Central Processing Of Visual Information Research Articles

Movement-Dependent Spatial Expansion of Visual Receptive Fields of Neurons of the Extrastriate Cortex

The spatial structure of the receptive field (RF) of a visually sensitive neuron, as defined by presentation of stationary visual stimuli, predetermines in most cases central processing of visual information concerning moving visual images. In our study, properties of a group of neurons in the extrastriate cortical area 21a (≈18% of the examined sampling) with extremely small RF sizes (≈1.5 deg2) determined by stationary visual stimuli were investigated. It was found that spatial dimensions of each neuronal RFs may undergo manifold expansions; the neuronal response profiles depended strongly on the size, shape, and contrast of the applied moving stimuli. As a result, a high degree of diversification of neuronal response patterns depending of the shapes and contrasts of applied moving stimuli was observed. These data confirm the suggestion that the RFs of neurons in the extrastriate area 21a undergo temporary dynamic changes due to activation of surrounding neuronal groups/networks by moving visual stimuli. Thus, it is evident that processing of visual information in the course of visual image recognition is realized by integrated activity of a complex of the corresponding cortical networks of visually sensitive neurons.

Segregation of visual inputs from different regions of the compound eye in two parallel pathways through the anterior optic tubercle of the bumblebee (Bombus ignitus)

AbstractVisually guided behaviors require the brain to extract features of the visual world and to integrate them in a context‐specific manner. Hymenopteran insects have been prime models for ethological research into visual behaviors for decades but knowledge about the underlying central processing is very limited. This is particularly the case for sky‐compass navigation. To learn more about central processing of visual information in general and specifically to reveal a possible polarization vision pathway in the bee brain, we used tracer injections to investigate the pathways through the anterior optic tubercle, a prominent output target of the insect optic lobe, in the bumblebee Bombus ignitus. The anterior optic tubercle of the bumblebee is a small neuropil of 200 μm width and is located dorsolateral to the antennal lobe at the anterior surface of the brain. It is divided into a larger upper and a smaller lower subunit, both of which receive input from the optic lobe and connect to the lateral accessory lobe, and the contralateral tubercle, via two parallel pathways. The lower subunit receives input from the dorsal rim area (DRA) of the compound eye. The bumblebee DRA shares structural similarities with polarization‐sensitive DRAs of other insects and looks similar to that of honeybees. We identified several neurons within this pathway that could be homologous to identified polarization‐sensitive neurons in the locust brain. We therefore conclude that the pathway through the lower subunit of the anterior optic tubercle could carry polarization information from the periphery to the central brain. J. Comp. Neurol. 520:212–229, 2012. © 2011 Wiley Periodicals, Inc.

Segregation of visual inputs from different regions of the compound eye in two parallel pathways through the anterior optic tubercle of the bumblebee (Bombus ignitus)

Visually guided behaviors require the brain to extract features of the visual world and to integrate them in a context-specific manner. Hymenopteran insects have been prime models for ethological research into visual behaviors for decades but knowledge about the underlying central processing is very limited. This is particularly the case for sky-compass navigation. To learn more about central processing of visual information in general and specifically to reveal a possible polarization vision pathway in the bee brain, we used tracer injections to investigate the pathways through the anterior optic tubercle, a prominent output target of the insect optic lobe, in the bumblebee Bombus ignitus. The anterior optic tubercle of the bumblebee is a small neuropil of 200 μm width and is located dorsolateral to the antennal lobe at the anterior surface of the brain. It is divided into a larger upper and a smaller lower subunit, both of which receive input from the optic lobe and connect to the lateral accessory lobe, and the contralateral tubercle, via two parallel pathways. The lower subunit receives input from the dorsal rim area (DRA) of the compound eye. The bumblebee DRA shares structural similarities with polarization-sensitive DRAs of other insects and looks similar to that of honeybees. We identified several neurons within this pathway that could be homologous to identified polarization-sensitive neurons in the locust brain. We therefore conclude that the pathway through the lower subunit of the anterior optic tubercle could carry polarization information from the periphery to the central brain.

Precision and accuracy of the subjective haptic vertical in the roll plane

BackgroundWhen roll-tilted, the subjective visual vertical (SVV) deviates up to 40° from earth-vertical and trial-to-trial variability increases with head roll. Imperfections in the central processing of visual information were postulated to explain these roll-angle dependent errors. For experimental conditions devoid of visual input, e.g. adjustments of body posture or of an object along vertical in darkness, significantly smaller errors were noted. Whereas the accuracy of verticality adjustments seems to depend strongly on the paradigm, we hypothesize that the precision, i.e. the inverse of trial-to-trial variability, is less influenced by the experimental setup and mainly reflects properties of the otoliths. Here we measured the subjective haptic vertical (SHV) and compared findings with previously reported SVV data. Twelve healthy right-handed human subjects (handedness assessed based on subjects' verbal report) adjusted a rod with the right hand along perceived earth-vertical during static head roll-tilts (0-360°, steps of 20°).ResultsSHV adjustments showed a tendency for clockwise rod rotations to deviate counter-clockwise and for counter-clockwise rod rotations to deviate clockwise, indicating hysteresis. Clockwise rod rotations resulted in counter-clockwise shifts of perceived earth-vertical up to -11.7° and an average counter-clockwise SHV shift over all roll angles of -3.3° (± 11.0°; ± 1 StdDev). Counter-clockwise rod rotations yielded peak SHV deviations in clockwise direction of 8.9° and an average clockwise SHV shift over all roll angles of 1.8° (± 11.1°). Trial-to-trial variability was minimal in upright position, increased with increasing roll (peaking around 120-140°) and decreased to intermediate values in upside-down orientation. Compared to SVV, SHV variability near upright and upside-down was non-significantly (p > 0.05) larger; both showed an m-shaped pattern of variability as a function of roll position.ConclusionsThe reduction of adjustment errors by eliminating visual input supports the notion that deviations between perceived and actual earth-vertical in roll-tilted positions arise from central processing of visual information. The shared roll-tilt dependent modulation of trial-to-trial variability for both SVV and SHV, on the other hand, indicates that the perception of earth-verticality is dominated by the same sensory signal, i.e. the otolith signal, independent of whether the line/rod setting is under visual or tactile control.

Cellular distributions and functions of histamine, octopamine, and serotonin in the peripheral visual system, brain, and circumesophageal ring of the horseshoe crab Limulus polyphemus.

The data reviewed here show that histamine, octopamine, and serotonin are abundant in the visual system of the horseshoe crab Limulus polyphemus. Anatomical and biochemical evidence, including new biochemical data presented here, indicates that histamine is a neurotransmitter in primary retinal afferents, and that it may be involved in visual information processing within the lateral eye. The presence of histamine in neurons of the central nervous system outside of the visual centers suggests that this amine also has functions unrelated to vision. However, the physiological actions of histamine in the Limulus nervous system are not yet known. Octopamine is present in and released from the axons of neurons that transmit circadian information from the brain to the eyes, and octopamine mimics the actions of circadian input on many retinal functions. In addition, octopamine probably has major functions in other parts of the nervous system as octopamine immunoreactive processes are widely distributed in the central nervous system and in peripheral motor nerves. Indeed, octopamine modulates functions of the heart and exoskeletal muscles as well as the eyes. A surprising finding is that although octopamine is a circulating neurohormone in Limulus, there is no structural evidence for its release into the hemolymph from central sites. The distribution of serotonin in Limulus brain suggests this amine modulates the central processing of visual information. Serotonin modulates cholinergic synapses in the central nervous system, but nothing further is known about its physiological actions.

Objective assessment of central processing of visual information by means of pupillometry

Objective assessment of central processing of visual information by means of pupillometry

Sex Differences in the Perception of Autokinetic Movement of an afterimage

The effects of stimulus color and gender upon the perception of an afterimage were examined. The Ss were 32 male and 32 female college undergraduate volunteers. Eight Ss of each gender viewed a pinpoint flash of light through one of four filters: blue-green (Wratten 44A), red (Wratten 92), yellow (Wratten 9), or a neutral (Wratten 96) filter. Each S was given three trials, and on each trial, the duration of the afterimage was recorded, along with changes of direction, and changes in perceived color. Males reported significantly (p less than .05) more autokinetic movement of the afterimage. The color of the stimulus affected afterimage duration differentially for the two genders (p less than .05), and there was also a significant interaction (p less than .02) of gender with filter color for the total number of color changes reported. Thus, it is likely that both outflow monitoring and error signal variables in the autokinetic effect may be affected by gender, and the two sexes may also have different retinal and/or central processing of visual information.

Inferotemporal versus combined pulvinar-prestriate lesions in the rhesus monkey: Effects on color, object and pattern discrimination

Monkeys with inferotemporal lesions were compared to monkeys with combined lesions of the pulvinar and prestriate cortex on discrimination problems and on tests of sensory function. Inferotemporal lesions severely impaired discrimination of colors, objects, and patterns, but did not produce any sensory loss. By contrast, combined pulvinar-prestriate lesions impaired only discrimination of patterns, an impairment associated with sensory deficits and with degeneration of the lateral geniculate nucleus. Thus, inferotemporal lesions affected visual discriminations per se, whereas combined pulvinar-prestriate lesions affected discriminations related to specific dimensions of visual stimuli. These qualitatively different effects of inferotemporal and combined pulvinar-prestriate lesions are discussed in terms of current models of central processing of visual information.

Peripheral mechanisms of vision.

This r eview is concerned with r ecent studies1 o f the vert ebrate retina, particularly those reporting microelectrode investigations of unit responses and anatomical studies o f retinal cytoarchitecture and synapses. From thes e studi es has emerged a more precise appr eciation than pr eviously possibl e of th e rol e pl ay ed by a giv en n euron al r espons e in the functional organization of the r etina. Given the limitations o f space, emphasis o f one body o f inves­ tigations has precluded a thorough review o f oth ers. The readers' attention is drawn to recent reviews and symposia concerned with the visual sys­ tem (1-16), some of which summarize areas of research neglected in this essay. Of parti cula r interest is th e p ro jected Handbook of Sensory Physiol­ ogy series by Springe r, now in pr eparation . Volume V I I, nos . 1-4 will d eal with the visual syst em. The titl es ar e The photochemistry of vision, Physiol­ ogy of photoreceptor organs, Central processing of visual information, and Visual psychophysics.