization of CB1 are developmentally regulated, and both parameters are influenced by visual experience

Synaptic localization of CB1 in V1.

<p>(A) Double immunofluorescent staining of CB1 (magenta) and MAP2 (green) in the upper layer of V1. CB1-positive varicosities presumably contact MAP2-positive dendrites (white arrowheads) and soma (asterisk, yellow arrowheads). Scale, 3 µm. (B) Double immunofluorescent staining of CB1 (magenta) and synaptophysin (green) in the upper layer of V1. Rectangles indicate the ROIs for the correlation coefficient (CC) analysis set on varicosities (orange) and shafts (blue) of CB1-positive structures. Scale, 1 µm. (C) Box and whisker plots showing the CC values of CB1 and synaptophysin in varicosities (var, n = 154 ROIs) and shafts (shaft, n = 140 ROIs). The horizontal lines show the 25th, 50th, and 75th percentiles, and the whiskers show the max and minimum values. Mann-Whitney U test, **: p<0.01. (D) Double immunofluorescent staining of CB1 (magenta) and VGAT, VGluT1, VGluT2 (green). Representative photographs of the upper layer (top row), middle layer (middle row), and deep layer (bottom row) of V1. Scale, 3 µm. (E) Box and whisker plots showing the CC values of CB1 and VGAT, VGluT1, or VGluT2 in each layer of V1 (n = 6 animals each; in the upper layer, n = 1226 ROIs (CB1/VGAT), 1203 ROIs (CB1/VGluT1), 1212 ROIs (CB1/VGluT2); in the middle layer, n = 492 ROIs (CB1/VGAT), 435 ROIs (CB1/VGluT1), 498 ROIs (CB1/VGluT2); in the deep layer, n = 1556 ROIs (CB1/VGAT), 1712 ROIs (CB1/VGluT1), 1492 ROIs (CB1/VGluT2)). The small circles indicate the outliers of the distribution of the CC values. In the box and whisker plots containing the outliers, the bottom of the whisker shows the value of the 25th percentile-1.5IQR. Statistical comparison among layers was performed by Bonferroni-corrected Mann-Whitney U test (***: p<0.00033).</p

Developmental change of CB1 expression in V1.

<p>(A) Representative western blots of CB1 and GAPDH in V1 at different postnatal ages. (B) Mean and SEM of CB1 blot densities of each age group (n = 8 hemispheres each from 4 animals, one-way factorial ANOVA, p<0.05, <i>post hoc</i> Tukey’s test, *: p<0.05). The blot densities were normalized to the mean density of P10. (C) CB1 immunostaining of the binocular region of V1 at postnatal ages indicated on top. Scale, 100 µm. (D) Layer distribution of CB1 immunoreactivity in the binocular region of V1 at different postnatal ages. Mean and SEM of CB1 signal intensity in each layer represented as the proportion to the all-layer intensity (n = 4 animals, one-way factorial ANOVA, p<0.05; layer II/III, p>0.05; layers IV, V, and VI, <i>post hoc</i> Tukey’s test, *: p<0.05, **: p<0.01).</p

Effects of dark rearing on CB1 expression.

<p>(A) Representative western blots of CB1 and GAPDH in V1. The blots of normal light/dark condition-reared (NR) and dark-reared (DR) mice at P30 and P50 are shown. (B) Mean and SEM of the blot density of CB1 (P30: n = 16 (NR) and 21 (DR) animals, P50: n = 5 (NR) and 5 (DR) animals; unpaired t-test, **: p<0.01). (C) Layer distribution of CB1 immunoreactivity in V1. Photographs represent immunostained sections of NR and DR animals at P30. Layer boundaries were determined in neighboring Nissl-stained sections. Scale, 100 µm. (D) CB1 immunoreactivity in individual layers of NR and DR animals at P30. Intensities in each layer are represented as the proportion to the all-layer intensities (two-way ANOVA, p>0.05). (E) Double immunofluorescent staining of CB1 (magenta) and VGAT, VGluT1 in the deep layer of V1 of NR (upper) and DR (lower) animals at P30. Scale, 3 µm. (F) Box and whisker plots showing the CC values of CB1 and VGAT, VGluT1 in the deep layer of NR and DR animals at P30 (n = 3 animals each; NR animals: n = 531 ROIs (CB1/VGAT), 244 ROIs (CB1/VGluT1), DR animals: n = 594 ROIs (CB1/VGAT), 343 ROIs (CB1/VGluT1), Mann-Whitney U test, *: p<0.05).</p

Distribution of CB1 in the visual cortex.

<p>(A) Low-magnification image of a coronal section of mouse brain at P30, immunostained for CB1. Inset, magnified view of LGN (*). Scale, 1 mm and 250 µm (inset). (B) Layer distribution of CB1 immunoreactivity in V1 (CB1). Layer boundaries were determined in neighboring Nissl-stained sections (Nissl). Scale, 100 µm. (C) Regional distribution of CB1 immunoreactivity in the visual cortex. Arrowheads indicate the boundaries between V1 and V2, determined in Nissl-stained sections. V2M: secondary visual cortex medial area, V2L: secondary visual cortex lateral area, MR: monocular region, BR: binocular region. Scale, 500 µm. (D) Horizontal profiles of CB1 immunoreactivity across the visual cortex. Signal intensity was measured in layer II/III. Dotted lines indicate region boundaries. The gray lines represent the profiles in individual sections obtained from an animal, and the black line represents the mean of them. AU indicates arbitrary units. (E) Mean signal intensity of CB1 in each visual cortical region. The error bars indicate SEM (n = 5 animals, one-way repeated measured ANOVA, p<0.05, <i>post hoc</i> Tukey’s test, *: p<0.05).</p