Amygdala and Cortex Relationships during Learning of a Sensory Discrimination Task.

During learning of a sensory discrimination task, the cortical and subcortical regions display complex spatiotemporal dynamics. During learning, both the amygdala and cortex link stimulus information to its appropriate association, for example, a reward. In addition, both structures are also related to nonsensory parameters such as body movements and licking during the reward period. However, the emergence of the cortico-amygdala relationships during learning is largely unknown. To study this, we combined wide-field cortical imaging with fiber photometry to simultaneously record cortico-amygdala population dynamics as male mice learn a whisker-dependent go/no-go task. We were able to simultaneously record neuronal populations from the posterior cortex and either the basolateral amygdala (BLA) or central/medial amygdala (CEM). Prior to learning, the somatosensory and associative cortex responded during sensation, while amygdala areas did not show significant responses. As mice became experts, amygdala responses emerged early during the sensation period, increasing in the CEM, while decreasing in the BLA. Interestingly, amygdala and cortical responses were associated with task-related body movement, displaying significant responses ∼200 ms before movement initiation which led to licking for the reward. A correlation analysis between the cortex and amygdala revealed negative and positive correlation with the BLA and CEM, respectively, only in the expert case. These results imply that learning induces an involvement of the cortex and amygdala which may aid to link sensory stimuli with appropriate associations.

Utility of Ultra-Wide-Field Imaging for Screening of AIDS-Related Cytomegalovirus Retinitis.

PURPOSE: To explore the potential use of ultra-wide-field (UWF) imaging for screening of cytomegalovirus retinitis (CMVR) in AIDS patients. METHODS: Ninety-four patients whose CD4 count was below 200 cells/µL were enrolled in a prospective study. Each patient underwent UWF imaging and indirect ophthalmoscopy. The main outcome measures were the concordance and detection rates of these 2 approaches and the sensitivity and specificity of UWF imaging. RESULTS: Twenty-seven eyes in 18 patients were diagnosed with CMVR by the indirect ophthalmoscopy. UWF imaging missed the diagnosis in 1 eye because of a zone 3 CMVR lesion. The UWF image showed several CMVR patterns and locations: hemorrhagic necrotizing lesion, granular lesion, frosted branch angiitis, and optic neuropathy lesion. The concordance of the 2 approaches was excellent for the diagnosis of CMVR, classification of CMVR pattern, and location of CMVR. The detection rates of UWF imaging and indirect ophthalmoscopy were 14.0% (26/186; 95% CI 0.089-0.190) and 14.5% (27/186; 95% CI 0.094-0.196), respectively (p = 1.000). The sensitivity and specificity of UWF imaging were 96.3 and 100%, respectively. CONCLUSIONS: UWF imaging is capable of documentation of different CMVR lesions and AIDS-related CMVR screening when examination by an ophthalmologist is not available.

Distribution of peripheral lesions identified by mydriatic ultra-wide field fundus imaging in diabetic retinopathy.

PURPOSE: To analyze the distribution of diabetic retinopathy (DR) lesions in an Indian population using ultra-wide field (UWF) fundus imaging. METHODS: Seven hundred fifteen subjects (1406 eyes) with diabetic retinopathy in India were enrolled in this multicenter, prospective, observational study using UWF pseudocolor imaging with Optos Daytona Plus (Optos plc, Dunfermline, Scotland, UK). Images were transmitted to Doheny Image Reading Center, Los Angeles, CA, for grading. The ETDRS grid was overlaid on stereographic projections of UWF images, and images were graded independently by 2 masked graders. Lesion distribution was graded as predominantly central (PCL) or predominantly peripheral (PPL) according to previous criteria, considering both lesion number and area. An image was graded as PPL if > 50% of the lesion area was seen in at least one peripheral field as compared with the corresponding ETDRS field. Diabetic retinopathy severity was also assessed based on the International Classification of Diabetic Retinopathy (ICDR) grading scale. The main outcome measures were lesion distribution (PPL versus PCL): overall and within specific fields in eyes with various grades of DR. RESULTS: Lesion distribution was rated to be PPL in 37% of eyes and PCL in 63% of eyes (P < 0.003). The frequency of a PPL distribution varied significantly across all ICDR severity levels, with frequencies of mild non-proliferative DR (NPDR) (30.9%), moderate NPDR (40.3%), severe NPDR (38.5%) and PDR (34.9%), P = 0.005. When assessing which individual fields were rated to show a PPL distribution, the frequency was greatest in field 4 and least in field 7. For any grade of DR, temporal fields showed the greatest PPL frequency, followed in order by the superior, inferior, and nasal fields (P < 0.001). Only 3.5% of eyes showed PPL distribution in all five peripheral fields. CONCLUSIONS: One-third of the UWF images showed a PPL distribution in this cohort with the temporal quadrant having the widest distribution of PPL. As the PPL distribution varied significantly between various grades of DR, UWF imaging may prove to be important for screening of referral warranted retinopathy.

Wide Field Spectral Imaging with Shifted Excitation Raman Difference Spectroscopy Using the Nod and Shuffle Technique.

Wide field Raman imaging using the integral field spectroscopy approach was used as a fast, one shot imaging method for the simultaneous collection of all spectra composing a Raman image. For the suppression of autofluorescence and background signals such as room light, shifted excitation Raman difference spectroscopy (SERDS) was applied to remove background artifacts in Raman spectra. To reduce acquisition times in wide field SERDS imaging, we adapted the nod and shuffle technique from astrophysics and implemented it into a wide field SERDS imaging setup. In our adapted version, the nod corresponds to the change in excitation wavelength, whereas the shuffle corresponds to the shifting of charges up and down on a Charge-Coupled Device (CCD) chip synchronous to the change in excitation wavelength. We coupled this improved wide field SERDS imaging setup to diode lasers with 784.4/785.5 and 457.7/458.9 nm excitation and applied it to samples such as paracetamol and aspirin tablets, polystyrene and polymethyl methacrylate beads, as well as pork meat using multiple accumulations with acquisition times in the range of 50 to 200 ms. The results tackle two main challenges of SERDS imaging: gradual photobleaching changes the autofluorescence background, and multiple readouts of CCD detector prolong the acquisition time.

Universal ocular screening of 481 infants using wide-field digital imaging system.

BACKGROUND: Universal ocular screening of infants is not a standard procedure in children's health care system in China. This pilot study investigated prevalence of ocular abnormalities of 6 weeks-age infants using wide-field digital imaging system. METHODS: Infants aged 6 weeks around were consecutively enrolled in a public hospital between April 2015 and August 2016. All the infants who were enrolled in the study underwent vision assessment, eye position examination, external eye check, pupillary light reflex, red reflex examination, anterior and posterior ocular segments were examined using flashlight, ophthalmoscope, and wide-field digital imaging system. RESULTS: A total of 481 infants at 45.1 ± 6.1 days after birth were enrolled in the study. 198 infants had abnormal findings (41.2%). Retinal white spots and retinal white areas were the most common findings (42.9% of abnormalities and 17.7% of all infants screened). The second major finding was retinal hemorrhage (16.2% of abnormalities and 6.7% of all infants screened). Other abnormal findings include retinal pigmentation, concomitant exotropia, neonatal dacryocystitis, retinopathy of prematurity, 'albinism-like fundus', congenital nasolacrimal duct obstruction, familial exudative vitreoretinopathy, immature retina, corneal dermoid tumor, large physiologic cupping of optic disc, congenital persistent pupillary membrane, entropion trichiasis, subconjunctival hemorrhage, congenital cataract, vitreous hemorrhage, ptosis and choroidal nevus. Intervention of any form was required in 22 infants, which accounted for 11.1% of abnormalities detected and 4.6% of all infants screened. CONCLUSION: Universal ocular screening is not only necessary for preterm infants but also for full-term infants. Addition of red reflex examination with wide-field digital imaging system can enhance the sensitivity of screening for ocular fundus abnormities. Further study with a long-term follow-up is needed in the future.

Colour imaging in the monitoring and documentation of choroidal naevi. Are Optomap colour images adequate for this purpose?

An audit project to evaluate and compare three different imaging systems used to photograph choroidal naevi and to determine whether the Optos Optomap(®) can be used as the only colour image capture system for monitoring and documenting choroidal naevi. A further aim was to assess whether existing protocols could be improved to accurately document position and appearance of choroidal naevi. Twenty patients with choroidal naevi were photographed on three different colour image capture systems. Colour images were taken on the Optomap(®) wide field P200MA camera; the Zeiss FF450plus(®) mydriatic camera and the Topcon TRC-NW6S(®). All images were reviewed retrospectively by a medical retina consultant (SD) who completed a questionnaire to determine the most effective photographic system(s) in demonstrating the location of the naevi and the features of the condition. The Optomap(®) was the most effective in pinpointing the location of the naevus and the Zeiss FF450plus mydriatic camera best captured the features of the naevus. The non-mydriatic camera was rated the least satisfactory for both tasks. The location of the naevus on the retina should determine the choice of modality. If it is possible to photograph the lesion and include the optic disc or central macula, then the mydriatic camera is considered the best modality for recording both the position and features of the pathology. However, if it is not possible, because of the location, to include both the disc or central macula with the lesion in the same frame, then the Optomap(®) should be used to photograph the naevus to record its position and ideally a colour image on the mydriatic camera should also be taken to record the appearance of the lesion.

Wide-field imaging in behaving mice as a tool to study cognitive function.

Cognitive functions are mediated through coordinated and dynamic neuronal responses that involve many different areas across the brain. Therefore, it is of high interest to simultaneously record neuronal activity from as many brain areas as possible while the subject performs a cognitive behavioral task. One of the emerging tools to achieve a mesoscopic field of view is wide-field imaging of cortex-wide dynamics in mice. Wide-field imaging is cost-effective, user-friendly, and enables obtaining cortex-wide signals from mice performing complex and demanding cognitive tasks. Importantly, wide-field imaging offers an unbiased cortex-wide observation that sheds light on overlooked cortical regions and highlights parallel processing circuits. Recent wide-field imaging studies have shown that multi-area cortex-wide patterns, rather than just a single area, are involved in encoding cognitive functions. The optical properties of wide-field imaging enable imaging of different brain signals, such as layer-specific, inhibitory subtypes, or neuromodulation signals. Here, I review the main advantages of wide-field imaging in mice, review the recent literature, and discuss future directions of the field. It is expected that wide-field imaging in behaving mice will continue to gain popularity and aid in understanding the mesoscale dynamics underlying cognitive function.

Clinical Utilisation of Wide-Field Optical Coherence Tomography and Angiography: A Narrative Review.

Many important abnormalities of the vitreous, retina and choroid are predominantly located in the peripheral retina. In some retinal diseases with both central and peripheral manifestations, pathological structural or vascular changes can be apparent in the periphery before they are detectable in the central retina. Conventional optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A) imaging only cover the most posterior 30° of the retina. Wide-field OCT (WF-OCT), though offering detailed cross-sectional imaging of the peripheral retina, is not yet systematically used in clinical practice. This narrative review provides a presentation of the utilisation of WF-OCT and WF-OCT-A in the diagnosis and monitoring of a variety of ophthalmological diseases and discusses the advantages and limitations of the technology. With the rapidly developing technology, multiple WF-OCT and WF-OCT-A devices are now commercially available and enable the clinician to obtain scans within a field of view up to 200°. As detailed in this review, several studies have shown promising results in the application of WF-OCT and WF-OCT-A in diseases of the retina, choroid and vitreous, such as retinal vein occlusion, diabetic retinopathy, ocular oncology, paediatric ophthalmology, uveitis and lesions of the vitreo-retinal interface. In conclusion, WF-OCT and WF-OCT-A can reliably produce high-quality, non-invasive images of the vitreous, retinal, and choroidal structures and vascularity covering the posterior pole as well as the mid and far periphery. These methods can be a valuable part of a multimodal imaging approach in the management of a variety of ocular conditions. Future studies are warranted to investigate the patient outcome benefits of implementation of WF-OCT and WF-OCT-A imaging in a real-life clinical setting.

Sex differences in choroidal vessels using novel wide-field choroidal en-face images from optical coherence tomography.

This study aims to develop a method to quantify choroidal vessels in normal eyes using wide-field optical coherence tomography (OCT) en-face images. The study included participants with normal eyes in whom wide-angle OCT images were acquired to generate planarized choroidal en-face and thickness map images. The images were segmented into central, midperipheral, and peripheral areas, and the midperipheral and peripheral areas were further segmented into supratemporal, infratemporal, supranasal, and infranasal sectors. The mean planarized choroidal-vessel density (p-CVD), planarized choroidal-vessel size (p-CVS), and choroidal thickness (CT) were calculated in each sector. Sex differences were analyzed using the Mann-Whitney U test. The study included 162 participants comprising 84 female (mean age, 43.5 years; axial length, 24.0 mm) and 78 male (mean age, 44.4 years; axial length, 24.2 mm) participants with no significant differences in demographics (P ≥ 0.107). Men had a higher mean p-CVD in all regions (P < 0.001). The mean p-CVS was greater in men in all regions except for the supratemporal sector (P < 0.001). No significant differences in sex in the mean CT were observed in all regions (P ≥ 0.106). The p-CVD and p-CVS in normal eyes differ between sexes. This finding may contribute to the understanding of the pathophysiology of choroidal diseases.

Deep Learning for prediction of late recurrence of retinal detachment using preoperative and postoperative ultra-wide field imaging.

PURPOSE: To elaborate a deep learning (DL) model for automatic prediction of late recurrence (LR) of rhegmatogenous retinal detachment (RRD) using pseudocolor and fundus autofluorescence (AF) ultra-wide field (UWF) images obtained preoperatively and postoperatively. MATERIALS AND METHODS: We retrospectively included patients >18 years who underwent either scleral buckling (SB) or pars plana vitrectomy (PPV) for primary or recurrent RRD with a post-operative follow-up >2 years. Records of RRD recurrence between 6 weeks and 2 years after surgery served as a ground truth for the training of the deep learning (DL) models. Four separate DL models were trained to predict LR within the 2 postoperative years (binary outputs) using, respectively, UWF preoperative and postoperative pseudocolor images and UWF preoperative and postoperative AF images. RESULTS: A total of 412 eyes were included in the study (332 eyes treated with PPV and 80 eyes with SB). The mean follow-up was 4.0 ± 2.1 years. The DL models based on preoperative and postoperative pseudocolor UWF imaging predicted recurrence with 85.6% (sensitivity 86.7%, specificity 85.4%) and 90.2% accuracy (sensitivity 87.0%, specificity 90.8%) in PPV-treated eyes, and 87.0% (sensitivity 86.7%, specificity 87.0%) and 91.1% (sensitivity 88.2%, specificity 91.9%) in SB-treated eyes, respectively. The DL models using preoperative and postoperative AF-UWF imaging predicted recurrence with 87.6% (sensitivity 84.0% and specificity 88.3%) and 91.0% (sensitivity 88.9%, specificity 91.5%) accuracy in PPV eyes, and 86.5% (sensitivity 87.5%; specificity 86.2%) and 90.6% (sensitivity 90.0%, specificity 90.7%) in SB eyes, respectively. Among the risk factors detected with visualisation methods, potential novel ones were extensive laser retinopexy and asymmetric staphyloma. CONCLUSIONS: DL can accurately predict the LR of RRD based on UWF images (especially postoperative ones), which can help refine follow-up strategies. Saliency maps might provide further insight into the dynamics of RRD recurrence.

Widefield Retinal Imaging in Gyrate Atrophy: Correlation of Structural, Biochemical, and Functional Characteristics.

OBJECTIVES: To profile a cohort of gyrate atrophy patients classified by widefield retinal imaging and correlate the structural, biochemical, and functional characteristics. DESIGN: Retrospective observational cohort study. PARTICIPANTS: Sixty-five patients (129 eyes) with gyrate atrophy. METHODS: Data of participants with a diagnosis of gyrate atrophy were retrieved from their electronic medical records (January 2015 to December 2023). Retinal involvement was classified into three zones using widefield retinal images. Zone 3 had atrophic patches in the area anterior to the equator; Zone 2 had involvement limited to the arcades but posterior to the equator; Zone 1 had involvement within the vascular arcades and/or peripapillary region, with or without any other zone involvement. Macular assessment was performed using swept-source OCT (n=104). Flash ERG was performed in 40 eyes. serum ornithine levels (n=35) were measured, and genetic analysis was conducted (n=18). MAIN OUTCOME MEASURES: Demography, patient profile, zone of retina involved, macular features, and serum ornithine levels. RESULTS: The average age at presentation was 26.4 (range: 5-67) years, majority were male. Nyctalopia (n=35, 53.8%) and blurred vision (n=29, 44.6%) were the most common symptoms. Positive family history was reported in 32.3% of patients. Most eyes were myopic (69.8%<-3 D). Posterior subcapsular cataracts were documented in 36.4% of eyes. The highest frequency of retinal area affected was Zone 1 (57.14%), followed by Zone 2 (33.33%) and Zone 3 (9.52%), correlating with age at presentation. Foveoschisis was observed in 57.7% of eyes, with a higher prevalence in eyes with Zone 1 disease. Elevated serum ornithine levels (>163 µmol/L) were found in 77.14% of patients. ERG showed non-recordable (n=32) or severely reduced (n=8) responses in scotopic and photopic phases. Genetic analysis of 18 patients identified mutations in the OAT gene, including a novel missense variant (c.290T>C). CONCLUSIONS: This large cohort of patients with gyrate atrophy revealed symmetrical involvement, predominantly in Zone 1. Most patients presented between the first and third decades, experienced nyctalopia, vision reduction, early posterior subcapsular cataracts, and varying degrees of myopia. Zone 1 involvement was strongly associated with foveoschisis and visual compromise.

Retinal vascular morphological characteristics in diabetic retinopathy: an artificial intelligence study using a transfer learning system to analyze ultra-wide field images.

AIM: To investigate the morphological characteristics of retinal vessels in patients with different severity of diabetic retinopathy (DR) and in patients with or without diabetic macular edema (DME). METHODS: The 239 eyes of DR patients and 100 eyes of healthy individuals were recruited for the study. The severity of DR patients was graded as mild, moderate and severe non-proliferative diabetic retinopathy (NPDR) according to the international clinical diabetic retinopathy (ICDR) disease severity scale classification, and retinal vascular morphology was quantitatively analyzed in ultra-wide field images using RU-net and transfer learning methods. The presence of DME was determined by optical coherence tomography (OCT), and differences in vascular morphological characteristics were compared between patients with and without DME. RESULTS: Retinal vessel segmentation using RU-net and transfer learning system had an accuracy of 99% and a Dice metric of 0.76. Compared with the healthy group, the DR group had smaller vessel angles (33.68±3.01 vs 37.78±1.60), smaller fractal dimension (Df) values (1.33±0.05 vs 1.41±0.03), less vessel density (1.12±0.44 vs 2.09±0.36) and fewer vascular branches (206.1±88.8 vs 396.5±91.3), all P<0.001. As the severity of DR increased, Df values decreased, P=0.031. No significant difference between the DME and non-DME groups were observed in vascular morphological characteristics. CONCLUSION: In this study, an artificial intelligence retinal vessel segmentation system is used with 99% accuracy, thus providing with relatively satisfactory performance in the evaluation of quantitative vascular morphology. DR patients have a tendency of vascular occlusion and dropout. The presence of DME does not compromise the integral retinal vascular pattern.

Open-source statistical and data processing tools for wide-field optical imaging data in mice.

Significance: Wide-field optical imaging (WOI) can produce concurrent hemodynamic and cell-specific calcium recordings across the entire cerebral cortex in animal models. There have been multiple studies using WOI to image mouse models with various environmental or genetic manipulations to understand various diseases. Despite the utility of pursuing mouse WOI alongside human functional magnetic resonance imaging (fMRI), and the multitude of analysis toolboxes in the fMRI literature, there is not an available open-source, user-friendly data processing and statistical analysis toolbox for WOI data. Aim: To assemble a MATLAB toolbox for processing WOI data, as described and adapted to combine techniques from multiple WOI groups and fMRI. Approach: We outline our MATLAB toolbox on GitHub with multiple data analysis packages and translate a commonly used statistical approach from the fMRI literature to the WOI data. To illustrate the utility of our MATLAB toolbox, we demonstrate the ability of the processing and analysis framework to detect a well-established deficit in a mouse model of stroke and plot activation areas during an electrical paw stimulus experiment. Results: Our processing toolbox and statistical methods isolate a somatosensory-based deficit 3 days following photothrombotic stroke and cleanly localize sensory stimulus activations. Conclusions: The toolbox presented here details an open-source, user-friendly compilation of WOI processing tools with statistical methods to apply to any biological question investigated with WOI techniques.

Follow-up of retinoblastoma using RetCam fluorescein angiography and correlation with clinical findings.

PURPOSE: To report RetCam fluorescein angiographic (FA) changes and correlation with clinical findings in the follow-up of retinoblastoma (RB) after frontline intravenous chemotherapy and other treatments. METHODS: Patients having RB who underwent post-treatment RetCam fundus photography and FA under general anesthesia between February 2020 and February 2022 were retrospectively analyzed. RESULTS: 78 eyes of 70 patients with RB were included. In 55 (70.5%) eyes with type 1, 2 or 3 regression patterns, the main tumor started to show hyperfluorescence in arterial phase in 24 eyes (43.6%), in early venous phase in 24 (43.6%) eyes, and in late venous phase in 7 (12.7%) eyes. Of thirty-six (46.2%) eyes with chorioretinal scars developing after focal treatments (cryotherapy and transpupillary thermotherapy), window defects and visible choroidal vessels were found in all eyes, scleral staining in 10 (27.8%), and gliosis on scar tissue in 8 (22.2%). Vitreous seeds showed hyperfluorescence if they were calcified (6 eyes, 7.7%) and hypofluorescence if non-calcified (11 eyes, 14.1%). Retrohyaloid seeds (11 eyes, 14.1%) were hypo/isofluorescent while subretinal seeds (6 eyes, 7.7%) were hyperfluorescent. Leakage from peripheral retinal vessels was detected in 14 (17.9%) eyes and non-perfusion in 6 (7.7%) eyes. CONCLUSION: RetCam wide-angle FA is useful to evaluate the tumor and associated vascular and retinal changes after treatment in RB. Regressed tumors demonstrate later fluorescein uptake in venous phases. Fluorescein angiographic changes in chorioretinal scars include window defects, visibility of choroidal vessels, scleral staining, and leakage from vessels. Retinal vascular leakage and peripheral non-perfusion can be seen in eyes with regressed stable tumors.

Convolutional neural network classifies visual stimuli from cortical response recorded with wide-field imaging in mice.

Objective.The optic nerve is a good location for a visual neuroprosthesis. It can be targeted when a subject cannot receive a retinal prosthesis and it is less invasive than a cortical implant. The effectiveness of an electrical neuroprosthesis depends on the combination of the stimulation parameters which must be optimized, and an optimization strategy might be performing closed-loop stimulation using the evoked cortical response as feedback. However, it is necessary to identify target cortical activation patterns and to associate the cortical activity with the visual stimuli present in the visual field of the subjects. Visual stimuli decoding should be performed on large areas of the visual cortex, and with a method as translational as possible to shift the study to human subjects in the future. The aim of this work is to develop an algorithm that meets these requirements and can be leveraged to automatically associate a cortical activation pattern with the visual stimulus that generated it.Approach.Three mice were presented with ten different visual stimuli, and their primary visual cortex response was recorded using wide-field calcium imaging. Our decoding algorithm relies on a convolutional neural network (CNN), trained to classify the visual stimuli from the correspondent wide-field images. Several experiments were performed to identify the best training strategy and investigate the possibility of generalization.Main results.The best classification accuracy was 75.38% ± 4.77%, obtained pre-training the CNN on the MNIST digits dataset and fine-tuning it on our dataset. Generalization was possible pre-training the CNN to classify Mouse 1 dataset and fine-tuning it on Mouse 2 and Mouse 3, with accuracies of 64.14% ± 10.81% and 51.53% ± 6.48% respectively.Significance.The combination of wide-field calcium imaging and CNNs can be used to classify the cortical responses to simple visual stimuli and might be a viable alternative to existing decoding methodologies. It also allows us to consider the cortical activation as reliable feedback in future optic nerve stimulation experiments.

History information emerges in the cortex during learning.

We learn from our experience but the underlying neuronal mechanisms incorporating past information to facilitate learning is relatively unknown. Specifically, which cortical areas encode history-related information and how is this information modulated across learning? To study the relationship between history and learning, we continuously imaged cortex-wide calcium dynamics as mice learn to use their whiskers to discriminate between two different textures. We mainly focused on comparing the same trial type with different trial history, that is, a different preceding trial. We found trial history information in barrel cortex (BC) during stimulus presentation. Importantly, trial history in BC emerged only as the mouse learned the task. Next, we also found learning-dependent trial history information in rostrolateral (RL) association cortex that emerges before stimulus presentation, preceding activity in BC. Trial history was also encoded in other cortical areas and was not related to differences in body movements. Interestingly, a binary classifier could discriminate trial history at the single trial level just as well as current information both in BC and RL. These findings suggest that past experience emerges in the cortex around the time of learning, starting from higher-order association area RL and propagating down (i.e., top-down projection) to lower-order BC where it can be integrated with incoming sensory information. This integration between the past and present may facilitate learning.

Preoperative estimation of retinal hole location using ultra-wide-field imaging.

BACKGROUND/OBJECTIVE: Accurate localization of retinal holes is essential for successful scleral buckling (SB) surgery. We aimed to verify the feasibility of using ultra-wide-field (UWF) imaging for preoperative estimation of retinal hole location. PATIENTS AND METHODS: We observed 21 eyes from 21 patients with rhegmatogenous retinal detachment (RRD) who underwent successful SB. They were treated at the Department of Ophthalmology of the Second Hospital of Hebei Medical University between November 2020 and November 2021. UWF fundus photography using an Optos device was performed at different steering positions 1 day before, 1 day after, and 1 month after SB. Using the preoperative fundus images, we measured the transverse diameter of the optic disc (D1) and the distance from the centre of the retinal holes to the ora serrata (D2). The accurate transverse diameter of the optic disc (Dd) was measured preoperatively using optical coherence tomography. The same surgeon measured the scleral chord lengths intraoperatively from the limbus to the located retinal hole marked on the sclera using an ophthalmic calliper. Statistical software was used to analyze the consistency of scleral chord length between the retinal hole and the limbus, which was estimated by preoperative UWF imaging and was measured using an ophthalmic calliper intraoperatively. RESULTS: There was no statistically significant difference in the scleral chord length between the retinal holes and the limbus, which was estimated by preoperative UWF fundus photography and was measured by the calliper during surgery. CONCLUSION: It is feasible to locate retinal holes using UWF fundus photography before SB, which is helpful for quick localization, thereby reducing the learning curve of SB surgery.

Preoperative ultra-wide-field imaging can provide abundant information about retinal holes and is helpful for assessing their location before surgery.In this prospective cohort study of 21 patients, 25 retinal holes in four quadrants were observed.Axial length and the position of the holes have little impact on preoperative ultra-wide field imaging assessment.

Spotlight on Lattice Degeneration Imaging Techniques.

Lattice degeneration (LD), routinely diagnosed with indirect ophthalmoscopy, is one of the most common and clinically significant peripheral retinal findings. In this review, we have summarized the data on currently available imaging techniques which help to improve diagnosis and our understanding of LD pathogenesis. Ultra-wide field imaging provides reliable color fundus capturing for the primary diagnosis of LD and may also be used as a screening tool. Wide-field imaging can be used for targeted documentation of LD lesions using true colors and with minimal optical distortions. Information on the status of the vitreoretinal interface, including detection of retinal holes, detachments, and vitreous tractions, can be obtained with peripheral structural optical coherence tomography (OCT) or scanning laser ophthalmoscopy in retro-mode. These techniques clarify the associated risks of rhegmatogenous retinal detachment. Fundus autofluorescence can provide details on atrophic changes. However, the risk of retinal detachment by means of this technique requires further investigation. OCT angiography may be successfully performed for some lesions. Taken together, OCT and OCT angiography demonstrate thinning of the choroid, alteration of local choroidal microcirculation, and, in severe lesions, involvement of the sclera. OCT angiography confirms loss of retinal microcirculation within LD lesion, which was previously shown with fluorescein angiography. In conclusion, despite relatively simple primary diagnosis, imaging of LD lesions remains challenging due to their peripheral localization. However, several new strategies, including ultra-wide field imaging, peripheral OCT, and scanning laser ophthalmoscopy, make LD imaging possible on a routine basis, improving diagnosis and understanding of LD pathogenesis.

Wide-field OCT-angiography assessment of choroidal thickness and choriocapillaris in eyes with central serous chorioretinopathy.

Purpose: To assess wide-field changes in choroidal thickness and choriocapillaris in eyes with central serous chorioretinopathy (CSC) compared with the fellow eyes and eyes from healthy individuals using wide-field swept-source (SS) OCT-Angiography (OCTA). Methods: A cross-sectional study in which 68 eyes from 34 individual patients affected by unilateral CSC and 32 eyes of 32 age- and sex-matched healthy subjects were evaluated. All subjects underwent wide-field SS-OCTA examination to quantify choroidal thickness and vascular density of the choriocapillaris. To assess the wide-field changes, we developed five 4-by-4 mm square regions located in the posterior pole and in the four quadrants of the peripheral retina (superotemporal, inferotemporal, superonasal, and inferonasal subfields, respectively). Results: The choroidal thickness of eyes with CSC was greater than that of the fellow eyes in the central and inferonasal subfields (p < 0.001 for the central subfield and p = 0.006 for the inferonasal subfield, respectively). Compared with the choroidal thickness of healthy eyes, that of patients with CSC were significantly greater in all the subfields (p < 0.05 for the fellow eyes and p < 0.05 for eyes with CSC, respectively). Compared with that of healthy eyes, the vascular density of choriocapillaris in eyes of patients with CSC were significantly greater in the central and superotemporal subfields (p < 0.05 for the fellow eyes and p < 0.05 for eyes with CSC, respectively). In the central region, the vascular density of choriocapillaris of the fellow eyes was greater than eyes with CSC (p = 0.023). Conclusion: CSC appears to be a bilateral disease with asymmetric manifestations. Local factors of the diseased eyes may play an important role in the development of CSC, during which dynamic and regional changes in the choriocapillaris may have happened. Wide-field swept-source OCTA provided a useful tool to study the pathogenesis of CSC.

Tilted disc syndrome (TDS): New hypotheses for posterior segment complications and their implications in other retinal diseases.

Tilted disc syndrome (TDS) is considered a congenital anomaly due to a delayed closure of the embryonic fissure. It is characterized by an oblique orientation of the axis of the optic disc, associated with other posterior pole anomalies such as inferior crescent, situs inversus and inferior staphyloma. The aim of this review was to summarize the data supporting the current hypotheses for the pathogenesis of TDS, and its anatomical and functional clinical consequences. Recent imaging techniques, such as magnetic resonance imaging, wide-field fundus imaging, and 2- and 3-D optical coherence tomography have provided a new perspective on TDS and its complications. Different abnormalities have previously been reported, both in the anterior and posterior segments. The focus was on vision-threatening chorioretinal changes or complications, including choroidal neovascularization and serous retinal detachments and their therapeutic options. Based on clinical observations, assumptions were proposed to understand the occurrence of complications such as chorioretinal degenerative changes, choroidal neovascularization and polypoidal choroidal vasculopathy, macular serous retinal detachment, myopic foveoschisis and chorioretinal folds. These hypotheses could be referred to as the curvature "breaking point" hypothesis, the uneven growth "tractional" hypothesis, the "container-content" imbalance hypothesis, and the "choroidal funnel" hypothesis. Because these complications could also occur in other contexts, understanding the pathogenesis of TDS complications could help to understand their pathophysiology.