Visual short-term memory for crossed and uncrossed binocular disparities.

Previous work on visual short-term memory (VSTM) has encompassed various stimulus attributes including spatial frequency, color, and contrast, revealing specific time courses and a dependence on stimulus parameters. This study investigates visual short-term memory for binocular depth, using dynamic random dot stereograms (DRDS) featuring disparity planes in front of or behind the plane of fixation. In a delayed match-to-sample paradigm, we employed four distinct reference disparities (17.

Artificial intelligence-based screening for amblyopia and its risk factors: comparison with four classic stereovision tests.

Introduction: The development of costs-effective and sensitive screening solutions to prevent amblyopia and identify its risk factors (strabismus, refractive problems or mixed) is a significant priority of pediatric ophthalmology. The main objective of our study was to compare the classification performance of various vision screening tests, including classic, stereoacuity-based tests (Lang II, TNO, Stereo Fly, and Frisby), and non-stereoacuity-based, low-density static, dynamic, and noisy anaglyphic random dot stereograms. We determined whether the combination of non-stereoacuity-based tests integrated in the simplest artificial intelligence (AI) model could be an alternative method for vision screening.

TRPM4 regulates hilar mossy cell loss in temporal lobe epilepsy.

Background: Mossy cells comprise a large fraction of excitatory neurons in the hippocampal dentate gyrus, and their loss is one of the major hallmarks of temporal lobe epilepsy (TLE). The vulnerability of mossy cells in TLE is well known in animal models as well as in patients; however, the mechanisms leading to cellular death is unclear.

Results: Transient receptor potential melastatin 4 (TRPM4) is a Ca-activated non-selective cation channel regulating diverse physiological functions of excitable cells.

Regional Variation of Gap Junctional Connections in the Mammalian Inner Retina.

The retinas of many species show regional specialisations that are evident in the differences in the processing of visual input from different parts of the visual field. Regional specialisation is thought to reflect an adaptation to the natural visual environment, optical constraints, and lifestyle of the species. Yet, little is known about regional differences in synaptic circuitry.

Calibration of random dot stereograms and correlograms free of monocular cues.

Dynamic random dot stereograms (DRDSs) and correlograms (DRDCs) are cyclopean stimuli containing binocular depth cues that are ideally, invisible by one eye alone. Thus, they are important tools in assessing stereoscopic function in experimental or ophthalmological diagnostic settings. However, widely used filter-based three-dimensional display technologies often cannot guarantee complete separation of the images intended for the two eyes.

Connexin-36 distribution and layer-specific topography in the cat retina.

Connexin-36 (Cx36) is the major constituent of mammalian retinal gap junctions positioned in key signal pathways. Here, we examined the laminar and large-scale topographical distribution of Cx36 punctate immunolabels in the retina of the cat, a classical model of the mammalian visual system. Calretinin-immunoreactive (CaR-IR) cell populations served to outline the nuclear and plexiform layers and to stain specific neuronal populations.

Correction: Simple reaction times to cyclopean stimuli reveal that the binocular system is tuned to react faster to near than to far objects.

[This corrects the article DOI: 10.1371/journal.pone.

Projections of three subcortical visual centers to marmoset lateral geniculate nucleus.

The dorsal lateral geniculate nucleus receives projections from visuotopically organized subcortical nuclei, in addition to inputs from the retina, visual cortices, and the thalamic reticular nucleus. Here, we study subcortical projections to the geniculate from the superior colliculus (SC) and parabigeminal nucleus (PBG) in the midbrain, and the nucleus of the optic tract (NOT) in the pretectum of marmosets. Marmosets are New World diurnal foveate monkeys, and are an increasingly popular model for studying the primate visual system.

Simple reaction times to cyclopean stimuli reveal that the binocular system is tuned to react faster to near than to far objects.

Binocular depth perception is an important mechanism to segregate the visual scene for mapping relevant objects in our environment. Convergent evidence from psychophysical and neurophysiological studies have revealed asymmetries between the processing of near (crossed) and far (uncrossed) binocular disparities. The aim of the present study was to test if near or far objects are processed faster and with higher contrast sensitivity in the visual system.

Temporal properties of colour opponent receptive fields in the cat lateral geniculate nucleus.

The primordial form of mammalian colour vision relies on opponent interactions between inputs from just two cone types, 'blue' (S-) and 'green' (ML-) cones. We recently described the spatial receptive field structure of colour opponent blue-ON cells from the lateral geniculate nucleus of cats. Functional inputs from the opponent cone types were spatially coextensive and equally weighted, supporting their high chromatic and low achromatic sensitivity.

Identification of a pathway from the retina to koniocellular layer K1 in the lateral geniculate nucleus of marmoset.

Three well characterized pathways in primate vision (midget-parvocellular, parasol-magnocellular, bistratified-koniocellular) have been traced from the first synapse in the retina, through the visual thalamus (lateral geniculate nucleus, LGN), to the visual cortex. Here we identify a pathway from the first synapse in the retina to koniocellular layer K1 in marmoset monkeys (Callithrix jacchus). Particle-mediated gene transfer of an expression plasmid for the postsynaptic density 95-green fluorescent protein (PSD95-GFP) was used to label excitatory synapses on retinal ganglion cells and combined with immunofluorescence to identify the presynaptic bipolar cells.

Receptive field properties of color opponent neurons in the cat lateral geniculate nucleus.

Most nonprimate mammals possess dichromatic ("red-green color blind") color vision based on short-wavelength-sensitive (S) and medium/long-wavelength-sensitive (ML) cone photoreceptor classes. However, the neural pathways carrying signals underlying the primitive "blue-yellow" axis of color vision in nonprimate mammals are largely unexplored. Here, we have characterized a population of color opponent (blue-ON) cells in recordings from the dorsal lateral geniculate nucleus of anesthetized cats.

Transmission of colour and acuity signals by parvocellular cells in marmoset monkeys.

The red-green axis of colour vision evolved recently in primate evolutionary history. Signals serving red-green colour vision travel together with signals serving spatial vision, in the parvocellular (PC) division of the subcortical visual pathway. However, the question of whether receptive fields of PC pathway cells are specialized to transmit red-green colour signals remains unresolved.

Neocortical axon arbors trade-off material and conduction delay conservation.

The brain contains a complex network of axons rapidly communicating information between billions of synaptically connected neurons. The morphology of individual axons, therefore, defines the course of information flow within the brain. More than a century ago, Ramón y Cajal proposed that conservation laws to save material (wire) length and limit conduction delay regulate the design of individual axon arbors in cerebral cortex.

Color signals in the primary visual cortex of marmosets.

This study concerns the input from short-wavelength sensitive (S) cone photoreceptors to the primary visual cortex (striate cortex, Brodmann area 17, area V1) in marmosets. Signals from S-cones are thought to reach V1 by way of the koniocellular layers of the dorsal lateral geniculate nucleus. However, it is not known whether the S-cone afferent signals cause selective activation of cytochrome oxidase-rich cortical "blob" domains.

Geniculocortical relay of blue-off signals in the primate visual system.

A fundamental dichotomy in the subcortical visual system exists between on- and off-type neurons, which respectively signal increases and decreases of light intensity in the visual environment. In primates, signals for red-green color vision are carried by both on- and off-type neurons in the parvocellular division of the subcortical pathway. It is thought that on-type signals for blue-yellow color vision are carried by cells in a distinct, diffusely projecting (koniocellular) pathway, but the pathway taken by blue-off signals is not known.

Model-based analysis of excitatory lateral connections in the visual cortex.

Excitatory lateral connections within the primary visual cortex are thought to link neurons with similar receptive field properties. Here we studied whether this rule can predict the distribution of excitatory connections in relation to cortical location and orientation preference in the cat visual cortex. To this end, we obtained orientation maps of areas 17 or 18 using optical imaging and injected anatomical tracers into these regions.

Specificity of M and L cone inputs to receptive fields in the parvocellular pathway: random wiring with functional bias.

Many of the parvocellular pathway (PC) cells in primates show red-green spectral selectivity (cone opponency), but PC ganglion cells in the retina show no anatomical signs of cone selectivity. Here we asked whether responses of PC cells are compatible with "random wiring" of cone inputs. We measured long-wavelength-sensitive (L) and medium-wavelength-sensitive (M) cone inputs to PC receptive fields in the dorsal lateral geniculate of marmosets, using discrete stimuli (apertures and annuli) to achieve functional segregation of center and surround.

Contribution of chromatic aberrations to color signals in the primate visual system.

We measured responses to red-green color variation in parvocellular (PC) neurons in the lateral geniculate nucleus of dichromatic ("red-green color blind") marmoset monkeys. Although these animals lack distinct visual pigments to distinguish between wavelengths in this range, many of the colored stimuli nevertheless produced robust responses in PC cells. We show that these responses, which are restricted to high stimulus spatial frequencies (fine image details), arise from chromatic aberrations in the eye.

Independence of visuotopic representation and orientation map in the visual cortex of the cat.

The representations of visual space and stimulus orientation were mapped in the cat primary visual cortex using electrophysiological recordings supplemented with intrinsic signal optical imaging. The majority of units displaced up to 600 micro m laterally had overlapping RFs both in orientation domains and around singularities of the orientation map. Quantitative comparison of these units revealed only a weak, positive correlation between the difference in their preferred orientations and RF separations (area 17: r = 0.

One axon-multiple functions: specificity of lateral inhibitory connections by large basket cells.

The functional specificity of the projections of single large basket cells of the cat primary visual cortex was studied using novel analytical approaches. The distribution of the labelled axons and that of the target cells were three-dimensionally reconstructed and compared quantitatively to orientation, direction and ocular dominance maps obtained with the intrinsic signal optical imaging technique. Quantitative analysis was carried out (i) for the entire basket cell, (ii) separately, for local and distal projections of the axon and (iii) by dissecting the same axon into two projection fields at the first bifurcation.