Decrease In Luminance Research Articles

Enhancement of organic magnetoresistance by electrical conditioning

We demonstrate that electrical conditioning can be used as an efficient method to enhance the organic magnetoresistance effect in organic light emitting diodes. Depending on duration and intensity of the conditioning process the absolute value of the magnetoresistance effect can be increased from ∼1% to values exceeding 15% at 40mT in devices based on poly(paraphenylene vinylene). Qualitatively, the increase in magnetoresistance can be correlated with a decrease in luminance during the conditioning process. From this we conclude that device degradation mechanisms are responsible for the enhancement of organic magnetoresistance.

An insitu colorimetric measurement study of electrochromism in the di-n-heptyl viologen system

An insitu colorimetric method, based on the CIE (Commission Internationale de l’Eclairage) system of colorimetry, has been applied to the study of the electrochromic N,N′-bis(n-heptyl)-4,4′-bipyridylium (di-n-heptyl viologen) system in aqueous solution on transmissive ITO/glass substrates. On electrochemical reduction of the di-n-heptyl viologen di-cation, the purple di-n-heptyl viologen radical cation salt deposits as a film and the changes in hue and saturation have been tracked using CIE 1931 xy chromaticity coordinates. The CIELAB 1976 colour space coordinates of the purple di-n-heptyl viologen radical cation salt were L∗=76, a∗=33, and b∗=−20, with a complementary wavelength of 548nm. A sharp decrease in luminance was found on formation of the di-n-heptyl viologen radical cation salt. Colour coordinates for the reverse (oxidation) direction plots show hysteresis, implying that specific choice of colour values depends on both the potential applied and from which direction the potential is changed.

Catching the sources of organic LED degradation in action

Though great improvements have been made in recent years, organic light emitting diodes (OLEDs) still have limited lifetimes. In general, the degradation of OLEDs manifests itself as a decrease in device luminance with time. Three distinct modes of deterioration have been recognized: dark spot generation, catastrophic failure, and intrinsic degradation.1 In the first mode, nonemissive regions appear on the emitting surface. Catastrophic failure occurs when electrical shorts cause large leakage currents. In the third mode, changes in the organic material properties cause long-term decreases in the emissive area brightness. So far, methods for investigating these phenomena have involved chemical and physical techniques, like high-performance liquid chromatography and nuclear magnetic resonance.2 These methods typically destroy the device under investigation in order to extract the byproducts of the degradation. Often, using solvents to extract each chemical specie for analysis requires chemical modification. Using synchrotron radiation-based surface techniques, we have developed a new way to investigate dark spot formation. This approach can be applied to any multilayered structures, such as OLEDs. This analysis method enables physical and chemical investigations of real devices, in some cases, even when they are operating. Moreover, synchrotrons offer surfacesensitive techniques to characterize the topmost molecules, without damaging the underlying layers. We applied a typical surface science approach to determine the properties of a thin-film multilayer structure, similar to a small molecule-based OLED. Because it is possible to tune the impinging beam photon energy on the sample, synchrotron radiation can increase the chemical sensitivity of techniques like x-ray photoemission spectroscopy, x-ray absorption nearedge spectroscopy, x-ray transmission, and x-ray fluorescence. Figure 1. This 64×64μm indium photoemission map captures OLED degradation in action. The central bright spot reveals the complete removal of the organic layers. Movement of indium from substrate to cathode causes the higher intensity near the crater.

Optical Characteristics of BaMgAl10O17:Eu2+ Phosphors Coated with SiO2 Nano Film by Using a Radio Frequency Sputtering Method

In this experiment, BaMgAl10O17:Eu2+ (BAM) phosphors were coated with thin SiO2 film by using a radio frequency (RF) sputtering method and investigated their electro-optical properties. It was revealed that the phothluminance properties of BAM phosphors coated with 2 nm SiO2 film were improved, when compared with non-coated ones and more thickly coated ones. The improvement may be due to the increase of an effective excitation transmitted into the BAM phosphors and the increased vacuum ultraviolet (VUV) absorption of the phosphors via SiO2. And the decrease in luminance seen in the thickly coated phosphors may be due to the interruption of the thick SiO2 film in the penetration of VUV. From the results of the experiment, we find that a proper coating of BAM phosphors with thin SiO2 film is a good way for improving the luminance.

Review on electron stimulated surface chemical reaction mechanism for phosphor degradation

Standard cathodoluminescent phosphors normally lose brightness upon bombardment with electron beams. A combination of techniques such as x-ray photoelectron spectroscopy, Auger electron spectroscopy, and cathodoluminescence (CL) spectroscopy was used to show that the main reason for the degradation in CL intensity is the formation of a nonluminescent “dead layer” on the surface due to an electron stimulated surface chemical reaction. The decrease in luminance was found to be a result of the growth of the dead layer. Different phosphors which include sulfide-based as well as oxide-based phosphors reacted similarly under electron bombardment. When ZnS phosphor powder was exposed to the electron beam in a water-rich O2 ambient, a chemically limited ZnO layer was formed on the surface. A layer of ZnSO4 was formed on the surface during the electron beam degradation of the ZnS phosphor powder in a dry O2 ambient. The electron stimulated reaction led to the formation of a luminescent SiO2 layer on the surface of...

The improvement of thermal stability of BaMgAl10O17:Eu2+ coated with MgO

The BaMgAl10O17:Eu2+ (BAM) as an efficient blue-emission phosphor has been used in tricolor fluorescent lamps (FLs) and plasma display panels (PDPs) because it has a deep blue color and a short decay time, but in the process of FL manufacturing, BAM, which spreads on the insides of a glass tub, is heated at 700–750 °C in air. The PDP manufacturing process also heats phosphor at 500–600 °C to make phosphor layers. These heat-treatments result in the luminance decrease. In this work, the BAM phosphors are covered with uniform and continuous MgO coatings via a precipitation route, which is expected to inhibit their surface oxidation. The results indicated that thermal stability was largely improved.

Accuracy of 64-Slice Computed Tomography for the Preoperative Detection of Coronary Artery Disease in Patients With Chronic Aortic Regurgitation

We studied the diagnostic accuracy of 64-slice computed tomography for the diagnosis of significant coronary artery disease (CAD) compared with conventional coronary angiography (CA) in patients with chronic aortic regurgitation (AR) referred for elective aortic valve surgery. Fifty consecutive patients with chronic AR (38 men, mean age 54 +/- 14 years) scheduled for valve surgery underwent 64-slice computed tomographic (CT) coronary angiography and CA. Significant stenosis was defined as a luminal diameter decrease >50%. Mean heart rate during CT scanning was 65.5 +/- 7.4 beats/min. Mean Agatston score was 136 +/- 278 (range 0 to 1207); prevalence of significant CAD in the study population was 26% (13 of 50 patients). Thirteen of 742 segments (1.8%) in 3 patients were considered nondiagnostic with computed tomography because of motion artifacts (n = 9) or calcium (n = 4). In a patient-based analysis taking nonevaluative segments as falsely positive, sensitivity, specificity, and positive and negative predictive values of computed tomography were 100%, 95%, 87%, and 100%, respectively. Preoperative CA could have been avoided in 70% of patients (35 of 50), CA would have been performed to confirm the CT diagnosis in 26% (13 of 50), and unnecessary CA would have been performed in 4% (2 of 50) on the basis of false-positive CT ratings. In conclusion, 64-slice CT coronary angiography provides high diagnostic accuracy for diagnosing significant CAD in patients with chronic AR and may be used as a filter test before valve surgery to decide whether CA should be performed.

Quantitative Analyses of Vitrified Autologous Venous Arterial Bypass Graft Explants

The purpose of this study was to compare vitrified small diameter venous arterial bypass graft explants with fresh graft controls using quantitative morphometrics and smooth muscle physiology. Fresh and vitrified reversed ipsilateral external jugular veins were used as autologous common carotid interposition bypass grafts on the right side in New Zealand White rabbits. Animals were sacrificed at either 2 or 4 weeks after implantation, and the vein grafts were harvested for study. Histology revealed that the vitrified grafts initially arteriolized more slowly than untreated grafts and that they caught up by 4 weeks postimplantation. Histomorphometrics revealed that the intimal area was less in vitrified grafts at 2 weeks (p = 0.007) and that the luminal area was less in vitrified grafts at 4 weeks (p = 0.002). All other morphometric parameters were not significantly different. Smooth muscle physiology demonstrated a tendency for the responses of vitrified grafts to be lower than controls, not statistically significantly different to controls for three of the four contractile agonists at each time point or for relaxation induced by acetycholine. Sodium nitroprusside-induced relaxations appeared to be identical. Sensitivity to histamine was decreased at 2 weeks, and the sensitivity to norepinephrine was increased at 4 weeks in vitrified explants (<0.05). This study demonstrates that vitrification slows down the arterialization process; however, by the end of the month after implantation the vein grafts have similar smooth muscle functions and histology. The greatest concern regarding use of this method for preservation of blood vessels for clinical application was the statistically significant decrease in luminal area observed at 1 month. Longer term in vivo studies are required to determine whether or not the observed luminal decrease progresses to occlusion.

Offsets and prioritizing the selection of new elements in search displays: More evidence for attentional capture in the preview effect

The preview effect refers to the finding that new elements in a search display are prioritized over old elements. Donk and Theeuwes (2001) suggest that this prioritization is due to bottom-up attentional capture, as new elements that abruptly appear with increases in luminance produce a preview effect whereas new elements that are equiluminant to the background do not. The present study extends this research by examining if new elements that appear from offsets, with and without luminance changes, yield similar findings to onsets. This was indeed the case, as equiluminant offsets did not produce a preview effect but offsets with corresponding increases or decreases in luminance did show the prioritization of new elements over old elements. These findings show that the prioritization of new elements is sensitive to changes in luminance but not to the direction of such changes.

Temperature-Dependent Dynamic Behaviors of Organic Light-Emitting Diode

A systematic investigation of temperature-dependent dynamic behaviors of NPD-Alq <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> organic light-emitting diodes (OLEDs) is carried out. Through an in-depth numerical analysis, it has been found that the luminance decreases and consequently the turn-on voltage increases with decreasing temperature due to a reduction of thermally activated hopping speed, which retards the rise of electroluminescence (EL) upon turn-on as well as the discharge upon turn-off of OLEDs. Most importantly, however, the device efficiency is literally raised as the temperature decreases, a direct consequence of enhanced charge-balance factor. It is also demonstrated that the EL delay upon turn-on is mostly determined by the electron transport through the electron transport layer (ETL), while the fast EL decay (short-lived EL tail) upon turn-off is mainly by the rapid discharge of the steep pileup of carriers at the NPD/Alq <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interface. The long-lived EL tail is shown to be more pronounced under lower temperatures. In response to a train of voltage pulses, the delay of EL occurring for the first voltage pulse has vanished for the subsequent pulses regardless of temperature due to space charges remaining inside the device after turn-off (in the "off-state"). However, it appears that the pulse-to-pulse interference by the space charge effects is more significant under lower temperatures

Inflow Stenoses in Dysfunctional Hemodialysis Access Fistulae and Grafts

The aim of the study is to prospectively determine the incidence of inflow stenoses in dysfunctional hemodialysis access arteriovenous fistulae (AVFs) and grafts (AVGs). Contrast-enhanced magnetic resonance angiography (CE-MRA) was performed of 66 dysfunctional AVFs and 35 AVGs in 56 men and 45 women (mean age, 62 years; age range, 31 to 86 years). Complete inflow (from the subclavian artery), shunt region, and complete outflow (including subclavian vein) were shown at CE-MRA. In addition to standard digital subtraction angiography (DSA) of the shunt region and outflow, DSA of the complete inflow was obtained through access catheterization of all cases in which CE-MRA showed an inflow stenosis. Vascular stenosis is defined as greater than 50% decrease in luminal diameter compared with an uninvolved vascular segment located adjacent to the stenosis. Endovascular intervention of stenoses was performed in connection with DSA. CE-MRA showed 19 arterial stenoses in 14 patients (14%). DSA confirmed 18 of these lesions in 13 patients and showed no additional inflow lesions. Of the 13 patients, 7 patients had arterial stenoses only and 6 patients had accompanying stenoses in the shunt region and/or outflow. Referral criteria for the 13 patients to undergo access evaluation had been decreased flow rates (9 patients), steal symptoms (2 patients), and insufficient access maturation (2 patients). Access flow of the 9 patients with a low-flow access improved from 477 +/- 74 mL/min to 825 +/- 199 mL/min after angioplasty. One patient with steal symptoms became symptom free after angioplasty. Endovascular intervention in 3 patients proved to be unsuccessful. Inflow stenoses are not uncommon in dysfunctional hemodialysis access shunts. We suggest that radiological evaluation comprise assessment of the complete arterial inflow.

Depressive Symptoms, Social Isolation, and Progression of Coronary Artery Atherosclerosis: The Stockholm Female Coronary Angiography Study

Background: Although both depressive symptoms and social isolation in relation to coronary heart disease have been studied previously, few have examined their joint effects on coronary atherosclerosis progression in women. Method: Among the women enrolled in the Stockholm Female Coronary Angiography Study, Sweden, between 1991 and 1994, 102 were evaluated for coronary atherosclerosis progression using a computer-assisted standardized assessment, repeated quantitative coronary angiographic documentation, of the mean luminal diameter change over 3 years in 10 predefined coronary segments. Depressive symptoms and social isolation were assessed by standard questionnaires. Results: Multivariable controlled mixed model ANOVAs revealed that women who were both depressed and socially isolated had the greatest disease progression: their absolute mean luminal diameter decreased by 0.18 mm [95% confidence interval (CI) = 0.11–0.24] and their percent narrowing was 5.5% (95% CI = 3.6–7.4), whereas in women who lacked both psychological risk factors, the mean luminal diameter decrease was 0.04 mm and their percent narrowing was 0.9%. These associations were independent of the baseline luminal diameter and standard risk factors, including age, smoking history, hypertension, and high-density lipoproteins. Conclusions:In women with coronary disease, depressive symptoms and social isolation in combination accelerated disease progression, suggesting a direct psychosocial effect on the atherosclerotic process. These findings provide an additional opportunity for therapeutic and preventive efforts against progression of coronary disease in women.

On BaMgAl10O17:Eu2+ phosphor degradation mechanism by vacuum-ultraviolet excitation

Additional to a correct color and a high efficiency, phosphors for plasma display panels must maintain their light output for thousands of hours. Often the degradation is the restricting factor in using phosphors. In this article, the mechanism of luminance decrease in blue-emitting BaMgAl10O17:Eu2+ phosphor during the operation of the PDPs has been studied. It is shown experimentally that the aging process is mainly due to the vacuum-ultraviolet excitation (VUV). It is demonstrated that the degradation mechanism can be accelerated by using a 193nm laser excitation. Based on excitation, reflectance, thermoluminescence spectra, and aging or annealing processes by laser excitation, the main causes of the degradation are demonstrated. The aging process can be separated in two different processes according to the temperature: a first one, at low temperature, corresponding to the autoionization of luminescent centers (Eu2+→Eu3+); and a second one, at high temperature, linked to the formation of traps in the phosphor. These traps induce a perturbation of the energy migration in the phosphor. In addition, the relevant parameters of trap formation are highlighted: density of the VUV excitation, temperature, and atmosphere/pressure surrounding the phosphor. A model of BaMgAl10O17:Eu2+ phosphor degradation mechanism is proposed.

Degradation mechanism of phosphors by vacuum ultraviolet excitation

The mechanism of luminance decrease of phosphors excited by a Xe plasma discharge has been studied. It is shown experimentally that the aging process is mainly due to the vacuum ultraviolet excitation (VUV). It is demonstrated that the degradation mechanism can be accelerated by using 193 nm laser excitation. Based on excitation, reflectance, thermoluminescence spectra and ageing or bleaching processes by laser excitation, the main causes of the degradation are demonstrated. The aging process can be separated in two different processes depending on the temperature: a first one, at low temperature, corresponding to the autoionisation of luminescent centers; and a second one, at high temperature, linked to the formation of traps in the phosphor. These traps induce a perturbation of the energy migration in the phosphor. The relevant parameters of the creation of traps are highlighted: density of the VUV excitation, temperature, atmosphere and pressure surrounding the phosphor.

Role of Aeration in the Physiological Adaptation of the Lung to Air- Breathing at Birth

At birth, the successful transition to extra-uterine life is dependent upon the ability of the lung to take over the role of respiratory gas-exchange. Before birth, the future airways of the lungs are filled with a liquid that is produced by the lung and leaves the lungs by flowing out of the trachea. At rest, adduction of the larynx restricts lung liquid efflux and promotes its retention within the airways, thereby generating a 1- 2mmHg internal distending pressure on the lung. At birth the airways must be cleared of liquid to allow the entry of air, but a thin film must remain to protect the epithelium from desiccation. This creates an air/liquid interface across the large internal surface of the lung which increases lung recoil, despite the presence of surfactant. Thus, after birth, the loss of the distending influence of lung liquid, and the increase in lung recoil associated with lung aeration greatly alters the distribution of forces exerted within lung tissue. As a result, lung luminal volumes decrease and the tendency for the lung to collapse away from the chest wall increases, leading to the creation of a sub-atmospheric intra-pleural pressure. Until recently, the role of lung aeration and the resultant changes in physical forces, have been over-looked as factors regulating the normal changes in lung physiology that are required for the lung to adopt the role of respiratory gas exchange at birth. As these changes in the respiratory system are essential for the independent survival of the newborn infant after birth, it is important to understand the mechanisms involved so that these changes are not impeded in the sick, ventilated very preterm infant. At birth numerous changes in lung physiology occur which transform the respiratory system into an efficient gas-exchange system. For instance, the number of surfactant secreting type-II epithelial cells increases, chest wall compliance decreases and pulmonary blood flow (PBF) markedly increases. One of the most remarkable changes in lung physiology that occurs at birth is the large increase in PBF, resulting from a marked decrease in pulmonary vascular resistance (PVR). Before birth, most (∼88%) of right ventricular output by-passes the lungs and passes through the ductus arteriosus (DA) into the systemic circulation. This is primarily attributed to the high PVR in the fetus which is also responsible for the unique PBF waveform contour, which is mainly characterized by a large retrograde, flow of blood away from the lungs during diastole; this blood exits the pulmonary circulation via the DA. At birth, the rapid decrease in PVR causes marked changes in the contour of the PBF waveform with the disappearance of the negative or retrograde component. As a result, forward flow occurs throughout the cardiac cycle. Although many factors are thought to contribute to this decrease in PVR at birth, the accumulating evidence indicates that a change in the distribution of forces within lung tissue is a major contributing factor. Other changes in the lung that occur at birth include a change in the relative proportions of type-I and type-II epithelial cells and a gradual stiffening of the chest wall to enhance breathing efficiency. Although these changes, including the changes in PVR, are usually assumed to be independent events, recent evidence suggests that they are inter-related and that they are precipitated by the replacement of lung liquid with air. In this review, our primary aims are to discuss how the presence of liquid-filled airways influences lung physiology in the fetus and the role that changing the internal environment of the lung from liquid to air plays in the adaptation of the respiratory system to air-breathing at birth. It is important to understand these interrelationships as positive pressure ventilation can oppose these changes in lung physiology. Thus, in very preterm infants (born < 30 weeks GA), who require resuscitation and assisted ventilation during their first weeks of life, it is important to adopt ventilation strategies that do not impede these normal physiological changes.

On [formula omitted] phosphor degradation mechanism: thermal treatment effects

Fluorescence characteristics degradation mechanisms of plasma display panels (PDP) phosphor during panel fabrication and during panel life are not yet fully clarified. We present here the mechanism of luminance decrease in blue-emitting BaMgAl 10 O 17 : Eu 2 + phosphor due to the baking process, one step of the panel fabrication. It was shown experimentally that annealing in air leads to the oxidation of the dopant. It was demonstrated that during the oxidation process the decrease of divalent europium concentration is followed by an increase in the trivalent europium concentration but also by a decrease in the traps concentration. Based on these results and a numerical simulation, we proposed a model of the oxidation process. The degradation is due to three different mechanisms: the adsorption of an oxygen atom of the atmosphere into an oxygen vacancy of the surface phosphor, the diffusion of divalent europium ions along the conduction layer of BAM and the transfer of one electron from dopant ions to adsorbed oxygen ions when the divalent europium ions are close to adsorbed oxygen ions. We also develop two different solutions to stop or to minimize the degradation due to the baking process.

Light propagation tuned by periodic junction-prisms within well-faceted ZnO fibers

Well-faceted ZnO fibers with periodic junction-prisms were synthesized using conventional chemical vapor deposition. The characterization of the fibers by optical and fluorescence microscopy showed that the outer facets of the crystalline fibers provide excellent mirror-like surfaces for guiding light propagation along the fiber stem as well as the periodic junction-prisms. The structure-related optical properties can be fully explained by a microstructural model. The proposed model explains as the decrease in luminance at the junction-prisms is caused by refraction and total or partial reflection of light. The model also explains the luminance enhancement at the junction-prisms is related to waveguiding of the green emission of the ZnO fibers. Further integration of the ZnO junction-prisms into microdevices should provide the microscale modulation for light with different wavelengths, and could be potentially used for enhanced light-illumination arrays.

A review on ZnS phosphor degradation

Standard ZnS cathodoluminescent phosphors normally lose brightness upon bombardment with electron beams. The main reason for the degradation is the formation of a non-luminescent “dead layer” on the surface due to the electron stimulated surface chemical reaction (ESSCR) mechanism. The decrease in luminance was found to be a result of the growth of the “dead layer”. Calculations showed that the thickness of the oxide layer that formed during electron bombardment, cannot completely explain the magnitude of the decline of the CL intensity. Iso-electronic point defects due to the presence of oxygen that diffuse into the ZnS matrix at the interface further contribute to the degradation. When the ZnS phosphor powder was exposed to the electron beam in a water-rich O2 ambient, a chemically-limited ZnO layer was formed on the surface. A layer of ZnSO4 was formed on the surface during the electron beam degradation of the ZnS phosphor powder in a dry O2 ambient. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Angular dependence of the luminance and contrast in medical monochrome liquid crystal displays.

Active-matrix liquid crystal displays (AMLCDs) are light-modulating devices that generate images by differentially transmitting a nearly uniform luminous field provided by a backlight. While emissive displays exhibit a quasi-Lambertian emission with almost constant contrast at off-normal viewing, the anisotropy of the electro-optic effect that controls light transmission in AMLCDs causes a pixel luminance that varies, sometimes strongly, with viewing angle. These variations are not identical for all gray levels and can eventually cause grayscale inversions. In this paper, we measured the luminance emission of a monochrome medical AMLCD, a medical cathode-ray tube monitor, and a color desktop AMLCD, using a collimated photopic probe positioned on a manual rotation arm, and a research radiometer with automatic readout. The probe measures luminance with a small acceptance angle and provides optical shielding from emissions at other viewing directions that contaminate the readings. We obtained luminance response curves versus angle in the vertical, horizontal and at 45 degrees diagonal directions. The display systems were calibrated to reflect the DICOM Part 3.14 standard grayscale display function (GDF) when measured using the manufacturer's probe and software tools. We analyzed the measurements at different viewing directions with respect to their departure from the GDF by computing the normalized contrast (deltaL/L) as a function of the DICOM just-noticeable difference index. Although cathode-ray tubes are known to be quasi-Lambertian emitters, the luminance at normal viewing is higher than the luminance observed at large angles. This decrease in luminance is however proportionally similar for all gray levels, resulting in a relatively flat contrast response for all angles. In addition to being more pronounced, the angular variation in AMLCDs does not follow the same profile at different intensities with the subsequent variation in the achieved display contrast. The changes due to off-normal viewing are substantial at large angles in the horizontal and vertical directions, and much worse in the diagonal viewing directions.

Quantitative characterization of visual response properties in the mouse dorsal lateral geniculate nucleus.

We present a quantitative analysis of the visual response properties of single neurons in the dorsal lateral geniculate nucleus (dLGN) of wild-type C57Bl/6J mice. Extracellular recordings were made from single dLGN cells in mice under halothane and nitrous oxide anesthesia. After mapping the receptive fields (RFs) of these cells using reverse correlation of responses to flashed square stimuli, we used sinusoidal gratings to describe their linearity of spatial summation, spatial frequency tuning, temporal frequency tuning, and contrast response characteristics. All cells in our sample had RFs dominated by a single, roughly circular "center" mechanism that responded to either increases (ON-center) or decreases (OFF-center) in stimulus luminance, and almost all cells passed a modified null test for linearity of spatial summation. A difference of Gaussians model was used to relate spatial frequency tuning to the spatial properties of cells' RFs, revealing that mouse dLGN cells have large RFs (center diameter approximately 11 degrees) and correspondingly poor spatial resolution (approximately 0.2c/degree). Temporally, most cells in the mouse dLGN respond best to stimuli of approximately 4 Hz. We looked for evidence of parallel processing in the mouse dLGN and found it only in a functional difference between ON- and OFF-center cells: ON-center cells were more sensitive to stimulus contrast than their OFF-center neighbors.