The atmospheric scattering and absorption gives rise to the natural phenomenon of haze, which severely affects the visibility of scenery. Thus, the image taken by the camera can easily lead to over ...brightness and ambiguity. To resolve an ill-posed and intractable problem of single image dehazing, we propose a straightforward but remarkable prior-atmospheric illumination prior in this paper. The extensive statistical experiments for different colorspaces and theoretical analyses indicate that the atmospheric illumination in hazy weather mainly has a great influence on the luminance channel in YCrCb colorspace, and has less impact on the chrominance channels. According to this prior, we try to maintain the intrinsic color of hazy scene and enhance its visual contrast. To this end, we apply the multiscale convolutional networks that can automatically identify hazy regions and restore deficient texture information. Compared with previous methods, the deep CNNs not only achieve an end-to-end trainable model, but also accomplish an easy image-to-image system architecture. The extensive comparisons and analyses with existing approaches demonstrate that the proposed approach achieves the state-of-the-art performance on several dehazing effects.
Vasculature architecture of the brain can provide revealing information about mental and neurological function and disease. Fluorescence imaging in the second near-infrared (NIR-II) regime with less ...light scattering is a more promising method for detecting cortical vessels than traditional visible and NIR-I modes.
: Clinically approved dye indocyanine green (ICG) was used for NIR-II fluorescence imaging. Here, for the first time, we developed two NIR-II fluorescence microscopy systems for brain vasculature imaging in macaque monkeys. The first is a wide-field microscope with high temporal resolution for measuring blood flow velocity and cardiac impulse period, while the second is a high spatial resolution confocal microscope producing three-dimensional maps of the cortical microvascular network. Both were designed with flexibility to image various cortical locations on the head.
: Here, ICG was proved to have high brightness in NIR-II region and an 8-fold QY increase in serum than in water. We achieved cerebrovascular functional imaging of monkey with high temporal resolution (25 frames/second) with wide-field microscope. The blood flow velocity of capillaries can be precisely calculated and the cardiac impulse period can be monitored as well.
structural imaging of cerebrovasculature was accomplished with both high spatial lateral resolution (~8 µm) and high signal to background ratio (SBR). Vivid 3D reconstructed NIR-II fluorescence confocal microscopic images up to depth of 470 μm were also realized.
: This work comprises an important advance towards studies of neurovascular coupling, stroke, and other diseases relevant to neurovascular health in humans.
The early diagnosis of Alzheimer's disease (AD) can allow patients to take preventive measures before irreversible brain damage occurs. It can be seen from cross-sectional imaging studies of AD that ...the features of the lesion areas in AD patients, as observed by magnetic resonance imaging (MRI), show significant variation, and these features are distributed throughout the image space. Since the convolutional layer of the general convolutional neural network (CNN) cannot satisfactorily extract long-distance correlation in the feature space, a deep residual network (ResNet) model, based on spatial transformer networks (STN) and the non-local attention mechanism, is proposed in this study for the early diagnosis of AD. In this ResNet model, a new Mish activation function is selected in the ResNet-50 backbone to replace the Relu function, STN is introduced between the input layer and the improved ResNet-50 backbone, and a non-local attention mechanism is introduced between the fourth and the fifth stages of the improved ResNet-50 backbone. This ResNet model can extract more information from the layers by deepening the network structure through deep ResNet. The introduced STN can transform the spatial information in MRI images of Alzheimer's patients into another space and retain the key information. The introduced non-local attention mechanism can find the relationship between the lesion areas and normal areas in the feature space. This model can solve the problem of local information loss in traditional CNN and can extract the long-distance correlation in feature space. The proposed method was validated using the ADNI (Alzheimer's disease neuroimaging initiative) experimental dataset, and compared with several models. The experimental results show that the classification accuracy of the algorithm proposed in this study can reach 97.1%, the macro precision can reach 95.5%, the macro recall can reach 95.3%, and the macro F1 value can reach 95.4%. The proposed model is more effective than other algorithms.
There is increasing evidence for the vulnerability of specific retinal ganglion cell (RGC) types in those with glaucoma and in animal models. In addition, the P2X7-receptor (P2X7-R) has been ...suggested to contribute to RGC death following stimulation and elevated IOP, though its role in RGC dysfunction prior to death has not been examined. Therefore, we examined the effect of an acute, non-ischemic intraocular pressure (IOP) insult (50 mmHg for 30 min) on RGC function in wildtype mice and P2X7-R knockout (P2X7-KO) mice. We examined retinal function using electroretinogram recordings and individual RGC responses using multielectrode arrays, 3 days following acute IOP elevation. Immunohistochemistry was used to examine RGC cell death and P2X7-R expression in several RGC types. Acute intraocular pressure elevation produced pronounced dysfunction in RGCs; whilst other retinal neuronal responses showed lesser changes. Dysfunction at 3 days post-injury was not associated with RGC loss or changes in receptive field size. However, in wildtype animals, OFF-RGCs showed reduced spontaneous and light-elicited activity. In the P2X7-KO, both ON- and OFF-RGC light-elicited responses were reduced. Expression of P2X7-R in wildtype ON-RGC dendrites was higher than in other RGC types. In conclusion, OFF-RGCs were vulnerable to acute IOP elevation and their dysfunction was not rescued by genetic ablation of P2X7-R. Indeed, knockout of P2X7-R also caused ON-RGC dysfunction. These findings aid our understanding of how pressure affects RGC function and suggest treatments targeting the P2X7-R need to be carefully considered.
Ultra‐high Field (≥7T) functional magnetic resonance imaging (UHF‐fMRI) provides opportunities to resolve fine‐scale features of functional architecture such as cerebral cortical columns and layers, ...in vivo. While the nominal resolution of modern fMRI acquisitions may appear to be sufficient to resolve these features, several common data preprocessing steps can introduce unwanted spatial blurring, especially those that require interpolation of the data. These resolution losses can impede the detection of the fine‐scale features of interest. To examine quantitatively and systematically the sources of spatial resolution losses occurring during preprocessing, we used synthetic fMRI data and real fMRI data from the human visual cortex—the spatially interdigitated human V2 “thin” and “thick” stripes. The pattern of these cortical columns lies along the cortical surface and thus can be best appreciated using surface‐based fMRI analysis. We used this as a testbed for evaluating strategies that can reduce spatial blurring of fMRI data. Our results show that resolution losses can be mitigated at multiple points in preprocessing pathway. We show that unwanted blur is introduced at each step of volume transformation and surface projection, and can be ameliorated by replacing multi‐step transformations with equivalent single‐step transformations. Surprisingly, the simple approaches of volume upsampling and of cortical mesh refinement also helped to reduce resolution losses caused by interpolation. Volume upsampling also serves to improve motion estimation accuracy, which helps to reduce blur. Moreover, we demonstrate that the level of spatial blurring is nonuniform over the brain—knowledge which is critical for interpreting data in high‐resolution fMRI studies. Importantly, our study provides recommendations for reducing unwanted blurring during preprocessing as well as methods that enable quantitative comparisons between preprocessing strategies. These findings highlight several underappreciated sources of a spatial blur. Individually, the factors that contribute to spatial blur may appear to be minor, but in combination, the cumulative effects can hinder the interpretation of fine‐scale fMRI and the detectability of these fine‐scale features of functional architecture.
In order to evaluate the strategies to reduce spatial resolution losses during fMRI data preprocessing for high resolution surface‐based columnar mapping, we quantified inadvertent blur using both synthetic fMRI data and real fMRI data from human visual cortex, the spatially interdigitated V2 “thin” and “thick” stripes. Results surprisingly show that the simple method of volume upsampling can effectively preserve spatial resolution, and we also highlight less well‐known sources of spatial nonuniform blur that are present during acquisition. These findings uncover several underappreciated sources of the spatial blur, which can hinder the interpretation of submillimeter fMRI and the detectability of these fine‐scale features of functional architecture.
The pulvinar in the macaque monkey contains three divisions: the medial pulvinar (PM), the lateral pulvinar (PL), and the inferior pulvinar (PI). Anatomical studies have shown that connections of PM ...are preferentially distributed to higher association areas, those of PL are biased toward the ventral visual pathway, and those of PI are biased with the dorsal visual pathway. To study functional connections of the pulvinar at mesoscale, we used a novel method called INS–fMRI (infrared neural stimulation and functional magnetic resonance imaging). This method permits studies and comparisons of multiple pulvinar networks within single animals. As previously revealed, stimulations of different sites in PL and PI produced topographically organized focal activations in visual areas V1, V2, and V3. In contrast, PM stimulation elicited little or diffuse response. The relative activations of areas V1, V2, V3A, V3d, V3v, V4, MT, and MST revealed that connections of PL are biased to ventral pathway areas, and those of PI are biased to dorsal areas. Different statistical values of activated blood‐oxygen‐level‐dependent responses produced the same center of activation, indicating stability of connectivity; it also suggests possible dynamics of broad to focal responses from single stimulation sites. These results demonstrate that infrared neural stimulation‐induced connectivity is largely consistent with previous anatomical connectivity studies, thereby demonstrating validity of our novel method. In addition, it suggests additional interpretations of functional connectivity to complement anatomical studies.
We have employed a novel method combining infrared laser neural stimulation (INS) and fMRI to study functional networks from the pulvinar to the visual cortex at mesoscale in vivo. We show that stimulations of different sites in the pulvinar produced topographically organized focal BOLD activations in visual areas. When the stimulation sites moved slightly (as shown in the upper panel of the graphical , sites a and b) in the pulvinar, the BOLD responses observed in the visual cortex shifted accordingly (lower panel).
This article grapples with the question: how do huangmei opera and kua-a opera listeners experience formal coherence? Both opera traditions abound with changing phrase lengths that subvert the ...anticipatory listening strategies familiar to Anglo-American theorists. However, these temporal variabilities do not appear to disturb local listeners’ sense of formal coherence. Instead, ethnographic interviews and musical analyses suggest that the temporal sensibilities of huangmei opera and kua-a opera listeners anchor in the cadence of linguistic sounds and, more broadly, in “timeways”—ideas and practices relating to how a community experiences, measures, and expresses time—that stem from a Dao-centered paradigm of worldmaking. The latter yields a conception of musical time that embraces changeability and the pursuit of auspicious timings.
Hydrogen sulfide (H
S) as an important biological gasotransmitter plays a pivotal role in many physiological and pathological processes. The sensitive and quantitative detection of H
S level is ...therefore crucial for precise diagnosis and prognosis evaluation of various diseases but remains a huge challenge due to the lack of accurate and reliable analytical methods in vivo. In this work, we report a smart, H
S-responsive and depleting nanoplatform (ZNNPs) for quantitative and real-time imaging of endogenous H
S for early diagnosis and treatment of H
S-associated diseases. We show that ZNNPs exhibit unexpected NIR conversion (F
→ F
) and ratiometric photoacoustic (PA
/PA
) signal responsiveness towards H
S, allowing for sensitive and quantitative visualization of H
S in acute hepatotoxicity, cerebral hemorrhage model as well as colorectal tumors in living mice. ZNNPs@FA simultaneously scavenges the mitochondrial H
S in tumors leading to significant ATP reduction and severe mitochondrial damage, together with the activated photodynamic effect, resulting in efficient suppression of colorectal tumor growth in mice. We believe that this platform may provide a powerful tool for studying the vital impacts of H
S in related diseases.
The cover image is based on the Research Article Functional topography of pulvinar‐visual cortex networks in macaques revealed by INS‐fMRI by Toru Takahata et al., https://doi.org/10.1002/cne.25456
The use of high-field magnetic resonance spectroscopy (MRS) in multiple brain regions of a large population of human participants facilitates in vivo study of localized or diffusely altered brain ...metabolites in patients with first-episode psychosis (FEP) compared to healthy participants.
To compare metabolite levels in 5 brain regions between patients with FEP (evaluated within 2 years of onset) and healthy controls, and to explore possible associations between targeted metabolite levels and neuropsychological test performance.
Cross-sectional design used 7-T MRS at a research MR imaging facility in participants recruited from clinics at the Johns Hopkins Schizophrenia Center and the local population. Eighty-one patients who had received a DSM-IV diagnosis of FEP within the last 2 years and 91 healthy age-matched (but not sex-matched) volunteers participated.
Brain metabolite levels including glutamate, glutamine, γ-aminobutyric acid (GABA), N-acetylaspartate, N-acetylaspartyl glutamate, and glutathione, as well as performance on neuropsychological tests.
The mean (SD) age of 81 patients with FEP was 22.3 (4.4) years and 57 were male, while the mean (SD) age of 91 healthy participants was 23.3 (3.9) years and 42 were male. Compared with healthy participants, patients with FEP had lower levels of glutamate (F1,162 = 8.63, P = .02), N-acetylaspartate (F1,161 = 5.93, P = .03), GABA (F1,163 = 6.38, P = .03), and glutathione (F1,162 = 4.79, P = .04) in the anterior cingulate (all P values are corrected for multiple comparisons); lower levels of N-acetylaspartate in the orbitofrontal region (F1,136 = 7.23, P = .05) and thalamus (F1,133 = 6.78, P = .03); and lower levels of glutathione in the thalamus (F1,135 = 7.57, P = .03). Among patients with FEP, N-acetylaspartate levels in the centrum semiovale white matter were significantly correlated with performance on neuropsychological tests, including processing speed (r = 0.48; P < .001), visual (r = 0.33; P = .04) and working (r = 0.38; P = .01) memory, and overall cognitive performance (r = 0.38; P = .01).
Seven-tesla MRS offers insights into biochemical changes associated with FEP and may be a useful tool for probing brain metabolism that ranges from neurotransmission to stress-associated pathways in participants with psychosis.
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