Brightness In The Photopic Range: Psychophysical Modelling With Blue-sensitive Retinal Signals

2020 ◽  
pp. 9-24
Author(s):  
Peter Bodrogi ◽  
Xue Guo ◽  
Tran Quoc Khanh
Keyword(s):  
Ganglion Cells ◽  
Light Stimulus ◽  
Spectral Radiance ◽  
Psychophysical Experiment ◽  
Retinal Ganglion ◽  
Reasonable Accuracy ◽  
Brightness Perception ◽  
Content Model ◽  
The Difference ◽  
Cone Signal

The brightness perception of a large (41°) uniform visual field was investigated in a visual psychophysical experiment. Subjects assessed the brightness of 20 light source spectra of different chromaticities at two luminance levels, Lv=267.6 cd/m2 and Lv=24.8 cd/m2. The resulting mean subjective brightness scale values were modelled by a combination of the signals of retinal mechanisms: S-cones, rods, intrinsically photosensitive retinal ganglion cells (ipRGCs) and the difference of the L-cone signal and the M-cone signal. A new quantity, “relative spectral blue content”, was also considered for modelling. This quantity was defined as “the spectral radiance of the light stimulus integrated with the range (380–520) nm, relative to luminance”. The “relative spectral blue content” model could describe the subjective brightness perception of the observers with reasonable accuracy.

scholarly journals Effect of Acupuncture on Intraocular Pressure in Glaucoma Patients: A Single-Blinded, Randomized, Controlled Trial

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Shu-Yuan Chen ◽  
Feng-Shuen Yieh ◽  
Wen-Ling Liao ◽  
Tsai-Chung Li ◽  
Ching-Liang Hsieh
Keyword(s):  
Randomized Controlled Trial ◽  
Intraocular Pressure ◽  
Sham Group ◽  
Ganglion Cells ◽  
Controlled Trial ◽  
Ocular Blood Flow ◽  
Retinal Ganglion ◽  
Randomized Controlled ◽  
Ocular Perfusion ◽  
The Difference

Glaucoma is characterized by the degeneration of retinal ganglion cells that cause progressive optic neuropathy, finally resulting in changes to the optic nerve head. Lowering intraocular pressure (IOP) is the only method proven for treating glaucoma. Several studies have discovered that acupuncture can reduce IOP and also increase ocular perfusion and ocular blood flow. Therefore, the present study investigated the effect of acupuncture on IOP in glaucoma patients. We conducted a single-blinded, randomized, controlled trial involving 45 glaucoma patients. The results indicated that the difference between the IOP 60 min after the intervention and IOP immediately before the intervention was greater in the acupuncture group (AG) and electroacupuncture group (EG) than in the sham group (SG) for all four of the interventions performed and in both eyes (all p<0.05). The IOP difference between immediately before the first intervention and after finishing the final intervention was also greater in the AG and EG than in the SG in both eyes (all p<0.05). In conclusion, IOP was reduced at 60 min after acupuncture or electroacupuncture was performed at BL1 and EX-HN7. Additionally, IOP was reduced after finishing four acupuncture or electroacupuncture sessions. Therefore, our results suggest that acupuncture and electroacupuncture are beneficial for lowering IOP in glaucoma patients. This trial is registered with NCT04157530.

Investigating visual mechanisms underlying scene brightness

2016 ◽  
Vol 49 (1) ◽  
pp. 16-32 ◽  
Author(s):  
UC Besenecker ◽  
JD Bullough
Keyword(s):  
Retinal Ganglion Cells ◽  
Spectral Sensitivity ◽  
Short Wavelength ◽  
Ganglion Cells ◽  
Forced Choice ◽  
Light Sources ◽  
Retinal Ganglion ◽  
Brightness Perception ◽  
Light Levels ◽  
Relative Brightness

Short-wavelength (<500 nm) output of light sources enhances scene brightness perception in the low-to-moderate photopic range. This appears to be partially explained by a contribution from short-wavelength cones. Recent evidence from experiments on humans suggests that intrinsically photosensitive retinal ganglion cells (ipRGCs) containing the photopigment melanopsin might also contribute to spectral sensitivity for scene brightness perception. An experiment was conducted to investigate this possibility at two different light levels, near 10 lx and near 100 lx. Subjects provided forced-choice brightness judgments and relative brightness magnitude judgments when comparing two different amber-coloured stimuli with similar chromaticities. A provisional brightness metric including an ipRGC contribution was able to predict the data with substantially smaller errors than a metric based on cone input only.

scholarly journals Salamander retinal ganglion cell responses to rich stimuli

2020 ◽  
Author(s):  
Kolia Sadeghi ◽  
Michael J. Berry
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Spatial Information ◽  
Ganglion Cells ◽  
Light Stimulus ◽  
Linear Filter ◽  
Retinal Ganglion ◽  
Linear Filters ◽  
Cell Responses ◽  
Random Stimulus

AbstractThe retina’s phenomenological function is often considered to be well-understood: individual retinal ganglion cells are sensitive to a projection of the light stimulus movie onto a classical center-surround linear filter. Recent models elaborating on this basic framework by adding a second linear filter or spike histories, have been quite successful at predicting ganglion cell spikes for spatially uniform random stimuli, and for random stimuli varying spatially with low resolution. Fitting models for stimuli with more finely grained spatial variations becomes difficult because of the very high dimensionality of such stimuli. We present a method of reducing the dimensionality of a fine one dimensional random stimulus by using wavelets, allowing for several clean predictive linear filters to be found for each cell. For salamander retinal ganglion cells, we find in addition to the spike triggered average, 3 identifiable types of linear filters which modulate the firing of most cells. While some cells can be modeled fairly accurately, many cells are poorly captured, even with as many as 4 filters. The new linear filters we find shed some light on the nonlinearities in the retina’s integration of temporal and fine spatial information.

Summation of Quantal Noise in Space and Time

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 175-175
Author(s):  
S Hemilä ◽  
T Lerber ◽  
K Donner
Keyword(s):  
Ganglion Cells ◽  
Signal To Noise Ratio ◽  
Light Flux ◽  
Equal Weight ◽  
Retinal Ganglion ◽  
Quantal Response ◽  
Visual Neurons ◽  
Space And Time ◽  
The Difference ◽  
Definition Of

Noise in visual neurons, or variability in psychophysical experiments, may be quantified in terms of photon fluctuations from an ‘equivalent’ steady illumination. The conversion requires assumptions on how photon signals are pooled in space and time, ie how to pass from the light flux to the numbers of photon events relevant to the Poisson statistics describing signal/noise. Real weighting profiles for the integration of photon events in space and time [the sensitivity distribution of the receptive field (RF) and the waveform of the impulse response (IR)] are commonly approximated by sharp-bordered apertures of ‘complete’, equal-weight summation of events. Such apertures based on signal equivalence cannot provide noise equivalence, however, because greater numbers of events summed with lower weights (as in reality) have lower variances than smaller numbers summed with full weight. Thus sharp-bordered apertures are necessarily smaller if defined for noise equivalence rather than for signal equivalence. We have calculated the difference for some commonly encountered RF and IR profiles. Summation areas, expressed as numbers of photoreceptors (cones or rods) contributing with equal weight, are denoted NS for signal and NN for noise, and sharply delimited summation times are correspondingly denoted tS and tN. We show that the relation in time is tN=0.6 tS to 0.7 tS for realistic quantal response waveforms of photoreceptors. In space, the relation is NN=0.5 NS for the Gaussian distribution (eg for the RF centre mechanism of retinal ganglion cells). For a photoreceptor in an electrically coupled network the difference is still greater, eg for rods in the toad retina NN=0.2 NS ( NS=13.7 rods and NN=2.8 rods). We introduce a third possible definition of sharp-bordered summation apertures: one that provides the same signal-to-noise ratio (SNR) for large-long stimuli as the real integration profiles. The SNR-equivalent summation area is N*= NS2/ NN and the summation time is t*= tS2/ tN.

scholarly journals Studying a Light Sensor with Light: Multiphoton Imaging in the Retina

2019 ◽  
Author(s):  
Thomas Euler ◽  
Katrin Franke ◽  
Tom Baden
Keyword(s):  
Retinal Ganglion Cells ◽  
Neuronal Activity ◽  
Ganglion Cells ◽  
Light Stimulus ◽  
Retinal Ganglion ◽  
Multiphoton Imaging ◽  
Vertebrate Retina ◽  
Two Photon ◽  
All Optical ◽  
The Brain

Two-photon imaging of light stimulus-evoked neuronal activity has been used to study all neuron classes in the vertebrate retina, from the photoreceptors to the retinal ganglion cells. Clearly, the ability to study retinal circuits down to the level of single synapses or zoomed out at the level of complete populations of neurons, has been a major asset in our understanding of this beautiful circuit. In this chapter, we discuss the possibilities and pitfalls of using an all-optical approach in this highly light-sensitive part of the brain.

Survival of retinal ganglion cells after transection of the optic nerve in adult cats: A quantitative study within two weeks

2001 ◽  
Vol 18 (1) ◽  
pp. 137-145 ◽  
Author(s):  
MASAMI WATANABE ◽  
NAOKO INUKAI ◽  
YUTAKA FUKUDA
Keyword(s):  
Optic Nerve ◽  
Retinal Ganglion Cells ◽  
Time Course ◽  
Ganglion Cells ◽  
Lucifer Yellow ◽  
Retinal Ganglion ◽  
Β Cells ◽  
Fiber Layer ◽  
The Difference ◽  
Adult Cats

We have previously reported that a small number of retinal ganglion cells (RGCs) of adult cats survive 2 months after transection of the optic nerve (ON) and that α cells have the greatest ability to survive among different types of RGCs (Watanabe et al., 1995). Here we report the time course of RGC survival within 15 days after ON transection using retrograde labeling with DiI injected into the bilateral lateral geniculate nuclei of cats. The density of DiI-labeled RGCs in the central retina as well as in the periphery did not change until day 3 after ON transection, then decreased rapidly, to 43% of the original density on day 7, and falling to 19% by day 14. We then intracellularly injected Lucifer yellow into the DiI-labeled RGCs to examine the difference in the time course between surviving α and β cells. Similar to the density change in total surviving RGCs, the proportion of surviving β cells did not change until day 3, then decreased rapidly to 65% of the original density on day 4, falling to 12% by day 14. By contrast, 64% of α cells survived for 14 days after axotomy. Analysis of regression lines for survival time courses indicated that death of β cells was characterized with a rapid period phase from day 3 to day 7 after axotomy whereas that of α cells lacked it. Axon-like sprouting from surviving β cells was first recognized in the nerve fiber layer on day 3, and were later more conspicuous.

Correlated Firing in Rabbit Retinal Ganglion Cells

1999 ◽  
Vol 81 (2) ◽  
pp. 908-920 ◽  
Author(s):  
Steven H. DeVries
Keyword(s):  
Receptive Field ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Light Stimulus ◽  
Receptive Fields ◽  
Multielectrode Array ◽  
Retinal Ganglion ◽  
Retinal Surface ◽  
Multiple Electrodes ◽  
Independent Decision

Correlated firing in rabbit retinal ganglion cells. A ganglion cell’s receptive field is defined as that region on the retinal surface in which a light stimulus will produce a response. While neighboring ganglion cells may respond to the same stimulus in a region where their receptive fields overlap, it generally has been assumed that each cell makes an independent decision about whether to fire. Recent recordings from cat and salamander retina using multiple electrodes have challenged this view of independent firing by showing that neighboring ganglion cells have an increased tendency to fire together within ±5 ms. However, there is still uncertainty about which types of ganglion cells fire together, the mechanisms that produce coordinated spikes, and the overall function of coordinated firing. To address these issues, the responses of up to 80 rabbit retinal ganglion cells were recorded simultaneously using a multielectrode array. Of the 11 classes of rabbit ganglion cells previously identified, coordinated firing was observed in five. Plots of the spike train cross-correlation function suggested that coordinated firing occurred through two mechanisms. In the first mechanism, a spike in an interneuron diverged to produce simultaneous spikes in two ganglion cells. This mechanism predominated in four of the five classes including the onbrisk transient cells. In the second mechanism, ganglion cells appeared to activate each other reciprocally. This was the predominant pattern of correlated firing in off brisk transient cells. By comparing the receptive field profiles of on andoff brisk transient cells, a peripheral extension of theoff brisk transient cell receptive field was identified that might be produced by lateral spike spread. Thus an individualoff brisk transient cell can respond both to a light stimulus directed at the center of its receptive field and to stimuli that activate neighboring off brisk transient cells through their receptive field centers.

Melanopsin-dependent phototransduction is impaired in delayed sleep–wake phase disorder and sighted non–24-hour sleep–wake rhythm disorder

SLEEP ◽  
2020 ◽  
Author(s):  
Sabra M Abbott ◽  
Jin Choi ◽  
John Wilson ◽  
Phyllis C Zee
Keyword(s):  
Ganglion Cells ◽  
Light Stimulus ◽  
Red Light ◽  
Control Group ◽  
Environmental Light ◽  
History Of ◽  
Rhythm Disorder ◽  
The Difference ◽  
Delayed Sleep ◽  
Stimulus Offset

Abstract Study Objectives The circadian system must perform daily adjustments to align sleep–wake and other physiologic rhythms with the environmental light–dark cycle: This is mediated primarily through melanopsin containing intrinsically photosensitive retinal ganglion cells. Individuals with delayed sleep–wake phase disorder (DSWPD) exhibit a delay in sleep–wake timing relative to the average population, while those with sighted non–24-hour sleep–wake rhythm disorder (N24SWD) exhibit progressive delays. An inability to maintain appropriate entrainment is a characteristic of both disorders. In this study, we test the hypothesis that individuals with DSWPD exhibit alteration in melanopsin-dependent retinal photo-transduction as measured with the postillumination pupil response (PIPR). Methods Twenty-one control and 29 participants with DSWPD were recruited from the community and clinic. Of the 29 DSWPD participants, 17 reported a history of N24SWD. A pupillometer was used to measure the PIPR in response to a bright 30-second blue or red-light stimulus. The PIPR was calculated as the difference in average pupil diameter at baseline and 10–40 seconds after light stimulus offset. Results The PIPR was significantly reduced in the DSWPD group when compared with the control group (1.26 ± 1.11 mm vs 2.05 ± 1.04 mm, p &lt; 0.05, t-test). The PIPR was significantly reduced in the sighted N24SWD subgroup when compared with individuals with the history of only DSWPD (0.88 ± 0.58 mm vs 1.82 ± 1.44 mm, p &lt; 0.05, analysis of variance [ANOVA]) or controls (0.88 ± 0.58 mm vs 2.05 ± 1.04 mm, p &lt; 0.01, ANOVA). Conclusions These results indicate that reduced melanopsin-dependent retinal photo-transduction may be a novel mechanism involved in the development of DSWPD and sighted N24SWD.

scholarly journals Scalable and accurate automated method for neuronal ensemble detection in spiking neural networks

2020 ◽  
Author(s):  
Rubén Herzog ◽  
Arturo Morales ◽  
Soraya Mora ◽  
Joaquin Araya ◽  
María-José Escobar ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Light Stimulus ◽  
Synthetic Data ◽  
Retinal Ganglion ◽  
Electrode Arrays ◽  
Neuronal Ensembles ◽  
Automated Method ◽  
Wide Range ◽  
Ensemble Activity

AbstractWe propose a novel, scalable, and accurate automated method for detecting neuronal ensembles from a population of spiking neurons. Our approach offers a simple yet powerful tool to study ensemble activity. It allows the participation of neurons in different ensembles, has few parameters to tune and is computationally efficient. We used spike trains of retinal ganglion cells obtained from multi-electrode array recordings under a simple ON-OFF light stimulus to test our method. We found a consistent stimuli-evoked ensemble activity intermingled with spontaneously active ensembles and irregular activity. Our results suggest that the early visual system activity is already organized in clearly distinguishable functional ensembles. To validate the performance and generality of our method, we generated synthetic data, where we found that our method accurately detects neuronal ensembles for a wide range of simulation parameters. Additionally, we found that our method outperforms current alternative methodologies. Finally, we provide a Graphic User Interface, which aims to facilitate our method’s use by the scientific community.Author summaryNeuronal ensembles are strongly interconnected groups of neurons that tend to fire together (Hebb 1949). However, even when this concept was proposed more than 70 years ago, only recent advances in multi-electrode arrays and calcium imaging, statistical methods, and computing power have made it possible to record and analyze multiple neurons’ activities spiking simultaneously, providing a unique opportunity to study how groups of neurons form ensembles spontaneously and under different stimuli scenarios. Using our method, we found that retinal ganglion cells show a consistent stimuli-evoked ensemble activity, and, when validated with synthetic data, the method shows good performance by detecting the number of ensembles, the activation times, and the core-cells for a wide range of firing rates and number of ensembles accurately.

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