Luminance Changes Research Articles

Optical imaging of the intrinsic signal as a tool to characterize orientation sensitivity in the primary visual cortex of the young mouse.

We employed intrinsic signal optical imaging (ISOI) to investigate orientation sensitivity bias in the visual cortex of young mice. Optical signals were recorded in response to the moving light gratings stimulating ipsi‑, contra‑ and binocular eye inputs. ISOI allowed visualization of cortical areas activated by gratings of specific orientation and temporal changes of light scatter during visual stimulation. These results confirmed ISOI as a reliable technique for imaging the activity of large populations of neurons in the mouse visual cortex. Our results revealed that the contralateral ocular input activated a larger area of the primary visual cortex than the ipsilateral input, and caused the highest response amplitudes of light scatter signals to all ocular inputs. Horizontal gratings moved in vertical orientation induced the most significant changes in light scatter when presented contralaterally and binocularly, surpassing stimulations by vertical or oblique gratings. These observations suggest dedicated integration mechanisms for the combined inputs from both eyes. We also explored the relationship between point luminance change (PLC) of grating stimuli and ISOI time courses under various orientations of movements of the gratings and ocular inputs, finding higher cross-correlation values for cardinal orientations and ipsilateral inputs. These findings suggested specific activation of different neuronal assemblies within the mouse's primary visual cortex by grating stimuli of the corresponding orientation. However, further investigations are needed to examine this summation hypothesis. Our study highlights the potential of optical imaging as a valuable tool for exploring functional‑anatomical relationships in the mouse visual system.

Mechanofluorochromic Properties of 1,4-Diphenylanthracene Derivatives with Hypsochromic Shift.

Several types of 1,4-diphenylanthracene derivatives 1-4 were prepared, and their photophysical properties were observed in the solid and solution states. Interestingly, the CN-group-substituted 1,4-diphenylanthracene derivative 2 was found to exhibit a higher fluorescence quantum yield (ϕf = 0.71) in the solid state than in the solution state, probably due to the formation of an intermolecular Ar-CN⋯H-Ar hydrogen bond and antiparallel type locked packing structure in the solid state. Furthermore, for some derivatives, an increase in the fluorescence quantum yield was observed in the PMMA film (1 wt%) over both the solid state and the solution state. More interestingly, some of the 1,4-diphenylanthracene derivatives exhibited unusual mechanofluorochromic properties with a "hypsochromic shift" in luminous color depending on the substituents of the phenyl group, and with the derivatives having CF3, OMe, CN, and two F substituents (1d-1f, 2-4) showing a significant luminous color change with a "hypsochromic shift" after grinding. However, no change in the luminous color was observed for the derivatives having H, Me, and one F substituent (1a-1c), and especially for some of the CN-substituted derivatives, a reversible luminous color change with a "hypsochromic shift" was observed, probably due to the formation of an antiparallel type packing structure. These "hypsochromic" anthracene derivatives could probably be utilized as new mechanofluorochromic materials.

Decoupling of the pupillary light response during internal attention: The modulating effect of luminance intensity

In a world full of sensory stimuli, attention guides us between the external environment and our internal thoughts. While external attention involves processing sensory stimuli, internal attention is devoted to self-generated representations such as planning or spontaneous mind wandering. They both draw from common cognitive resources, thus simultaneous engagement in both often leads to interference between processes. In order to maintain internal focus, an attentional mechanism known as perceptual decoupling takes effect. This mechanism supports internal cognition by decoupling attention from the perception of sensory information. Two previous studies of our lab investigated to what extent perceptual decoupling is evident in voluntary eye movements. Findings showed that the effect is mediated by the internal task modality and workload (visuospatial > arithmetic and high > low, respectively). However, it remains unclear whether it extends to involuntary eye behavior, which may not share cognitive resources with internal activities. Therefore, the present experiment aimed to further elucidate attentional dynamics by examining whether internal attention affects the pupillary light response (PLR). Specifically, we consistently observed that workload and task modality of the internal task reduced the PLR to luminance changes of medium intensity. However, the PLR to strong luminance changes was less or not at all affected by the internal task. These results suggest that perceptual decoupling effects may be less consistent in involuntary eye behavior, particularly in the context of a salient visual stimulus.

Metal selectivity and translocation mechanism characterization in proteoliposomes of the transmembrane NiCoT transporter NixA from Helicobacter pylori.

Essential trace metals play key roles in the survival, replication, and virulence of bacterial pathogens. Helicobacter pylori (H. pylori), the main bacterial cause of gastric ulcers, requires Ni(ii) to colonize and persist in the acidic environment inside the stomach, exploiting the nickel-containing enzyme urease to catalyze the hydrolysis of urea to ammonia and bicarbonate and create a pH-buffered microenvironment. Urease utilizes Ni(ii) as a catalytic cofactor for its activity. In ureolytic bacteria, unique transmembrane (TM) transporters evolved to guarantee the selective uptake and efflux of Ni(ii) across cellular membranes to meet the cellular requirements. NixA is an essential Ni(ii) transporter expressed by H. pylori when the extracellular environment experiences a drop in pH. This Class I nickel-cobalt transporter of the NiCoT family catalyzes the uptake of Ni(ii) across the inner membrane from the periplasm. In this study, we characterized NixA using a platform whereby, for the first time on a NiCoT transporter, recombinantly expressed and purified NixA and key mutants in the translocation pathway have been reconstituted in artificial lipid bilayer vesicles (proteoliposomes). Fluorescent sensors responsive to Ni(ii) transport (Fluozin-3-Zn(ii)), luminal pH changes (pyranine), and membrane potential (oxonol VI) were encapsulated in the proteoliposomes lumen to monitor, in real-time, NixA transport properties and translocation mechanism. Kinetic transport analysis revealed that NixA is highly selective for Ni(ii) with no substrate promiscuity towards Co(ii), the other putative metal substrate of the NiCoT family, nor Zn(ii). NixA-mediated Ni(ii) transport exhibited a Michaelis-Menten-type saturable substrate concentration dependence, with an experimental KM, Ni(ii) = 31.0 ± 1.2 μM. Ni(ii) transport by NixA was demonstrated to be electrogenic, and metal translocation did not require a proton motive force, resulting in the generation of a positive-inside transmembrane potential in the proteoliposome lumen. Mutation analysis characterized key transmembrane residues for substrate recognition, binding, and/or transport, suggesting the presence of a three-step transmembrane translocation conduit. Taken together, these investigations reveal that NixA is a Ni(ii)-selective Class I NiCoT electrogenic uniporter. The work also provides an in vitro approach to characterize the transport properties of metal transporters responsible for Ni(ii) acquisition and extrusion in prokaryotes.

Behavioral photosensitivity of multi-color-blind medaka: enhanced response under ultraviolet light in the absence of short-wavelength-sensitive opsins

BackgroundThe behavioral photosensitivity of animals could be quantified via the optomotor response (OMR), for example, and the luminous efficiency function (the range of visible light) should largely rely on the repertoire and expression of light-absorbing proteins in the retina, i.e., the opsins. In fact, the OMR under red light was suppressed in medaka lacking the red (long-wavelength sensitive [LWS]) opsin.ResultsWe investigated the ultraviolet (UV)- or blue-light sensitivity of medaka lacking the violet (short-wavelength sensitive 1 [SWS1]) and blue (SWS2) opsins. The sws1/sws2 double or sws1/sws2/lws triple mutants were as viable as the wild type. The remaining green (rhodopsin 2 [RH2]) or red opsins were not upregulated. Interestingly, the OMR of the double or triple mutants was equivalent or even increased under UV or blue light (λ = 350, 365, or 450 nm), which demonstrated that the rotating stripes (i.e., changes in luminance) could fully be recognized under UV light using RH2 alone. The OMR test using dichromatic stripes projected onto an RGB display consistently showed that the presence or absence of SWS1 and SWS2 did not affect the equiluminant conditions.ConclusionsRH2 and LWS, but not SWS1 and SWS2, should predominantly contribute to the postreceptoral processes leading to the OMR or, possibly, to luminance detection in general, as the medium-wavelength-sensitive and LWS cones, but not the SWS cones, are responsible for luminance detection in humans.

Anti‐Counterfeiting Application of Persistent Luminescence Materials and Its Research Progress

AbstractPersistent luminescent materials can continue to emit light after stopping excitation, and their stored energy is gradually released during the decay time after persistent emitting, which makes the color and luminance changes in slow decay and plays an important role in protecting information and combating forgery. When combined with other anti‐counterfeiting technologies to form a multi‐modal and multi‐process anti‐counterfeiting design, it perfectly hides the real information and has a broad application prospect in anti‐counterfeiting logo design. A brief overview of the design of three different persistent luminescence‐based anti‐counterfeiting applications in unimodality to achieve information encryption in the time dimension. The energy stored in the trap is studied to be released by different physical stimuli and applied to stimulus‐like responsive persistent luminescent materials, and the design of persistent luminescence anti‐counterfeiting applications based on many different processes in dual‐modality, obtaining the dynamic anti‐counterfeiting effect of multiple processes in multiple modes. This work reviews the research background of persistent luminescent materials in the field of anti‐counterfeiting in recent years, compares the important breakthrough progress of persistent luminescent materials applied to anti‐counterfeiting research, and finally puts forward the current problems, future challenges, and development directions.

Open-DPSM: An open-source toolkit for modeling pupil size changes to dynamic visual inputs

Pupil size change is a widely adopted, sensitive indicator for sensory and cognitive processes. However, the interpretation of these changes is complicated by the influence of multiple low-level effects, such as brightness or contrast changes, posing challenges to applying pupillometry outside of extremely controlled settings. Building on and extending previous models, we here introduce Open Dynamic Pupil Size Modeling (Open-DPSM), an open-source toolkit to model pupil size changes to dynamically changing visual inputs using a convolution approach. Open-DPSM incorporates three key steps: (1) Modeling pupillary responses to both luminance and contrast changes; (2) Weighing of the distinct contributions of visual events across the visual field on pupil size change; and (3) Incorporating gaze-contingent visual event extraction and modeling. These steps improve the prediction of pupil size changes beyond the here-evaluated benchmarks. Open-DPSM provides Python functions, as well as a graphical user interface (GUI), enabling the extension of its applications to versatile scenarios and adaptations to individualized needs. By obtaining a predicted pupil trace using video and eye-tracking data, users can mitigate the effects of low-level features by subtracting the predicted trace or assess the efficacy of the low-level feature manipulations a priori by comparing estimated traces across conditions.

Thermally Reversible Luminescence in Ferroelastic Phase Transition Materials

AbstractThe thermally reversible luminescent materials with information encryption are important and widely used in the information age. However, it is challenging to obtain such materials. In this work, a 0D In‐based hybrid compound [(CH3)3NCH2CHCH2]2InCl5 ((TAMAC)2InCl5) is synthesized and undergoes a high‐temperature ferroelastic phase transition with an Aizu notation of mmF2/m at 333 K. In the room temperature phase (RTP), it shows a weak blue glow with a photoluminescent quantum yield (PLQY) of 0.32% under the UV lamp at 365 nm. By using a metal ion doping strategy to improve the photophysical properties, a series of compounds is obtained: (TAMAC)2In1‐xCl5:xSb3+ (x = 0.1%,0.5%,1%, and 1.5%, x represents the actual amount) with the same ferroelastic phase transition as that found in (TAMAC)2InCl5. When x = 0.5%, the PLQY reaches 50.66% with the luminous color change from blue to orange. Interestingly, it is found that the orange luminescence of the doped materials can rapidly and reversibly quench and recover between heating and cooling cycles, where the thermally induced phase transition results in this thermally reversible luminescence phenomenon. This discovery reveals the mechanism of luminescence quenching and phase transition, and provides a new pathway for the construction of new thermal‐sensitive luminescent materials with information encryption.

Poster Session II: Luminance and chromaticity discrimination sensitivities following a sudden decrease in background luminance.

When we enter a dark place like a tunnel from a bright exterior, our visual sensitivities take some time to adapt to the lower light level. However, there have been few reports about how quickly our sensitivities of luminance and chromaticity discrimination recover in this situation. This study aimed to quantify the time course of discrimination sensitivity for luminance and chromaticity directions after an abrupt decrease in background luminance. In each trial, the background luminance dropped from 100 cd/m² to 1 cd/m². Then, one target and three reference stimuli with different colors were presented under four stimulus onset asynchrony (SOA) conditions. The observer was asked to discriminate the target stimulus from the reference stimuli. The results showed that discrimination sensitivity was lowest right after the background luminance change and gradually improved with SOAs. However, sensitivity recovery differed across color directions, with the most improvement in luminance, followed by S, and negligible change in L-M. There was a statistically significant difference between +S and ±(L-M) sensitivities, indicating that the sensitivity recovery after the sudden background luminance change differed between chromaticity directions. Based on the comparison with previous studies, we speculate that both adaptation and masking may contribute to the temporal change of discrimination sensitivities.

Impact of prandial state on luminal and permeation-behavior of fosamprenavir oral suspension studied by in vitro tools: Solubility-, bioconversion- and permeation- studies in biomimetic media

Fosamprenavir is a prodrug designed to overcome the solubility challenge of the parent drug amprenavir, a protease inhibitor. For the marketed oral suspension (Telzir®) a clinically documented negative food effect has been reported.The present study aims to gain a better mechanistic understanding of the food effect by in vitro tests on solubility, bioconversion, permeability, and dynamic dissolution/bioconversion/permeation studies in a high throughput manner on a microtiter plate (Permeapad® Plate). In order to mimick luminal condition changes in connection with food, various modified versions of fasted and fed state simulated intestinal fluids (FaSSIF-V2) and (FeSSIF–V2) were used. The kinetics of enzymatic cleavage (simulated bioconversion) were studied in these media with a focus on molecularly dissolved drug concentrations using microdialysis. Dynamic dissolution/bioconversion/permeation experiments, indicated the following factors to contribute to reduced permeation in fed state: elevated inorganic phosphate concentrations, higher concentrations of bile salts and lipids and lower intestinal pH. The impact of these effects is difficult to capture in vivo due to their interconnection and large variability between individuals.This study revealed factors leading to an altered luminal behavior of Telzir® oral suspension in fed state, which may contribute to explain the observed reduced amprenavir absorption from the suspension. Especially the high throughput small-scale dissolution/bioconversion/permeation experiments on a microtiter plate were demonstrated an efficient and powerful tool for elucidating the food effects of phosphate-ester prodrug type drug products as far as their altered luminal behavior is concerned.

Histopathological Validation of Microvascular Anastomosis using Two-Throw Reef Knots - An Experimental Study.

Knot configuration is an important but relatively neglected topic in microvascular anastomosis literature. To study the differences between end-to-end microvascular anastomosis performed with two-throw reef knots as compared to traditional three-throw knots in a rat femoral artery model at the histological level. Sprague Dawley rats underwent end-to-end microvascular anastomosis of the right femoral artery (one-way-up method). The rats were divided into two groups: two-throw reef knots versus traditional three-throw knots. The patency was checked by the standard empty refill method. After 2 weeks, the rats underwent re-exploration. An anastomotic segment was sent for histological analysis. Histological alterations including luminal patency and changes in Tunica intima, Tunica media, and Tunica adventitia were compared between the two groups. Twenty-nine rats were operated on by the senior author (17 by three-throw and 12 by two-throw reef knots). In the two-throw reef knot group versus the traditional three-throw knot group, the immediate patency rates were 100% versus 82.4%, and the delayed patency rates were 90.9% versus 62.5%, respectively. The histopathological patency rates were concordant with delayed patency rates. Subintimal proliferation and fibrosis were comparable in both groups. Adventitial granulomas were noted in all, irrespective of the knotting technique. Tunica media preservation rates for the two-throw reef knot versus the traditional three-throw knot group were 63.6% versus 0%. Five rats were operated by the beginner in the field, all by two-throw reef knots (to assess the safety of this new method in the hands of a beginner). Microvascular anastomosis performed with two-throw reef knots appears not only feasible but better in terms of anastomosis patency. Histological superiority in terms of Tunica media preservation further validates the technique.

Mechanofluorochromic properties of 1-phenylanthracene derivatives with extremely simple structures

Several types of 1-phenylanthracene derivatives 1–4 were prepared and their photophysical properties were observed in the solution and solid states. Interestingly, the fluorine-substituted 1-phenylanthracene derivative 1c was found to exhibit a higher fluorescence quantum yield (Φf=0.57) in the solid state than in the solution state, probably due to the formation of intermolecular Ar–F•••H–Ar hydrogen bonds. Additionally, some of the 1-phenylanthracene derivatives exhibited mechanofluorochromic properties depending on the substituents of the phenyl group, with the derivatives having CF3, OMe, and CN substituents (1d-1f, 2, 3) showing a significant change in luminous color from a bluish to greenish color at “room temperature” after grinding. However, no change in the luminous color was observed for the derivatives having H, Me, and F substituents (1a-1c) at “room temperature” but luminous color change was observed with low temperature grinding (−78 °C), especially for the CN substituent, in which a significant change in the luminous color was observed at “room temperature” probably due to the formation of Ar-CN•••H–Ar hydorogen bond interactions. Interestingly, for the 1-phenylanthracene derivative 3 substituted with two CN groups, which exhibited a solvatochromic phenomenon, the luminous color recovered with controllable rate from green to bluish when heated and fumed with solvent vapor in the solid state, and the luminous color change with controllable recovery rate was repeatedly successfully observed. These anthracene derivatives have extremely simple structures and could probably be applied as new mechanofluorochromic materials.

TCT-724 Serial Optical Coherence Tomography Assessment of Coronary Artery Luminal Changes in Nontarget Lesions Distally to Percutaneous Coronary Intervention Lesions

TCT-724 Serial Optical Coherence Tomography Assessment of Coronary Artery Luminal Changes in Nontarget Lesions Distally to Percutaneous Coronary Intervention Lesions

Lower Extremity Venous Stent Morphology and Luminal Changes

Lower Extremity Venous Stent Morphology and Luminal Changes

Luminal Changes in Patients with Inferior Vena Cava Filters and Development of Chronic Venous Disease

This study aimed to analyze the luminal changes in the iliocaval veins and their effects on the development of signs and symptoms of chronic venous disease manifesting from inferior vena cava (IVC) filter placement. This was a retrospective observations study; deidentified patients with an IVC filter placed with subsequent luminal changes were included. All patients had a computerized tomography (CT) scan with or without ultrasound and those who underwent an intervention for the obstruction had also venography and intravascular ultrasound (IVUS). The diameter of IVC and iliac veins was measured from the near wall to the far wall. IVC diameters measured less than 12mm were considered to be retractions. Signs and symptoms of chronic venous disease were obtained from patient charts and were reported according to the highest CEAP class. The data were analyzed using descriptive statistics, presenting diameter changes as a mean with standard deviation and a range of diameters included. Overall, 76 patients were included in this study, of whom 66 had occlusion of the IVC or the Iliac veins. Luminal changes of the IVC were observed in all patients. A total of 58 patients presented with chronic post-thrombotic changes in both the IVC and iliac veins. There were 4 patients that had a luminal reduction with no filling defects or post-thrombotic changes. Average IVC diameter and iliac vein diameter was measured to be 8.3±1.4mm and 4.6±1.4mm, respectively. Patients most frequently presented with extremity swelling, but other signs such as venous ulceration or skin damage were observed. Permanent luminal changes of the IVC and iliac veins were observed as a result of IVC filter placement and such patients commonly present with signs and symptoms of chronic venous disease. Together, with other known filter complications, these observations add more reasons for a timely retrieval. When such changes occur, patients' appropriate symptoms can be successfully treated. The permanent changes made by filter placement in the IVC and iliac veins further support filter retrieval in a timely fashion. The luminal changes induced by filter placement should be recognized early, particularly in symptomatic patients who can be safely treated with endovenous procedures.

What role does the submucosa play in the pathophysiology and treatment of achalasia? An analysis of impedance planimetry during POEM.

It is thought the therapeutic benefit of per-oral endoscopic myotomy (POEM) in the treatment of esophageal dysmotility disorders is from longitudinal myotomy creation, but it is unknown if the submucosa contributes to the pathophysiology. This study investigates if submucosal tunnel (SMT) dissection alone contributes to POEM's luminal changes as measured by EndoFLIP. A single-center, retrospective review of consecutive POEM cases from June 1, 2011 to September 1, 2022 with intraoperative luminal diameter and distensibility index (DI) data as measured by EndoFLIP. Patients with diagnoses of achalasia or esophagogastric junction outflow obstruction were grouped by those with pre-SMT and post-myotomy measurements (Group 1) and those with a third measurement post-SMT dissection (Group 2). Outcomes and EndoFLIP data were analyzed using descriptive and univariate statistics. There were 66 patients identified, of whom 57 (86.4%) had achalasia, 32 (48.5%) were female, and median pre-POEM Eckardt score was 7 [IQR: 6-9]. There were 42 (64%) patients in Group 1, and 24 (36%) patients in Group 2, with no differences in baseline characteristics. In Group 2, SMT dissection changed luminal diameter by 2.15 [IQR: 1.75-3.28]cm, which comprised 38% of the median 5.6 [IQR: 4.25-6.3]cm diameter of complete POEM change. Similarly, the median post-SMT change in DI of 1 [IQR: 0.5-1.2]units comprised 30% of the median 3.35 [2.4-3.98]units overall change in DI. Post-SMT diameters and DI were both significantly lower than the full POEM. Esophageal diameter and DI are significantly affected by SMT dissection alone, though not equaling the magnitude of diameter or DI changes from full POEM. This suggests that the submucosa does play a role in achalasia, presenting a future target for refining POEM and developing alternative treatment strategies.

A fractional-order visual neural model for small target motion detection

Detecting small moving targets consisting of one or few pixels is technically demanding due to their limited visual features. Motivated by nature, some bio-inspired models have been developed that simulate the behavior of small target motion detectors (STMDs), a class of specialized neurons found in insects’ visual neural systems dominating in detecting small moving targets during activities such as predation or courtship. However, the existing models’ high dependence on the sampling frequency of input videos becomes a bottleneck that seriously hinders their real-time applications in the physical world. This is because massive computational power is required to capture and process high-sampling-frequency videos. While model detection performance in low-sampling-frequency videos is plagued by significant spatial errors and weak responses. To address these issues, we propose an STMD-based visual neural model with a fractional-order difference operator for small target motion detection. The fractional-order operator captures instantaneous luminance change and integrates it with memory information, where the instantaneous information dominates the integrated signal. The STMD network further separates the rising and falling luminance components, which are aligned in the time domain and then multiplied to predict the location of moving small targets. Due to the rapid response of instantaneous information and the supplement of memory information, the proposed model locates the small moving targets accurately and robustly in low-sampling-frequencies. Numerical experiments show that the proposed model significantly improves the detection performance for low-sampling-frequency videos.

An improved deep learning approach for localization and recognition of plant leaf diseases

A nation's economic progress is significantly influenced by its percentage of crop yields. However, the major barrier to the quantity and quality of yield is crop disease. For quick and reliable recognition of various plant illnesses, it is mandatory to design a computer-aided system. Timely and accurate recognition of numerous crop leaf infections is a complicated job because of the presence of vast sample distortions like the prevalence of clutter, blur, texture, and luminance changes in samples. Moreover, the extreme resemblance between the normal and infected parts of visual samples also extends the difficulty of the identification procedure. Further, the massive differences in the size, structure, and orientation of crop leaves and infected areas also hinder the accurate recognition of various crop diseases. To deal with the listed issues, we have proposed an improved and effective deep-learning strategy namely the PlantRefineDet. Our approach comprises three steps. First, the sample annotations are created for defining the target object. Next, an improved RefineDet approach is presented that employs the ResNet-50 as its base network for extracting a set of deep features. Lastly, the one-step detector RefineDet is utilized to localize and classify numerous crop disorders. The PlantRefineDet approach improves the plant disease localization and categorization results because of its improved feature calculation ability which facilitates the reemployment of features from the previous layers and increases the recall power of the system. Also, the PlantRefineDet approach adopts an additional phase to eliminate the irrelevant anchors and better adjust the bounding box orientation to exactly locate the infected regions of plant leaves which result to improve the recognition performance of the introduced model. We have confirmed the effectiveness of our approach through extensive evaluation on a challenging PlantVillage data sample and obtained a remarkable accuracy of 99.994%.

Multifaceted luminance gain control beyond photoreceptors in Drosophila

Animals navigating in natural environments must handle vast changes in their sensory input. Visual systems, for example, handle changes in luminance at many timescales, from slow changes across the day to rapid changes during active behavior. To maintain luminance-invariant perception, visual systems must adapt their sensitivity to changing luminance at different timescales. We demonstrate that luminance gain control in photoreceptors alone is insufficient to explain luminance invariance at both fast and slow timescales and reveal the algorithms that adjust gain past photoreceptors in the fly eye. We combined imaging and behavioral experiments with computational modeling to show that downstream of photoreceptors, circuitry taking input from the single luminance-sensitive neuron type L3 implements gain control at fast and slow timescales. This computation is bidirectional in that it prevents the underestimation of contrasts in low luminance and overestimation in high luminance. An algorithmic model disentangles these multifaceted contributions and shows that the bidirectional gain control occurs at both timescales. The model implements a nonlinear interaction of luminance and contrast to achieve gain correction at fast timescales and a dark-sensitive channel to improve the detection of dim stimuli at slow timescales. Together, our work demonstrates how a single neuronal channel performs diverse computations to implement gain control at multiple timescales that are together important for navigation in natural environments.

Luminal Changes Seen in the IVC and Iliac Veins, as Well as Signs Demonstrated in a Cohort of Patients With IVC Filter Placement

Luminal Changes Seen in the IVC and Iliac Veins, as Well as Signs Demonstrated in a Cohort of Patients With IVC Filter Placement