Search

Panoptic segmentation plays a crucial role in enabling robots to comprehend their surroundings, providing fine-grained scene understanding information for robots' intelligent tasks. Although existing methods have made some progress, they are prone to fail in areas with weak textures, small objects, etc. Inspired by biological vision research, we propose a cascaded contour-enhanced panoptic segmentation network called CCPSNet, attempting to enhance the discriminability of instances through structural knowledge. To acquire the scene structure, a cascade contour detection stream is designed, which extracts comprehensive scene contours using channel regulation structural perception module and coarse-to-fine cascade strategy. Furthermore, the contour-guided multi-scale feature enhancement stream is developed to boost the discrimination ability for small objects and weak textures. The stream integrates contour information and multi-scale context features through structural-aware feature modulation module and inverse aggregation technique. Experimental results show that our method improves accuracy on the Cityscapes (61.2 PQ) and COCO (43.5 PQ) datasets while also demonstrating robustness in challenging simulated real-world complex scenarios faced by robots, such as dirty cameras and rainy conditions. The proposed network promises to help the robot perceive the real scene. In future work, an unsupervised training strategy for the network could be explored to reduce the training cost. [ABSTRACT FROM AUTHOR]

The damage of the diabetic visual pathway is one of the main causes of blindness in diabetic patients. Visual pathways include anatomic parts from the retina to the occipital lobe. This study investigated the involvement of ferroptosis, a planned cell death brought on by the buildup of free iron in cells, in the impairment of visual pathways in diabetes mellitus. Streptozotocin (STZ) was used to construct a diabetic rat model. Pathological and ultrastructural changes of the occipital lobe, retina, and optic nerve were observed by Hematoxylin–Eosin (HE) staining and transmission electron microscopy (TEM). The expressions of Neuronal nuclei (NeuN), Glial fibrillary acidic protein (GFAP), and Glutathione Peroxidase 4 (GPX4) in the occipital lobe and retina were detected by immunofluorescence, and Western Blotting was used to identify the NeuN GFAP and GPX4 expressions in the occipital lobe. Iron content in the occipital lobe and retina was detected by Iron Assay Kit. The success rate of the diabetic rat model was 93.3%. In the diabetic group, the cells of the occipital lobe and retina were arranged disorderly, and the boundaries were unclear. The membrane of the occipital lobe, retina, and optic nerve was broken, some vacuoles were observed, mitochondrial morphology was changed, swelling was observed, and the mitochondrial ridge disappeared. There was a large increase in GFAP expression and iron concentration and a significant decrease in the expression of NeuN, and GPX4 in the retina and occipital lobe. Ferroptosis plays an important role in visual pathway damage in diabetes, and GPX4 regulates this process. [ABSTRACT FROM AUTHOR]

Edge detectors based on deep learning have good performance, but they lack efficient inference. We propose a lightweight edge detection network called BiCC (Bi-directional Complementary Cascade) that is inspired by the biological visual system. First, we design a bi-directional encoder that operates in parallel from shallow to deep and from deep to shallow, which simulates the first and second pathways of the biological visual system and their interactions. In addition to the bottom-up encoding, the encoder also incorporates top-down encoding of features. It starts from high-level global semantics and progressively refines them down to low-level local detail features, guiding and correcting the extraction of low-level features. This enhances the modeling of context. There is both a bottom-up feature extraction as well as a top-down refinement and correction, forming a bi-directional information feedback and propagation. Next, inspired by the complex cells in the primary visual cortex, we propose a highly integrative multi-scale decoder to fuse features and generate contour images. BiCC has a very small parameter size and does not require pre-training. On the BSDS500 dataset, it achieves an ODS F-measure of 0.809 and a high inference efficiency of up to 255 FPS, far exceeding other methods. Considering both performance and efficiency, our method is competitive. [ABSTRACT FROM AUTHOR]

Psychedelics like LSD (Lysergic acid diethylamide) and psilocybin are known to modulate perceptual modalities due to the activation of mostly serotonin receptors in specific cortical (e.g., visual cortex) and subcortical (e.g., thalamus) regions of the brain. In the visual domain, these psychedelic modulations often result in peculiar disturbances of viewed objects and light and sometimes even in hallucinations of non-existent environments, objects, and creatures. Although the underlying processes are poorly understood, research conducted over the past twenty years on the subjective experience of psychedelics details theories that attempt to explain these perceptual alterations due to a disruption of communication between cortical and subcortical regions. However, rare medical conditions in the visual system like Charles Bonnet syndrome that cause perceptual distortions may shed new light on the additional importance of the retinofugal pathway in psychedelic subjective experiences. Interneurons in the retina called amacrine cells could be the first site of visual psychedelic modulation and aid in disrupting the hierarchical structure of how humans perceive visual information. This paper presents an understanding of how the retinofugal pathway communicates and modulates visual information in psychedelic and clinical conditions. Therefore, we elucidate a new theory of psychedelic modulation in the retinofugal pathway. [ABSTRACT FROM AUTHOR]

Geniculocalcarine fibers are thought to be exclusively ipsilateral. However, recent findings challenged this belief, revealing bilateral recruiting responses in occipitotemporoparietal regions upon unilateral stimulation of the lateral geniculate nucleus (LGN) in humans. This raised the intriguing possibility of bilateral projections to primary visual areas (V1). This study sought to explore the hypothetical decussation of the geniculocalcarine tract. 40 healthy individuals' 7T magnetic resonance images from the Human Connectome Project were examined. Employing MRtrix3 software with the constrained spherical deconvolution algorithm, scans were processed. LGN served as the seed region and contralateral regions of interest (splenium of the corpus callosum, posterior commissure, LGN, V1, pulvinar, and superior colliculus) were defined to reconstruct the hypothetical decussated fibers. Tractography included contralateral V1 as the target region in all segmentations, excluding ipsilateral V1 to eliminate fibers leading to or originating from this area. Additionally, a segmentation of the tract originating from LGN and projecting to the ipsilateral V1 was performed. Mean fraction anisotropy and mean diffusivity metrics were extracted from the density maps. Observations revealed a substantial volume of decussated fibers between LGN and contralateral V1 via the splenium of the corpus callosum, albeit much smaller than ipsilateral fibers. The volume of ipsilateral fibers was similar in both sides. Left LGN-originating decussated fibers were more than double those originating from the right LGN. Tract segmentation to other regions of interests yielded no fibers. This study suggests a partial decussation of the fibers between LGN and V1, likely constituting the geniculocalcarine tract. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the combined performance of orbital MRI and intracranial visual pathway diffusion kurtosis imaging (DKI) in diagnosing dysthyroid optic neuropathy (DON). Methods: We retrospectively enrolled 61 thyroid-associated ophthalmopathy (TAO) patients, including 25 with DON (40 eyes) and 36 without DON (72 eyes). Orbital MRI–based apical muscle index (MI), diameter index (DI) of the optic nerve (ON), area index (AI) of the ON, apparent diffusion coefficient (ADC) and signal intensity ratio (SIR) of the ON, DKI-based kurtosis fractional anisotropy (KFA) and mean kurtosis (MK) of the optic tract (OT), optic radiation (OR), and Brodmann areas (BAs) 17, 18, and 19 were measured and compared between groups. The diagnostic performances of models were evaluated using receiver operating characteristic curve analyses and compared using the DeLong test. Results: TAO patients with DON had significantly higher apical MI, apical AI, and SIR of the ON, but significantly lower ADC of the ON than those without DON (p < 0.05). Meanwhile, the DON group exhibited significantly lower KFA across the OT, OR, BA17, BA18, and BA19 and lower MK at the OT and OR than the non-DON group (p < 0.05). The model integrating orbital MRI and intracranial visual pathway DKI parameters performed the best in diagnosing DON (AUC = 0.926), with optimal diagnostic sensitivity (80%) and specificity (94.4%), followed by orbital MRI combination (AUC = 0.890), and then intracranial visual pathway DKI combination (AUC = 0.832). Conclusion: Orbital MRI and intracranial visual pathway DKI can both assist in diagnosing DON. Combining orbital and intracranial imaging parameters could further optimize diagnostic efficiency. Clinical relevance statement: The novel finding could bring novel insights into the precise diagnosis and treatment of dysthyroid optic neuropathy, accordingly, contributing to the improvement of the patients' prognosis and quality of life in the future. Key Points: • Orbital MRI and intracranial visual pathway diffusion kurtosis imaging can both assist in diagnosing dysthyroid optic neuropathy. • Combining orbital MRI and intracranial visual pathway diffusion kurtosis imaging optimized the diagnostic efficiency of dysthyroid optic neuropathy. [ABSTRACT FROM AUTHOR]

To investigate the involvement of the visual cortex in improving freezing of gait (FoG) after subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson's disease (PD) patients using whole-brain seed-based functional connectivity. A total of 66 PD patients with FoG who underwent bilateral STN-DBS were included in our study. Patients were divided into a FoG responder group and an FoG nonresponder group according to whether FoG improved 1 year after DBS. We compared the differences in clinical characteristics, brain structural imaging, and seed-based functional connectivity between the 2 groups. The locations of active contacts were further analyzed. All PD patients benefited from STN-DBS. No significant differences in the baseline characteristics or brain structures were found between the 2 groups. Seed-based functional connectivity analysis revealed that better connectivity in bilateral primary visual areas was associated with better clinical improvement in FoG (P < 0.05 familywise error corrected). Further analysis revealed that this disparity was associated with the location of the active contacts within the rostral region of the sensorimotor subregion in the FoG responder group, in contrast to the findings in the FoG nonresponder group. This study suggested that DBS in the rostral region of the STN sensorimotor subregion may alleviate FoG by strengthening functional connectivity in primary visual areas, which has significant implications for guiding surgical strategies for FoG in the future. [ABSTRACT FROM AUTHOR]

Optical coherence tomography (OCT) is a non-invasive imaging technique based on the principle of low-coherence interferometry that captures detailed images of ocular structures. Multiple sclerosis (MS) is a neurodegenerative disease that can lead to damage of the optic nerve and retina, which can be depicted by OCT. The purpose of this pilot study is to determine whether macular OCT can be used as a biomarker in the detection of retrochiasmal lesions of the visual pathway in MS patients. We conducted a prospective study in which we included 52 MS patients and 27 healthy controls. All participants underwent brain MRI, visual field testing, and OCT evaluation of the thicknesses of the peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell layer (GCL), and macular inner plexiform layer (IPL). OCT measurements were adjusted for optic neuritis (ON). VF demonstrated poor capability to depict a retrochiasmal lesion identified by brain MRI (PPV 0.50). In conclusion, the OCT analysis of the macula appears to excel in identifying retrochiasmal MS lesions compared to VF changes. The alterations in the GCL and IPL demonstrate the most accurate detection of retrochiasmal visual pathway changes in MS patients. [ABSTRACT FROM AUTHOR]

AIM: To study the perception of first-order grating acuity and second-order spatial contrast sensitivity in patients with monocular anisometropia amblyopia.METHODS:A total of 715 children(715 eyes)diagnosed as monocular anisometropia amblyopia in our hospital from January 2018 to December 2022 were collected as amblyopia group, and 745 children(745 eyes)with normal corrected visual acuity were collected. The best corrected visual acuity(BCVA), first-order grating acuity and/or second-order spatial contrast sensitivity were measured, repectively. The perception ability of amblyopia patients to first-order grating acuity and second-order spatial contrast sensitivity were analyzed.RESULTS:There were significant differences between amblyopia group and normal control group in the perception of first-order grating acuity(11.58±6.10 vs. 20.27±3.47, P

Stroboscopic training enhances perceptual cognition and motor skills; however, neurophysiological mechanisms underlying this adaptation are not fully understood. This study aimed to investigate the effects of a six-week stroboscopic training program on the conductivity of the visual pathway in elite handball players, specifically related to their visual processing of retinal location and viewing conditions. The study included 22 handball players who were randomly assigned to an experimental or a control group. Both groups performed handball-specific in-situ tasks, but only the experimental group underwent stroboscopic training. Participants were assessed three times using visually evoked potential recordings measured by P100 implicit time and amplitude under three viewing conditions (dominant eye, nondominant eye, and binocular) and two retinal locations (extra-foveal and foveal vision) before and after the six-week training period, and again four weeks later. The results showed a significant TIME vs. GROUP effect of P100 implicit time for the dominant eye in extra-foveal vision (F2,40 = 5.20, p = 0.010, ηp2 = 0.206), extra-foveal binocular viewing (F2,40 = 3.32, p = 0.046, ηp2 = 0.142), and dominant eye foveal vision (F2,40 = 4.07, p = 0.025, ηp2 = 0.169). Stroboscopic training significantly improved early visual processing by reducing the P100 implicit time for the dominant eye and binocular vision, particularly in extra-foveal vision. The improvements were more noticeable in the short compared to the long term. [ABSTRACT FROM AUTHOR]

Objective　To investigate the microstructural changes in white matter of pituitary adenoma patients when the anterior visual pathway is compressed using diffusion tensor imaging（DTI） and discuss the clinical significance of these changes. Methods　Clinical and MRI data of 25 patients with pituitary adenomas and 25 matched healthy controls were prospectively included. Tract-based spatial statistics（ TBSS） was carried out to investigate difference in white matter integrity between 2 groups， which was measured using fractional anisotropy（FA）. A correlation between visual function evaluation index and regional FA value was examined using correlation analysis. Results　The FA values of bilateral optic radiations and inferior fronto-occipital fasciculus were significantly lower in the research group. The FA values of left optic radiation and inferior fronto-occipital fasciculus were positively correlated to mean deviation and visual field index， negatively correlated to patten standard deviation. The FA values of bilateral optic radiations and inferior fronto-occipital fasciculus were negatively correlated with Bulbo-pontine height. Conclusion　Patients with pituitary adenoma may experience damage to the bilateral optic radiation and inferior fronto-occipital fasciculus after compression of the anterior visual pathway， which may affect the patient’s visual function， further indicating that DTI can quantitatively assess the microstructure damage of the visual pathway in patients with pituitary adenoma. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the role of diffusion tensor imaging (DTI) of optic pathway in patients with idiopathic intracranial hypertension (IIH). Patients and Methods: This study included 41 IIH patients and 22 controls. They underwent DTI of the optic nerve (ON) and optic radiation (OR). Their fractional anostrophy (FA) and mean diffusivity (MD) were calculated by two reviewers and correlated with papilledema grade. Results: The optic nerve mean FA and MD of patients for reviewer-1 were 0.21 ± 0.047 and 2.189 ± 0.52 ×10−3 mm2/s and for reviewer-2 were 0.216 ± 0.047 and 2.17 ± 0.54 ×10−3 mm2/s. The mean ON FA and MD of controls for reviewer-1 were 0.33 ± 0.048 and 1.29 ± 0.26 ×10−3 mm2/s and for reviewer-2 were 0.34 ± 0.05 and 1.3 ± 0.26 ×10−3 mm2/s. There was significant difference in FA and MD between patients and controls (p < 0.00001). The OR mean FA and MD of patients for reviewer-1 were 0.61 ± 0.03 and 2.26 ± 0.55 ×10−3 mm2/s and for reviewer-2 were 0.6 ± 0.03 and 2.24 ± 0.57 ×10−3 mm2/s The mean OR FA and MD of controls for reviewer-1 were 0.6 ± 0.03 and 2.19 ± 0.49 ×10−3 mm2/s and for reviewer-2 were 0.6 ± 0.03 and 2.18 ± 0.49 ×10−3 mm2/s. There was no significant difference in FA and MD obtained in patients and controls. Both the FA and the MD of the ON showed strong correlation with the papilledema grade (r = −0.8 and 0.951, respectively). Conclusion: Our findings suggest that, IIH is associated mainly with pre-chiasmatic or ON involvement rather than post-chiasmatic parenchymal or OR involvement. DTI MD and FA parameters of the ON may be a reliable imaging biomarker for diagnosis of IIH and well correlated with papilledema grades. [ABSTRACT FROM AUTHOR]

Objective To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury. Methods Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential （VEP） and multifocal visual evolved potential （mfVEP） measurements, craniocerebral CT/MRI, and retinal optical coherence tomography （OCT） were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively. Results The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder （RAPD） and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway. Conclusion Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.

Visual perception is formed over time through the formation process and visual pathway. Exercise improves visual perception, but it is unclear whether exercise modulates nonspecifically or specifically the formation process and pathway of visual perception. Healthy young men performed the visual detection task in a backward masking paradigm before and during cycling exercise at a mild intensity or rest (control). The task presented gratings of a circular patch (target) and annulus (mask) arranged concentrically as a visual stimulus and asked if the presence and striped pattern (feature) of the target were detected. The relationship between the orientations of the gratings of the target and the mask included iso‐orientation and orthogonal orientation to investigate the orientation selectivity of the masking effect. The masking effect was evaluated by perceptual suppressive index (PSI). Exercise improved feature detection (∆PSI; Exercise: −20.6%, Control: 1.7%) but not presence detection (∆PSI; Exercise: 8.9%, Control: 29.6%) compared to the control condition, and the improving effect resulted from the attenuation of the non‐orientation‐selective (∆PSI; Exercise: −29.0%, Control: 16.8%) but not orientation‐selective masking effect (∆PSI; Exercise: −3.1%, Control: 11.7%). These results suggest that exercise affects the formation process of the perceptual feature of the target stimulus by suppressively modulating the neural networks responsible for the non‐orientation‐selective surround interaction in the subcortical visual pathways, whose effects are inherited by the cortical visual pathways necessary for perceptual image formation. In conclusion, our findings suggest that acute exercise improves visual perception transiently through the modulation of a specific formation process of visual processing. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forensic Medicine / Fayixue Zazhi is the property of Journal of Forensic Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The human visual pathway starts from the retina, passes through the retinogeniculate visual pathway, the optic radiation, and finally connects to the primary visual cortex. Diffusion MRI tractography is the only technology that can noninvasively reconstruct the visual pathway. However, complete and accurate visual pathway reconstruction is challenging because of the skull base environment and complex fiber geometries. Specifically, the optic nerve within the complex skull base environment can cause abnormal diffusion signals. The crossing and fanning fibers at the optic chiasm, and a sharp turn of Meyer's loop at the optic radiation, contribute to complex fiber geometries of the visual pathway. A fiber trajectory distribution (FTD) function‐based tractography method of our previous work and several high sensitivity tractography methods can reveal these complex fiber geometries, but are accompanied by false‐positive fibers. Thus, the related studies of the visual pathway mostly applied the expert region of interest selection strategy. However, interobserver variability is an issue in reconstructing an accurate visual pathway. In this paper, we propose a unified global tractography framework to automatically reconstruct the visual pathway. We first extend the FTD function to a high‐order streamline differential equation for global trajectory estimation. At the global level, the tractography process is simplified as the estimation of global trajectory distribution coefficients by minimizing the cost between trajectory distribution and the selected directions under the prior guidance by introducing the tractography template as anatomic priors. Furthermore, we use a deep learning‐based method and tractography template prior information to automatically generate the mask for tractography. The experimental results demonstrate that our proposed method can successfully reconstruct the visual pathway with high accuracy. [ABSTRACT FROM AUTHOR]

Optic never fibers in the visual pathway play significant roles in vision formation. Damages of optic nerve fibers are biomarkers for the diagnosis of various ophthalmological and neurological diseases; also, there is a need to prevent the optic nerve fibers from getting damaged in neurosurgery and radiation therapy. Reconstruction of optic nerve fibers frommedical images can facilitate all these clinical applications. Although many computational methods are developed for the reconstruction of optic nerve fibers, a comprehensive review of these methods is still lacking. This paper described both the two strategies for optic nerve fiber reconstruction applied in existing studies, i.e., image segmentation and fiber tracking. In comparison to image segmentation, fiber tracking can delineate more detailed structures of optic nerve fibers. For each strategy, both conventional and AI-based approaches were introduced, and the latter usually demonstrates better performance than the former. Fromthe review, we concluded that AI-basedmethods are the trend for optic nerve fiber reconstruction and some new techniques like generative AI can help address the current challenges in optic nerve fiber reconstruction. [ABSTRACT FROM AUTHOR]

The pulvinar is a higher-order thalamic relay and a central component of the extrageniculate visual pathway, with input from the superior colliculus and visual cortex and output to all of visual cortex. Rodent pulvinar, more commonly called the lateral posterior nucleus (LP), consists of three highly-conserved subdivisions, and offers the advantage of simplicity in its study compared to more subdivided primate pulvinar. Little is known about receptive field properties of LP, let alone whether functional differences exist between different LP subdivisions, making it difficult to understand what visual information is relayed and what kinds of computations the pulvinar might support. Here, we characterized single-cell response properties in two V1 recipient subdivisions of rat pulvinar, the rostromedial (LPrm) and lateral (LPl), and found that a fourth of the cells were selective for orientation, compared to half in V1, and that LP tuning widths were significantly broader. Response latencies were also significantly longer and preferred size more than three times larger on average than in V1; the latter suggesting pulvinar as a source of spatial context to V1. Between subdivisons, LPl cells preferred higher temporal frequencies, whereas LPrm showed a greater degree of direction selectivity and pattern motion detection. Taken together with known differences in connectivity patterns, these results suggest two separate visual feature processing channels in the pulvinar, one in LPl related to higher speed processing which likely derives from superior colliculus input, and the other in LPrm for motion processing derived through input from visual cortex. SIGNIFICANCE STATEMENT: The pulvinar has a perplexing role in visual cognition as no clear link has been found between the functional properties of its neurons and behavioral deficits that arise when it is damaged. The pulvinar, called the lateral posterior nucleus (LP) in rats, is a higher order thalamic relay with input from the superior colliculus and visual cortex and output to all of visual cortex. By characterizing single-cell response properties in anatomically distinct subdivisions we found two separate visual feature processing channels in the pulvinar, one in lateral LP related to higher speed processing which likely derives from superior colliculus input, and the other in rostromedial LP for motion processing derived through input from visual cortex.

Bio-inspired computing is a powerful platform that develops intelligent machines based on principles of the behavioral and functional mechanisms of the human nervous system. Such machines can be critical tools in expert systems, speech recognition, pattern recognition, and machine vision. In this study, a retinal model is used as input layer of spiking network to convert image pixels to spike trains. The produced spikes are injected into a spiking neural network (SNN) as a second layer, which structure and functioning is inspired by real neuronal networks (i.e. excitatory and inhibitory neurotransmitters as AMPA and GABA currents and spiking neurons). Similarly, an unsupervised, spatial–temporal, and sparse spike-based learning mechanism based on learning processes in the brain was developed to train the spiking neurons in the output layer for recognizing patterns of MNIST and EMNIST datasets with very high accuracy (above 97%) and CIFAR10 with accuracy 92.9%. The proposed spiking pattern recognition network has higher classification accuracy than previous deep spiking networks and has advantages such as higher convergence speed, unsupervised learning, fewer numbers of hyper-parameters and network layers, and ability to learn with the limited number of training data. Finally, by changing the size and stride of the averaging windows in the visual pathway, we can train the network with only 10% of the training datasets, achieving accuracy similar or higher than state-of-the-art deep learning approaches. The ability to achieve high-performance accuracy in pattern recognition networks despite the limited number of training data is one of the most important challenges of neural networks in artificial intelligence. In summary, the novel bio-inspired neuronal network utilizes spiking trains and learns unsupervised and is capable of recognizing complex patterns, similar in performance to advanced neuronal networks using deep learning, and potentially can be implemented in neuromorphic hardware. [ABSTRACT FROM AUTHOR]

AimsWe compared feasibility, quality and outcomes of visual field (VF) testing in children with neuro-ophthalmic disease between the discontinued 'gold-standard' Goldmann and Octopus perimeters.MethodsChildren with neuro-ophthalmic disease, attending Great Ormond Street Hospital, London, were assessed using standardised protocols by one examiner in a single sitting, using Goldmann and Octopus kinetic perimetry. Outputs were classified to compare severity of loss and defect type. Test quality was assessed using both qualitative and quantitative methods.ResultsThirty children (40% female) aged 5-15 years participated. Goldmann perimetry was completed in full by 90.0% vs 72.4% for Octopus. Inability to plot the blind spot was the most common reason for not completing testing. Over 75% completed a test in ≤20 min. Duration was similar between perimeters (paired t-test, mean difference: 0.48min (-1.2, 2.2), p=0.559). The lowest quality tests were for Octopus perimetry in children

To combat retinal degeneration, healthy fetal retinal sheets have been successfully transplanted into both rodent models and humans, with synaptic connectivity between transplant and degenerated host retina having been confirmed. In rodent studies, transplants have been shown to restore responses to flashes of light in a region of the superior colliculus corresponding to the location of the transplant in the host retina. To determine the quality and detail of visual information provided by the transplant, visual responsivity was studied here at the level of visual cortex where higher visual perception is processed. For our model, we used the transgenic Rho-S334ter line-3 rat (both sexes), which loses photoreceptors at an early age and is effectively blind at postnatal day 30. These rats received fetal retinal sheet transplants in one eye between 24 and 40 d of age. Three to 10 months following surgery, visually responsive neurons were found in regions of primary visual cortex matching the transplanted region of the retina that were as highly selective as normal rat to stimulus orientation, size, contrast, and spatial and temporal frequencies. Conversely, we found that selective response properties were largely absent in nontransplanted line-3 rats. Our data show that fetal retinal sheet transplants can result in remarkably normal visual function in visual cortex of rats with a degenerated host retina and represents a critical step toward developing an effective remedy for the visually impaired human population.SIGNIFICANCE STATEMENT Age-related macular degeneration and retinitis pigmentosa lead to profound vision loss in millions of people worldwide. Many patients lose both retinal pigment epithelium and photoreceptors. Hence, there is a great demand for the development of efficient techniques that allow for long-term vision restoration. In this study, we transplanted dissected fetal retinal sheets, which can differentiate into photoreceptors and integrate with the host retina of rats with severe retinal degeneration. Remarkably, we show that transplants generated visual responses in cortex similar in quality to normal rats. Furthermore, transplants preserved connectivity within visual cortex and the retinal relay from the lateral geniculate nucleus to visual cortex, supporting their potential application in curing vision loss associated with retinal degeneration.

Background: The retina imaging and brain magnetic resonance imaging (MRI) can both reflect early changes in Alzheimer's disease (AD) and may serve as potential biomarker for early diagnosis, but their correlation and the internal mechanism of retinal structural changes remain unclear. This study aimed to explore the possible correlation between retinal structure and visual pathway, brain structure, intrinsic activity changes in AD patients, as well as to build a classification model to identify AD patients. Methods: In the study, 49 AD patients and 48 healthy controls (HCs) were enrolled. Retinal images were obtained by optical coherence tomography (OCT). Multimodal MRI sequences of all subjects were collected. Spearman correlation analysis and multiple linear regression models were used to assess the correlation between OCT parameters and multimodal MRI findings. The diagnostic value of combination of retinal imaging and brain multimodal MRI was assessed by performing a receiver operating characteristic (ROC) curve. Results: Compared with HCs, retinal thickness and multimodal MRI findings of AD patients were significantly altered (p < 0.05). Significant correlations were presented between the fractional anisotropy (FA) value of optic tract and mean retinal thickness, macular volume, macular ganglion cell layer (GCL) thickness, inner plexiform layer (IPL) thickness in AD patients (p < 0.01). The fractional amplitude of low frequency fluctuations (fALFF) value of primary visual cortex (V1) was correlated with temporal quadrant peripapillary retinal nerve fiber layer (pRNFL) thickness (p < 0.05). The model combining thickness of GCL and temporal quadrant pRNFL, volume of hippocampus and lateral geniculate nucleus, and age showed the best performance to identify AD patients [area under the curve (AUC) = 0.936, sensitivity = 89.1%, specificity = 87.0%]. Conclusion: Our study demonstrated that retinal structure change was related to the loss of integrity of white matter fiber tracts in the visual pathway and the decreased LGN volume and functional metabolism of V1 in AD patients. Transsynaptic axonal retrograde lesions may be the underlying mechanism. Combining retinal imaging and multimodal MRI may provide new insight into the mechanism of retinal structural changes in AD and may serve as new target for early auxiliary diagnosis of AD. [ABSTRACT FROM AUTHOR]

Introduction: schizophrenia is today accepted as a neurobiological disorder with strong neurocognitive components, and neuropsychological research is based on determining the specificity of neurocognitive patterns, which contributes to clarifying the neuroanatomical and neuropsychological systems underlying the disease, making a clinical contribution to the development of more effective rehabilitation measures. While cognitive dysfunction, including memory and attentional deficits, are well known in schizophrenia, basic sensory processing deficits are evident too. A primary approach to analyzing integrity of visual processing is the use of visual evoked potentials (VEPs). The VEPs have the advantage that they are nonbehavioral and so provide an objective measure of brain function. Visual evoked potentials (VEPs) abnormalities have been a fairly consistent finding in patients with schizophrenia, and these highlight the importance of sensory processing deficits, in addition to higher cognitive dysfunction, for understanding the pathophysiology of schizophrenia. Aim: to determine the difference of P100 latency parameters in patients with schizophrenia and migraine headache using visual evoked potentials (VEPs). Materials and methods: this was a prospective, comparative study conducted at the Clinic of Psychiatry and Clinic of Neurology of the Clinical Center University of Sarajevo (CCUS) and it included 80 patients of both sexes, from 21 to 67 years of age, classified into two groups. Results: multivariate analysis of variance was used to examine whether there is a statistically significant difference in the latency parameters of the P100 wave between the observed and control groups. The results indicate that there is a statistically significant difference in the latency parameters of the P100 wave-prolongation, the entire visual field of both eyes, the entire visual field-left eye, the right visual field-left eye, the left visual field-left eye in the group of patients with schizophrenia compared to the control group of respondents. Conclusion: little is known about the association of schizophrenia with the occipital lobe or whether the visual symptoms exacerbate if the occipital lobe is severely damaged is not yet known. Our study is useful to initiate new questions and recommendations for further studies, specifically on changes in the occipital lobe in the schizophrenic patient's brain. [ABSTRACT FROM AUTHOR]

Purpose: RE-PERG is altered in presence of primary neuronal degeneration of retinal ganglion cells, both in glaucoma and other diseases. A previous study showed that in a model of retrograde degeneration (vascular dementia) RE-PERG was normal. In this study, we enrolled patients with pituitary adenoma (PA) to evaluate RE-PERG findings in another model of retrograde degeneration compared with healthy controls (HC). Based on the outcome of the present and our previous studies with RE-PERG, and reviewing the literature, we discuss the physiopathology of glaucoma. Methods: Twelve PA patients and 14 age-matched HC were recruited. All participants performed visual field (VF) test, retinal nerve fiber layer (RNFL) and ganglion cells complex (GCC) thickness measurement by means of optical coherence tomography (OCT), visual evoked potentials (VEPs) and RE-PERG, a non-invasive, fast steady-state pattern electroretinogram (SS-PERG) sampled in five consecutive blocks of 130 events. Results: VEPs amplitude was significantly lower in PA with respect to HC (6.8± 0.6 vs 7.4± 0.6 μV; p=0.045). VEPs latency was higher in PA (123.2± 5.8 vs 103.6± 4.1 msec; p< 0.01). As for VF, mean defect (MD) and pattern standard deviation (PSD) were higher in PA (− 6.6± 2.6 vs − 0.01± 1.02 dB; p< 0.01 and 8.5± 3.1 vs 1.5± 0.3; p< 0.01, respectively). RNFL thickness was lower in PA (88± 8.1 vs 97± 9.3 μ; p=0.01). There was no statistically significant difference between PA and HC for RE-PERG. There was a significant correlation among MD, PSD, VEPs amplitude, PERG amplitude and RNFL thickness in the PA group, whereas no correlation was found with SDPh, which remains as normal as in the HC group. Conclusion: Our findings confirm that RE-PERG is not altered in retrograde degeneration. Based on the outcome of the present and our previous studies about RE-PERG and glaucoma, we assume that in glaucoma a double mechanism of retinal ganglion cells degeneration, both retrograde and primary, can coexist. [ABSTRACT FROM AUTHOR]

Amyloid-β (Aβ) deposition and Aβ-induced neurodegeneration appear in the retina and retinorecipient areas in the early stages of Alzheimer's disease (AD). Although these Aβ-related changes in the retina cause damage to the visual functions, no studies have yet revealed the alterations in the visual pathways of AD. Therefore, we investigated the alterations of visual circuits in the AD mouse model using anterograde tracer cholera toxin β subunits (CTβ). Moreover, we investigated the Aβ accumulation in the retina and retinorecipient areas and the neuronal loss, and synaptic degeneration in retinorecipient areas by immunofluorescent staining of 4- and 12-month-old female 5XFAD transgenic mice. Our results demonstrated that Aβ accumulation and neurodegeneration occurred in the retina and retinorecipient regions of early and late stages of the 5XFAD mice. Retinal efferents to the suprachiasmatic nucleus and lateral geniculate nucleus were impaired in the early stage of AD. Moreover, retinal connections to the dorsal lateral geniculate nucleus and superior colliculus were degenerated in the late-stage of AD. These findings reveal the Aβ-related pathology induced visual circuit disturbances at the mesoscale level in both the early and late stages of AD and provide anatomical and functional insights into the visual circuitry of AD. [ABSTRACT FROM AUTHOR]

Abstract Background RNFL thickness measured by optical coherence tomography (OCT) and visual pathway measured by diffusion tensor imaging (DTI) can be used to predict visual field recovery, respectively. However, the relationship between RNFL thickness and visual pathway injury in patients with pituitary adenoma (PA) remains unclear. This study aims to evaluate the combining DTI and OCT methods in observing the microstructural change in the visual pathway in patients with PA. Methods Twenty-nine patients who were diagnosed with PA were included in the study group, and 29 healthy subjects were included as the control group. OCT detected the thickness of circumpapillary retinal nerve fiber layer (CP-RNFL) and ganglion cell layer (GCL). DTI measured the values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC). Correlation between CP-RNFL and GCL thickness and FA and ADC values was analyzed in the study group. Results Compared with the control group, the FA values of the bilateral optic nerve, chiasma, bilateral optic tract, and left optic radiation in the study group were reduced, and the ADC values of the bilateral optic nerve and optic chiasma were increased. Correlation analysis showed that the FA value of the optic chiasma was positively correlated with the average thickness of RNFL, the CP-RNFL thickness in the nasal and temporal retinal quadrants in both eyes, as well as the thickness of macular ring GCL in the nasal, supra, and inferior quadrants. The FA values of the optic nerve, optic chiasma, optic tract, and optic radiation were positively correlated with CP-RNFL thickness in the nasal and temporal quadrants. Conclusion Combined DTI and OCT can provide a comprehensive understanding of the microscopic changes in the structure and function of the whole visual pathway in patients with PA.

Conceptually speaking, Synthetic Aperture Radar (SAR) microwave vision 3D imaging refers to fusing visual semantics into the SAR 3D imaging process to enhance the 3D imaging quality. For SAR Tomography (TomoSAR), it specifically means to reduce the needed observations by fully exploiting SAR visual semantics. However, what does it mean by visual semantics? From the viewpoint of visual perception, 3D structural information could be perceived from either monocular image or binocular images and the same scene could be perceived differently by different people. From the viewpoint of neurophysiology, depth perception from binocular or monocular vision has fundamentally different mechanism. Besides visual illusion phenomenon is omnipresent in daily life. Hence what kinds of visual semantics could be helpful for SAR 3D imaging from the computational point of view? What could be learnt from computer vision community to extract useful visual semantics from SAR images? This short note presents some preliminary discussions on such issues, a purely personal view on such vast topics.

BackgroundOcular ischemic syndrome (OIS), attributable to chronic hypoperfusion caused by marked carotid stenosis, is one of the important factors that cause ocular neurodegenerative diseases such as optic atrophy. The current study aimed to detect blood flow perfusion in a visual pathway by arterial spin labeling (ASL) and magnetic resonance imaging (MRI) for the differential diagnosis of OIS.MethodsThis diagnostic, cross-sectional study at a single institution was performed to detect blood flow perfusion in a visual pathway based on 3D pseudocontinuous ASL (3D-pCASL) using 3.0T MRI. A total of 91 participants (91 eyes) consisting of 30 eyes with OIS and 61 eyes with noncarotid artery stenosis-related retinal vascular diseases (39 eyes with diabetic retinopathy and 22 eyes with high myopic retinopathy) were consecutively included. Blood flow perfusion values in visual pathways derived from regions of interest in ASL images, including the retinal-choroidal complex, the intraorbital segments of the optic nerve, the tractus optics, and the visual center, were obtained and compared with arm-retinal circulation time and retinal circulation time derived from fundus fluorescein angiography (FFA). Receiver operating characteristic (ROC) curve analyses and the intraclass correlation coefficient (ICC) were performed to evaluate the accuracy and consistency.ResultsPatients with OIS had the lowest blood flow perfusion values in the visual pathway (all p < 0.05). The relative intraorbital segments of optic nerve blood flow values at post-labeling delays (PLDs) of 1.5 s (area under the curve, AUC = 0.832) and the relative retinal–choroidal complex blood flow values at PLDs of 2.5 s (AUC = 0.805) were effective for the differential diagnosis of OIS. The ICC of the blood flow values derived from the retinal–choroidal complex and the intraorbital segments of the optic nerve between the two observers showed satisfactory concordance (all ICC > 0.932, p < 0.001). The adverse reaction rates of ASL and FFA were 2.20 and 3.30%, respectively.Conclusion3D-pCASL showed that the participants with OIS had lower blood flow perfusion values in the visual pathway, which presented satisfactory accuracy, reproducibility, and safety. It is a noninvasive and comprehensive differential diagnostic tool to assess blood flow perfusion in a visual pathway for the differential diagnosis of OIS.

We used correlation analysis to examine whether changes in grey matter volume in patients correlated with clinical presentation. gray matter volume was markedly reduced in neovascular glaucoma patients than healthy controls in the following brain regions: left cingulum anterior/medial frontal gyrus; left middle frontal gyrus, orbital part; left inferior frontal gyrus, orbital part; superior temporal gyrus/right frontal inferior orbital part. VBM directly suggests that neovascular glaucoma patients have changed in the volume of multiple brain regions. These changes exist in brain areas related to the visual pathway, as well as other brain areas which are not related to vision. The alteration of specific brain areas are closely related to clinical symptoms such as increased intraocular pressure and optic nerve atrophy in neovascular glaucoma patients. In conclusion, neovascular glaucoma may cause paralgesia, anxiety, and depression in patients.

The ability to perceive visual objects with various types of transformations, such as rotation, translation, and scaling, is crucial for consistent object recognition. In machine learning, invariant object detection for a network is often implemented by augmentation with a massive number of training images, but the mechanism of invariant object detection in biological brains--how invariance arises initially and whether it requires visual experience--remains elusive. Here, using a model neural network of the hierarchical visual pathway of the brain, we show that invariance of object detection can emerge spontaneously in the complete absence of learning. First, we found that units selective to a particular object class arise in randomly initialized networks even before visual training. Intriguingly, these units show robust tuning to images of each object class under a wide range of image transformation types, such as viewpoint rotation. We confirmed that this "innate" invariance of object selectivity enables untrained networks to perform an object-detection task robustly, even with images that have been significantly modulated. Our computational model predicts that invariant object tuning originates from combinations of non-invariant units via random feedforward projections, and we confirmed that the predicted profile of feedforward projections is observed in untrained networks. Our results suggest that invariance of object detection is an innate characteristic that can emerge spontaneously in random feedforward networks. [ABSTRACT FROM AUTHOR]

Male-male social interactions exert a substantial impact on the transcriptional regulation of genes associated with aggression and mating behavior in male Drosophila melanogaster. Throughout our comprehensive genetic screening of aggression-related genes, we identified that the majority of mutants for these genes are associated with rival-induced and visually-oriented mating behavior, longer-mating-duration (LMD). The majority of mutants with upregulated genes in single-housed males significantly altered LMD behavior but not copulation latency, suggesting a primary regulation of mating duration. Single-cell RNA sequencing revealed that LMD-related genes are predominantly co-expressed with male-specific genes like dsx and Cyp6a20 in specific cell populations, especially in cone cells. Functional validation confirmed the roles of these genes in mediating LMD. Expression of LMD genes like Cyp6a20, Cyp4d21, and CrzR was enriched in cone cells, with disruptions in cone cell-specific expression of CrzR and Cyp4d21 leading to disrupted LMD. We also identified a novel gene, CG10026/Macewindu, that reversed LMD when overexpressed in cone cells. These findings underscore the critical role of cone cells as a pivotal site for the expression of genes involved in the regulation of LMD behavior. This study provides valuable insights into the intricate mechanisms underlying complex sexual behaviors in Drosophila., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America.)

Functional vision disorder (FVD) is a relatively common diagnosis in ophthalmic practice which can be difficult to make because of clinician's apprehension to miss organic pathology. We review the diagnostic approach to patients with FVD, organic mimics of FVD, its diagnostic and management strategies and associated cost burden. Patients with FVD typically present with visual acuity and/or field loss. Diagnostic work-up should include patient observation, detailed history, pupillary examination, dilated ophthalmoscopy, visual field testing and ganglion cell analysis of the macular complex. Most common organic mimickers of FVD are amblyopia, cortical blindness, retrobulbar optic neuritis, cone dystrophy and chiasmal tumours; however, all could be ruled out by structured diagnostic approach. For patients with unilateral visual loss, bottom-up refraction, fogging of the well-seeing eye in the phoropter, convex lens and base-down prism tests could aid in diagnosis. For patients claiming binocular vision loss, checking for eye movement during the mirror test or nystagmus elicited by an optokinetic drum can be helpful. Effective management of FVD involves reassurance, stress reduction and, if agreed on, management of comorbid anxiety and/or depression. The social cost of FVD is predominately economic as patients typically meet several healthcare providers over multiple visits and often undergo several neuroimaging studies before neuro-ophthalmology referral. Further, inappropriate granting of disability benefits confers additional stigma to patients with organic vision loss., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Myelination of the retinal nerve fibre layer (MNFL) is generally an incidental asymptomatic finding on fundus exam. While MNFL is thought to be a congenital and stationary finding, there have been cases of acquired and progressive MNFL reported. Here, we discuss a case where a girl in middle childhood presented with reading difficulties and was found to have normal vision and MNFL superior to the left optic disc. Over 5 years, the MNFL was observed to grow, and a new patch appeared inferior to the left disc. A Y-shaped cleft was detected in lamina cribrosa. The shape of the cleft suggested incomplete embryological closure of the optic cup and optic stalk. This case offers support for the concept that defects in lamina cribrosa allow oligodendrocyte precursor cells to enter the retina, where they may later proliferate and differentiate to form MNFL., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Thyroid eye disease (TED) is an organ-specific autoimmune disease secondary largely to hyperthyroid Graves' disease, which profoundly affects patients' visual function, appearance, and physical and mental well-being. Emerging neuroimaging studies have reported alterations in the brains of patients with TED, suggesting that the impact of this autoimmune disease may extend beyond the orbit. This systematic review aims to consolidate the neuroimaging evidence that describes the brain alterations of TED. We analyzed information from thirty-one related studies involving 1349 TED patients and 710 healthy controls, employing multimodal neuroimaging techniques such as structural magnetic resonance imaging (MRI), functional MRI, diffusion MRI, and metabolic MRI. These studies define the brain alterations in regions associated with vision, cognition, and emotion regulation, such as gray matter volume changes, altered functional connectivity and activity, and microstructural modifications, revealing the neurological impact of TED beyond the orbit. Notably, there was convergence across these studies indicating predominant abnormalities within the occipital and parietal lobes. This review underscores the critical role of advanced neuroimaging techniques in unraveling the complex neuropathological mechanism of TED, laying a foundation for future research and potential therapeutic targets., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Vision is a complex sense that is widely represented in the cortex and involves multiple pathways that can be affected by conditions amenable to surgical treatment. From a neurosurgical point of view, the treatment of major lesions affecting the optic nerve, such as tumours, intracranial hypertension, trauma and aneurysms, can be approached depending on the segment to be worked on and the surrounding structures to be manipulated. Therefore, surgical manipulation of the visual pathway requires a detailed knowledge of functional neuroanatomy. The aim of this review is to present the functional and microsurgical anatomy of the second cranial nerve, through illustrations and cadaveric dissections, to support the choice of the best surgical approach and avoid iatrogenic injuries. For this purpose, a literature search was performed using the PubMed database. Additionally, cadaveric dissections were performed on adult cadaver heads fixed with formaldehyde and injected with coloured silicone.

Optic tract lesions (OTL) are often difficult to diagnose. We suggest an algorithm to simplify the often-challenging diagnosis of OTL. Clinical and imaging data were retrospectively collected from the electronic files of 6 patients diagnosed with OTL at a tertiary medical center in 2016–2020. The series included 4 children and 2 adults with an OTL caused by a glioma (n = 5) or motor vehicle accident (n = 1). Magnetic resonance imaging (MRI) revealed a suprasellar glioma involving the chiasm and tract alone (n = 1) and the ipsilateral optic nerve (n = 2) and only optic tract (3). Perimetry showed incongruent homonymous hemianopia in 3 patients. In two patients, perimetry could only be performed in one eye, and demonstrated hemianopia. In one patient perimetry was unreliable. Fundus examination revealed bow-tie atrophy in all patients. On optical coherence tomography (OCT) of the peripapillary retinal nerve fiber layer (RNFL) horizontal thinning was observed in the contralateral eye (n = 6). By presenting the information in a predefined order—visual field damage, OCT RNFL thickness, and MRI—the diagnosis could be easily reached even in children, and when other structures like the chiasm were involved. Fundus photographs easily detect bow tie atrophy in children. Systematic presentation of the data in a predefined order can ease the diagnostic process of OTLs.

Purpose: Based on fMRI technology, we explored whether children with strabismus and amblyopia (SA) showed significant change in fractional amplitude of low-frequency fluctuation (fALFF) values in specific brain regions compared with healthy controls and whether this change could point to the clinical manifestations and pathogenesis of children with strabismus to a certain extent. Methods: We enrolled 23 children with SA and the same number matched healthy controls in the ophthalmology department of the First Affiliated Hospital of Nanchang University, and the whole brain was scanned by rs-fMRI. The fALFF value of each brain area was derived to examine whether there is a statistical difference between the two groups. Meanwhile, the ROC curve was made in a viewto evaluate whether this difference proves useful as a diagnostic index. Finally, we analyzed whether changes in the fALFF value of some specific brain regions are related to clinical manifestations. Results: Compared with HCs, children with SA presented decreased fALFF values in the left temporal pole: the superior temporal gyrus, right middle temporal gyrus, right superior frontal gyrus, and right supplementary motor area. Meanwhile, they also showed higher fALFF values in specific brain areas, which included the left precentral gyrus, left inferior parietal, and left precuneus. Conclusion: Children with SA showed abnormal fALFF values in different brain regions. Most of these regions were allocated to the visual formation pathway, the eye movement-related pathway, or other visual-related pathways, suggesting the pathological mechanism of the patient. [ABSTRACT FROM AUTHOR]

We report a case of late-onset Leber's hereditary optic neuropathy (LHON) with concurrent retinal detachment, mild retinal pigment epithelial changes, cataract and hyperintensity on fluid-attenuated inversion recovery magnetic resonance imaging affecting the entire retrobulbar visual pathway. We also documented that progression of the visual field defect correlated with retinal nerve fibre layer and ganglion cell layer-inner plexiform layer changes on optical coherence tomography. Our case provides further understanding of LHON as a disorder of the entire pre-geniculate pathways and also highlights that detailed history taking in addition to recognition of typical sequential optic disc appearance and visual field characteristics at different stages of LHON remain critical even in this era of modern imaging, autoimmune biomarkers and genetic testing. [ABSTRACT FROM AUTHOR]

The consequences of forceful rotational acceleration on the central nervous system are not fully understood. While traumatic brain injury (TBI) research primarily has focused on effects related to the brain parenchyma, reports of traumatic meningeal enhancement in TBI patients may possess clinical significance. The objective of this study was to evaluate the meninges and brain for changes in dynamic contrast enhancement (DCE) magnetic resonance imaging (MRI) following closed-head impact model of engineered rotational acceleration (CHIMERA)–induced cerebral insult. Adult male and female mice received one (1 × ; n = 19 CHIMERA, n = 19 Sham) or four (4 × one/day; n = 18 CHIMERA, n = 12 Sham) injuries. Each animal underwent three MRI scans: 1 week before injury, immediately after the final injury, and 1 week post-injury. Compared with baseline readings and measures in sham animals, meningeal DCE in males was increased after single impact and repetitive injury. In female mice, DCE was elevated relative to their baseline level after a single impact. One week after CHIMERA, the meningeal enhancement returned to below baseline for single injured male mice, but compared with uninjured mice remained elevated in both sexes in the multiple impact groups. Pre-DCE meningeal T2-weighted relaxation time was increased only after 1 × CHIMERA in injured mice. Since vision is impaired after CHIMERA, visual pathway regions were analyzed through imaging and glial fibrillary acidic protein (GFAP) histology. Initial DCE in the lateral geniculate nucleus (LGN) and superior colliculus (SC) and T2 increases in the optic tract (OPT) and LGN were observed after injury with decreases in DCE and T2 1 week later. Astrogliosis was apparent in the OPT and SC with increased GFAP staining 7 days post-injury. To our knowledge, this is the first study to examine meningeal integrity after CHIMERA in both male and female rodents. DCE-MRI may serve as a useful approach for pre-clinical models of meningeal injury that will enable further evaluation of the underlying mechanisms. [ABSTRACT FROM AUTHOR]