scholarly journals A novel setup for simultaneous two-photon functional imaging and precise spectral and spatial visual stimulation in Drosophila

2020 ◽  
Author(s):  
R. C. Feord ◽  
T. J. Wardill
Keyword(s):  
Large Range ◽  
Visual Stimulation ◽  
Spectral Response ◽  
Visible Spectrum ◽  
Optical Filters ◽  
Visual Responses ◽  
Motion Vision ◽  
Response Properties ◽  
Two Photon ◽  
Processing Colour

ABSTRACTMotion vision has been extensively characterised in Drosophila melanogaster, but substantially less is known about how flies process colour, or how spectral information affects other visual modalities. To accurately dissect the components of the early visual system responsible for processing colour, we developed a versatile visual stimulation setup to probe combined spatial, temporal and spectral response properties. Using flies expressing neural activity indicators, we tracked visual responses in the medulla to a projected colour stimulus. The introduction of custom bandpass optical filters enables simultaneous two-photon imaging and visual stimulation over a large range of wavelengths without compromising the temporal stimulation rate. With monochromator-produced light, any spectral bandwidth and centre wavelength from 390 to 730 nm can be selected to produce a narrow spectral hue. A specialised screen material scatters each band of light across the visible spectrum equally at all locations of the screen, thus enabling presentation of spatially structured stimuli. We show layer-specific shifts of spectral response properties in the medulla correlating with projection regions of photoreceptor terminals.

scholarly journals A novel setup for simultaneous two-photon functional imaging and precise spectral and spatial visual stimulation in Drosophila

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rachael C. Feord ◽  
Trevor J. Wardill
Keyword(s):  
Large Range ◽  
Visual Stimulation ◽  
Spectral Response ◽  
Visible Spectrum ◽  
Optical Filters ◽  
Visual Responses ◽  
Motion Vision ◽  
Response Properties ◽  
Two Photon ◽  
Processing Colour

Abstract Motion vision has been extensively characterised in Drosophila melanogaster, but substantially less is known about how flies process colour, or how spectral information affects other visual modalities. To accurately dissect the components of the early visual system responsible for processing colour, we developed a versatile visual stimulation setup to probe combined spatial, temporal and spectral response properties. Using flies expressing neural activity indicators, we tracked visual responses in the medulla, the second visual neuropil, to a projected colour stimulus. The introduction of custom bandpass optical filters enables simultaneous two-photon imaging and visual stimulation over a large range of wavelengths without compromising the temporal stimulation rate. With monochromator-produced light, any spectral bandwidth and centre wavelength from 390 to 730 nm can be selected to produce a narrow spectral hue. A specialised screen material scatters each band of light across the visible spectrum equally at all locations of the screen, thus enabling presentation of spatially structured stimuli. We show layer-specific shifts of spectral response properties in the medulla correlating with projection regions of photoreceptor terminals.

scholarly journals Two-Photon Microperimetry: A media opacity-independent retinal function assay

2020 ◽  
Author(s):  
Ang Wei ◽  
Urmi V. Mehta ◽  
Grazyna Palczewska ◽  
Anton M. Palma ◽  
Vincent M. Hussey ◽  
...  
Keyword(s):  
Visible Light ◽  
Visual Function ◽  
Visual Stimulation ◽  
Visible Spectrum ◽  
Contrast Threshold ◽  
Retinal Sensitivity ◽  
Two Photon ◽  
Optical Media ◽  
Media Opacities ◽  
Function Testing

AbstractHumans perceive light in the visible portion of electromagnetic radiation. However, visible light is scattered and attenuated by optical media opacities. Because all conventional visual function tests rely on visible light, test results are reduced in patients with optical media opacities like corneal scars, cataracts, and vitreous hemorrhages. Infrared (IR) light has greater penetrance through tissue than visible light. Two-photon IR visual stimulation, a recently pioneered technology, should enable testing of retinal visual function and produce results that are less susceptible to media opacities. The effects of simulated media opacities on visual performance in young healthy volunteers and the change in visual function in healthy phakic patients of two age ranges (20-40 and 60-80-year-old) were studied using conventional testing and 2-photon infrared visual stimulation. All subjects completed visual function testing using cone contrast threshold (CCT) testing, conventional microperimetry, visible light microperimetry from a novel device (2PM-Vis), and infrared 2-photon microperimetry (2PM-IR). Retinal sensitivity measured by 2PM-IR demonstrated lower variability than all other devices relying on visible spectrum stimuli. Retinal sensitivity decreased proportionally with the transmittance of light through each filter. CCT scores and retinal sensitivity decreased with age in all testing modalities. Visible spectrum testing modalities demonstrated larger test result differences between young and old patient cohorts; this difference was inversely proportional to the wavelength of the visual function test. 2PM-IR mitigates media opacities which may mask small differences in retinal sensitivity when tested with conventional visual function testing devices.One Sentence SummaryTwo photon infrared visual function testing produces results that are less susceptible to media opacities than conventional tests.

Use of a-SiC:H multilayer transducers for detection of fluorescence signals from reactive cyan and yellow fluorophores

2011 ◽  
Vol 1321 ◽  
Author(s):  
P. Louro ◽  
M. Vieira ◽  
M. A. Vieira ◽  
J. Costa ◽  
M. Fernandes ◽  
...  
Keyword(s):  
Spectral Response ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Optical Filters ◽  
Electrical Model ◽  
Excitation Light ◽  
Independent Test ◽  
Opposite Behavior ◽  
Blue Background ◽  
Insight Into

ABSTRACTThe transducer consists of a p-i’(a-SiC:H)-n/p-i(a-Si:H)-n heterostructures produced by PECVD and optimized for the detection of the fluorescence resonance energy transfer between fluorophores with excitation in the violet(400 nm) and emissions in the cyan (470 nm) and yellow (588 nm) range of the spectrum. The thickness and the absorption coefficient of the i’- and i- layers were tailored for cyan and yellow optical confinement, respectively in the front and back photodiodes acting both as optical filters. The devices were characterized through transmittance and spectral response measurements and under different electrical.To simulate the FRET pairs and the excitation light a chromatic time dependent combination of violet, cyan and yellow wavelengths was applied to the device. The generated photocurrent was measured under negative and positive bias to readout the combined spectra. The independent test signals were chosen in order to sample all the possible chromatic. Different wavelength backgrounds were also superimposed.Results show that under negative bias the phorocurrent signal presents eight separate levels each one assigned to the different polychromatic mixtures. If a blue background is superimposed the yellow channel is enhanced and the cyan suppressed while under red irradiation the opposite behavior occurs. So under appropriated steady state optical bias the sensor will detect separately the cyan and yellow fluorescence pairs. An electrical model, supported by a numerical simulation, gives insight into the transduction mechanism.

Organic photodetector with spectral response tunable across the visible spectrum by means of internal optical microcavity

2009 ◽  
Vol 10 (6) ◽  
pp. 1152-1157 ◽  
Author(s):  
Kwang Hyup An ◽  
Brendan O’Connor ◽  
Kevin P. Pipe ◽  
Max Shtein
Keyword(s):  
Spectral Response ◽  
Visible Spectrum ◽  
Optical Microcavity ◽  
Organic Photodetector

scholarly journals DIGITAL IMAGE ANALYSIS OF THE VISIBLE REGION THROUGH SIMULATION OF ROCK ART PAINTINGS

2016 ◽  
Author(s):  
Berta Carrión-Ruiz ◽  
Silvia Blanco-Pons ◽  
Jose Luis Lerma
Keyword(s):  
Rock Art ◽  
Visible Region ◽  
Visible Spectrum ◽  
Principal Component ◽  
Optical Filters ◽  
Visible Range ◽  
Redundant Data ◽  
The Difference ◽  
Entire Visible Spectrum ◽  
New Research

Non-destructive rock art recording techniques are getting special attention in the last years, opening new research lines in order to improve the level of documentation and understanding of our rich legacy. This paper applies the principal component analysis (PCA) technique in images that include wavelengths between 400-700 nm (visible  range). Our approach is focused on determining the difference provided by the image processing of the visible region through four spectral images versus an image that encompasses the entire visible spectrum. The images were taken by means of optical filters that take specific wavelengths and exclude parts of the spectrum. Simulation of rock art is prepared in laboratory. For this purpose, three different pigments were made simulating the material composition of rock art paintings. The advantages of studying the visible spectrum in separate images are analysed. In addition, PCA is applied to each of the images to reduce redundant data. Finally, PCA is applied to the image that contains the entire visible spectrum and is compared with previous results. Through the results of the four visible spectral images one can begin to draw conclusions about constituent painting materials without using decorrelation techniques.

Visual responses of pulvinar and collicular neurons during eye movements of awake, trained macaques

1991 ◽  
Vol 66 (2) ◽  
pp. 485-496 ◽  
Author(s):  
D. L. Robinson ◽  
J. W. McClurkin ◽  
C. Kertzman ◽  
S. E. Petersen
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Visual Responses ◽  
Stimulus Motion ◽  
Stimulus Movement ◽  
Pursuit Eye Movements ◽  
Extraretinal Signal ◽  
Wide Range

1. We recorded from single neurons in awake, trained rhesus monkeys in a lighted environment and compared responses to stimulus movement during periods of fixation with those to motion caused by saccadic or pursuit eye movements. Neurons in the inferior pulvinar (PI), lateral pulvinar (PL), and superior colliculus were tested. 2. Cells in PI and PL respond to stimulus movement over a wide range of speeds. Some of these cells do not respond to comparable stimulus motion, or discharge only weakly, when it is generated by saccadic or pursuit eye movements. Other neurons respond equivalently to both types of motion. Cells in the superficial layers of the superior colliculus have similar properties to those in PI and PL. 3. When tested in the dark to reduce visual stimulation from the background, cells in PI and PL still do not respond to motion generated by eye movements. Some of these cells have a suppression of activity after saccadic eye movements made in total darkness. These data suggest that an extraretinal signal suppresses responses to visual stimuli during eye movements. 4. The suppression of responses to stimuli during eye movements is not an absolute effect. Images brighter than 2.0 log units above background illumination evoke responses from cells in PI and PL. The suppression appears stronger in the superior colliculus than in PI and PL. 5. These experiments demonstrate that many cells in PI and PL have a suppression of their responses to stimuli that cross their receptive fields during eye movements. These cells are probably suppressed by an extraretinal signal. Comparable effects are present in the superficial layers of the superior colliculus. These properties in PI and PL may reflect the function of the ascending tectopulvinar system.

scholarly journals Eye-centered visual receptive fields in the ventral intraparietal area

2014 ◽  
Vol 112 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Xiaodong Chen ◽  
Gregory C. DeAngelis ◽  
Dora E. Angelaki
Keyword(s):  
Optic Flow ◽  
Reference Frames ◽  
Visual Stimulation ◽  
Receptive Fields ◽  
Large Field ◽  
Visual Responses ◽  
Full Field ◽  
Spatial Reference Frames ◽  
Visual Receptive Fields ◽  
Ventral Intraparietal Area

The ventral intraparietal area (VIP) processes multisensory visual, vestibular, tactile, and auditory signals in diverse reference frames. We recently reported that visual heading signals in VIP are represented in an approximately eye-centered reference frame when measured using large-field optic flow stimuli. No VIP neuron was found to have head-centered visual heading tuning, and only a small proportion of cells had reference frames that were intermediate between eye- and head-centered. In contrast, previous studies using moving bar stimuli have reported that visual receptive fields (RFs) in VIP are head-centered for a substantial proportion of neurons. To examine whether these differences in previous findings might be due to the neuronal property examined (heading tuning vs. RF measurements) or the type of visual stimulus used (full-field optic flow vs. a single moving bar), we have quantitatively mapped visual RFs of VIP neurons using a large-field, multipatch, random-dot motion stimulus. By varying eye position relative to the head, we tested whether visual RFs in VIP are represented in head- or eye-centered reference frames. We found that the vast majority of VIP neurons have eye-centered RFs with only a single neuron classified as head-centered and a small minority classified as intermediate between eye- and head-centered. Our findings suggest that the spatial reference frames of visual responses in VIP may depend on the visual stimulation conditions used to measure RFs and might also be influenced by how attention is allocated during stimulus presentation.

The Research on Special Printing Effects Based on Gray Component Replacement

2010 ◽  
Vol 174 ◽  
pp. 251-254 ◽  
Author(s):  
Ming Zheng Zhu ◽  
Zhe Chen ◽  
Hao Xue Liu
Keyword(s):  
Visible Light ◽  
Spectral Response ◽  
Response Properties ◽  
Digital Printer ◽  
Gray Component Replacement ◽  
Component Replacement

The data of CMY ink’s gray balance are got to define the replacement relationship between CMY and K ink by experiment with the digital printer. A special image was got by using CMY and K ink according to the principle of Gray Component Replacement (GCR).The image will have two different appearances by using the spectral response properties of CMY and K ink under visible light and infrared light．This kind of image can achieve the purpose of anti-counterfeiting printing.

The functional influence of nicotinic cholinergic receptors on the visual responses of neurones in the superficial superior colliculus

2000 ◽  
Vol 17 (2) ◽  
pp. 283-289 ◽  
Author(s):  
K.E. BINNS ◽  
T.E. SALT
Keyword(s):  
Superior Colliculus ◽  
Nicotinic Receptors ◽  
Visual Stimulation ◽  
Glutamate Release ◽  
Drug Application ◽  
Receptor Activation ◽  
Visual Input ◽  
Visual Response ◽  
Visual Responses ◽  
Parabigeminal Nucleus

In the rat, the superficial gray layer (SGS) of the superior colliculus receives glutamatergic projections from the contralateral retina and from the visual cortex. A few fibers from the ipsilateral retina also directly innervate the SGS, but most of the ipsilateral visual input is provided by cholinergic afferents from the opposing parabigeminal nucleus (PBG). Thus, visual input carried by cholinergic afferents may have a functional influence on the responses of SGS neurones. When single neuronal extracellular recording and iontophoretic drug application were employed to examine this possibility, cholinergic agonists were found to depress responses to visual stimulation. Lobeline and 1-acetyl-4-methylpiperazine both depressed visually evoked activity and had a tendency to reduce the background firing rate of the neurones. Carbachol depressed the visual responses without any significant effect on the ongoing activity, while the muscarinic receptor selective agonist methacholine increased the background activity of the neurones and reduced their visual responses. Lobeline was chosen for further studies on the role of nicotinic receptors in SGS. Given that nicotinic receptors are associated with retinal terminals in SGS, and that the activation of presynaptic nicotinic receptors normally facilitates transmitter release (in this case glutamate release), the depressant effects of nicotinic agonists are intriguing. However, many retinal afferents contact inhibitory neurones in SGS; thus it is possible that the increase in glutamate release in turn facilitates the liberation of GABA which goes on to inhibit the visual responses. We therefore attempted to reverse the effects of lobeline with GABA receptor antagonists. The depressant effects of lobeline on the visual response could not be reversed by the GABAA antagonist bicuculline, but the GABAB antagonist CGP 35348 reduced the effects of lobeline. We hypothesize that cholinergic drive from the parabigeminal nucleus may activate presynaptic nicotinic receptors on retinal terminals, thereby facilitating the release of glutamate onto inhibitory neurones. Consequently GABA is released, activating GABAB receptors, and thus the ultimate effect of nicotinic receptor activation is to depress visual responses.

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