Polarization vision – a uniform sensory capacity?

2001 ◽  
Vol 204 (14) ◽  
pp. 2589-2596 ◽  
Author(s):  
Rüdiger Wehner
Keyword(s):  
Polarized Light ◽  
Neural Mechanisms ◽  
Degree Of Polarization ◽  
Polarization Vision ◽  
Terrestrial Habitat ◽  
Spectral Content ◽  
Common Receptor ◽  
Sensory Capacity ◽  
Different Types ◽  
Processing Mechanisms

SUMMARYIn this concept paper, three scenarios are described in which animals make use of polarized light: the underwater world, the water surface and the terrestrial habitat vaulted by the pattern of polarized light in the sky. Within these various visual environments, polarized light is used in a number of ways that make quite different demands on the neural circuitries mediating these different types of behaviour. Apart from some common receptor and pre-processing mechanisms, the underlying neural mechanisms may differ accordingly. Often, information about χ (the angle of polarization), d (the degree of polarization) and λ (the spectral content) might not – and need not – be disentangled. Hence, the hypothesis entertained in this account is that polarization vision comes in various guises, and that the answer to the question posed in the title is most probably no.

Motion Perception in Autism: A “Complex” Issue

2003 ◽  
Vol 15 (2) ◽  
pp. 218-225 ◽  
Author(s):  
Armando Bertone ◽  
Laurent Mottron ◽  
Patricia Jelenic ◽  
Jocelyn Faubert
Keyword(s):  
Neural Mechanisms ◽  
Neural Processing ◽  
Perceptual Integration ◽  
Complex Issue ◽  
Motion Patterns ◽  
Motion Sensitivity ◽  
First Order ◽  
Cognitive Operations ◽  
Different Types ◽  
Processing Mechanisms

We present the first assessment of motion sensitivity for persons with autism and normal intelligence using motion patterns that require neural processing mechanisms of varying complexity. Compared to matched controls, our results demonstrate that the motion sensitivity of observers with autism is similar to that of nonautistic observers for different types of first-order (luminance-defined) motion stimuli, but significantly decreased for the same types of second-order (texture-defined) stimuli. The latter class of motion stimuli has been demonstrated to require additional neural computation to be processed adequately. This finding may reflect less efficient integrative functioning of the neural mechanisms that mediate visuoperceptual processing in autism. The contribution of this finding with regards to abnormal perceptual integration in autism, its effect on cognitive operations, and possible behavioral implications are discussed.

scholarly journals Ultraviolet polarization vision in fishes: possible mechanisms for coding e–vector

2000 ◽  
Vol 355 (1401) ◽  
pp. 1187-1190 ◽  
Author(s):  
Craig W. Hawryshyn
Keyword(s):  
Polarized Light ◽  
Spatial Arrangement ◽  
Short Review ◽  
Research Problem ◽  
Polarization Sensitivity ◽  
Polarization Vision ◽  
Selective Reflection ◽  
Mosaic Pattern ◽  
Cone Mosaic ◽  
Biophysical Mechanism

Polarization vision in vertebrates has been marked with significant controversy over recent decades. In the last decade, however, models from two laboratories have indicated that the spatial arrangement of photoreceptors provides the basis for polarization sensitivity.Work in my laboratory, in collaboration with I. Novales Flamarique and F. I. Harosi, has shown that polarization sensitivity depends on a well–defined square cone mosaic pattern and that the biophysical properties of the square cone mosaic probably account for polarization vision in the ultraviolet spectrum. The biophysical mechanism appears to be based on the selective reflection of axial–polarized light by the partitioning membrane, formed along the contact zone between the members of the double cones, onto neighbouring ultraviolet–sensitive cones. In this short review, I discuss the historical development of this research problem.

Different Types of Signal Coupling in the Visual Cortex Related to Neural Mechanisms of Associative Processing and Perception

2004 ◽  
Vol 15 (5) ◽  
pp. 1039-1052 ◽  
Author(s):  
R. Eckhorn ◽  
A.M. Gail ◽  
A. Bruns ◽  
A. Gabriel ◽  
B. Al-Shaikhli ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Neural Mechanisms ◽  
Associative Processing ◽  
Different Types

scholarly journals Polarization-based brightness discrimination in the foraging butterfly, Papilio xuthus

2011 ◽  
Vol 366 (1565) ◽  
pp. 688-696 ◽  
Author(s):  
Michiyo Kinoshita ◽  
Kei Yamazato ◽  
Kentaro Arikawa
Keyword(s):  
Light Intensity ◽  
Animal Species ◽  
Brightness Discrimination ◽  
Egg Laying ◽  
Polarization Vision ◽  
Discrimination Test ◽  
Spectral Content ◽  
Papilio Xuthus ◽  
Choice Tests ◽  
Vector Orientation

The human eye is insensitive to the angular direction of the light e-vector, but several animal species have the ability to discriminate differently polarized lights. How the polarization is detected is often unclear, however. Egg-laying Papilio butterflies have been shown to see false colours when presented with differently polarized lights. Here we asked whether this also holds in foraging butterflies. After training individuals to feed on nectar in front of an unpolarized spectral light, we carried out three dual-choice tests, where the discrimination of (i) the spectral content, (ii) the light intensity, and (iii) the e-vector orientation were investigated. In the first test, the butterflies selected the trained spectrum irrespective of its intensity, and in the second test they chose the light with the higher intensity. The result of the e-vector discrimination test was very similar to that of the second test, suggesting that foraging butterflies discriminate differently polarized lights as differing in brightness rather than as differing in colour. Papilio butterflies are clearly able to use at least two modes of polarization vision depending on the behavioural context.

Distinct profiles of stimulus specific cortical activity for ignoring distraction during working memory encoding and maintenance, and associations with performance

2020 ◽  
Author(s):  
Charlotte Ashton ◽  
André Gouws ◽  
Marcus Glennon ◽  
THEODORE ZANTO ◽  
Steve Tipper ◽  
...  
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Relevant Information ◽  
Cortical Activity ◽  
Irrelevant Information ◽  
Neural Mechanisms ◽  
Memory Encoding ◽  
Different Types ◽  
Short Time

Abstract Our ability to hold information in mind for a short time (working memory) is separately predicted by our ability to ignore two types of distraction: distraction that occurs while we put information into working memory (encoding) and distraction that occurs while we maintain already encoded information within working memory. This suggests that ignoring these different types of distraction involves distinct mechanisms which separately limit performance. Here we used fMRI to measure category-sensitive cortical activity and probe these mechanisms. The results reveal specific neural mechanisms by which relevant information is remembered and irrelevant information is ignored, which contribute to intra-individual differences in WM performance.

scholarly journals Demonstration of polarization control GaN-based micro-cavity lasers using a rigid high-contrast grating reflector

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tsu-Chi Chang ◽  
Kuo-Bin Hong ◽  
Shuo-Yi Kuo ◽  
Tien-Chang Lu
Keyword(s):  
Semiconductor Lasers ◽  
Optical Pumping ◽  
Polarized Light ◽  
Transverse Magnetic ◽  
Bragg Reflector ◽  
Degree Of Polarization ◽  
High Contrast ◽  
Distributed Bragg Reflector ◽  
Output Mirror ◽  
High Contrast Grating

Abstract We reported on GaN microcavity (MC) lasers combined with one rigid TiO2 high-contrast grating (HCG) structure as the output mirror. The HCG structure was directly fabricated on the GaN structure without an airgap. The entire MC structure comprised a bottom dielectric distributed Bragg reflector; a GaN cavity; and a top HCG reflector, which was designed to yield high reflectance for transverse magnetic (TM)- or transverse electric (TE)-polarized light. The MC device revealed an operation threshold of approximately 0.79 MW/cm2 when pulsed optical pumping was conducted using the HCG structure at room temperature. The laser emission was TM polarized with a degree of polarization of 99.2% and had a small divergence angle of 14° (full width at half maximum). This laser operation demonstration for the GaN-based MC structure employing an HCG exhibited the advantages of HCGs in semiconductor lasers at wavelengths from green to ultraviolet.

scholarly journals Polarized proton beams from laser-induced plasmas

2019 ◽  
Vol 7 ◽  
Author(s):  
Anna Hützen ◽  
Johannes Thomas ◽  
Jürgen Böker ◽  
Ralf Engels ◽  
Ralf Gebel ◽  
...  
Keyword(s):  
Laser System ◽  
Polarized Light ◽  
Particle Beam ◽  
Degree Of Polarization ◽  
Acceleration Process ◽  
Simulation Code ◽  
Experimental Realization ◽  
Circularly Polarized Light ◽  
Spin Effects ◽  
Polarized Proton

We report on the concept of an innovative source to produce polarized proton/deuteron beams of a kinetic energy up to several GeV from a laser-driven plasma accelerator. Spin effects have been implemented into the particle-in-cell (PIC) simulation code VLPL (Virtual Laser Plasma Lab) to make theoretical predictions about the behavior of proton spins in laser-induced plasmas. Simulations of spin-polarized targets show that the polarization is conserved during the acceleration process. For the experimental realization, a polarized HCl gas-jet target is under construction using the fundamental wavelength of a Nd:YAG laser system to align the HCl bonds and simultaneously circularly polarized light of the fifth harmonic to photo-dissociate, yielding nuclear polarized H atoms. Subsequently, their degree of polarization is measured with a Lamb-shift polarimeter. The final experiments, aiming at the first observation of a polarized particle beam from laser-generated plasmas, will be carried out at the 10 PW laser system SULF at SIOM, Shanghai.

Optical Pumping and Optical Detection of Spin-Polarized Electrons in a Conduction Band

1971 ◽  
Vol 49 (14) ◽  
pp. 1850-1860 ◽  
Author(s):  
R. R. Parsons
Keyword(s):  
Magnetic Field ◽  
Conduction Band ◽  
Spin Polarization ◽  
Optical Pumping ◽  
Polarized Light ◽  
Degree Of Polarization ◽  
Polarized Electrons ◽  
Excitation Light ◽  
Circularly Polarized Light ◽  
Spin Polarized

Spin-polarized electrons are created in the conduction band of p-type GaSb by excitation with σ+ or σ− circularly polarized light. The degree of polarization of the photoluminescence is used to measure the optically pumped spin polarization. The measurements as a function of transverse magnetic field yield the spin-relaxation time and the lifetime of the photocreated electrons. The degree of polarization oscillates as a function of the photon energy of the excitation light. This effect is associated with mechanisms of rapid energy loss involving optical and acoustical phonons. The optical pumping is studied as a function of temperature in the range 3.5 °K ≤ T ≤ 11 °K. A maximum spin polarization [Formula: see text] is obtained at [Formula: see text]. The efficiency of the optical pumping is significantly increased with the application of a weak longitudinal magnetic field.

Interfacial Electronic Scattering in Fe/Cr Superlattices

2014 ◽  
Vol 215 ◽  
pp. 331-336
Author(s):  
Ivan D. Lobov ◽  
Margarita M. Kirillova ◽  
Lazar N. Romashev ◽  
Mikhail A. Milyaev ◽  
Vladimir V. Ustinov
Keyword(s):  
Exchange Coupling ◽  
Polarized Light ◽  
Scattering Parameters ◽  
Multilayered Structures ◽  
Different Types ◽  
Infrared Spectral ◽  
Spin Dependent Scattering ◽  
Interfacial Scattering ◽  
Electronic Scattering ◽  
Magnetorefractive Effect

The magnetorefractive effect (MRE) has been measured in the infrared spectral region of 1.2-28 μm in MBE-grown Fe/Cr superlattices with variable Fe and Cr layers thicknesses inp-polarized light. The magnetic and magnetooptical properties have been studied as well. From the MRE spectra modeling in the framework of magnetoreflection theory for multilayered structures, the parameters of interfacial spin dependent scattering of conductivity electrons have been defined for different types of exchange coupling between adjacent Fe layers. The dependence of interfacial scattering parameters on Fe and Cr layer thickness is discussed.

The fine structure of uniporous and nonporous pegs on the distal antennal segment of the diving beetle Graphoderus occidentalis Horn (Coleoptera: Dytiscidae)

1991 ◽  
Vol 69 (2) ◽  
pp. 334-352 ◽  
Author(s):  
J. C. Jensen ◽  
R. Y. Zacharuk
Keyword(s):  
Fine Structure ◽  
Antennal Segment ◽  
Terminal Segment ◽  
Sheath Cell ◽  
Terrestrial Habitat ◽  
Insect Sensilla ◽  
Virus Like Particles ◽  
Accessory Cells ◽  
Different Types ◽  
Diving Beetle

The terminal segment of the antenna of the predaceous diving beetle Graphoderus occidentalis Horn bears approximately 50 sensilla of nine different types. There are six types of uniporous chemosensilla, one type of nonporous mechanosensitive peg, and two types of multiporous pegs. Two types of uniporous pegs, which occur only at the antennal tip, have features of both contact chemosensilla and thermo- and hygro-sensilla. Three other types that occur only on the terminal segment below the apex also exhibit some features of chemosensilla and thermo- and hygro-sensilla. The sensilla are innervated by one to four neurons and most are ensheathed by two accessory cells. Four types of sensilla exhibit elaborate sheath cell configurations and secretions associated with their sinus that may reflect an adaptation to an aquatic or a dual aquatic–terrestrial habitat. All are atypical of generalized insect sensilla in having portions of the proximal dendrites and axons as well as the entire neuronal perikarya unsheathed and exposed to the hemocoel. The neuronal perikarya of two sensillar types contain virus-like particles.

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