scholarly journals Fruit flies increase attention to their frontal visual field during fast forward optic flow

2019 ◽  
Vol 15 (1) ◽  
pp. 20180767 ◽  
Author(s):  
Nicholas Palermo ◽  
Jamie Theobald
Keyword(s):  
Visual Field ◽  
Visual Attention ◽  
Flow Field ◽  
Optic Flow ◽  
Fruit Flies ◽  
Motion Blur ◽  
Image Motion ◽  
Forward Flight ◽  
Forward Motion ◽  
Visual Areas

Fruit flies must compensate for the limited light gathered by the tiny facets of their eyes, and image motion during flight lowers light catch even further. Motion blur is especially problematic in fast regions of the visual field, perpendicular to forward motion, but flow fields also contain slower regions, less affected by blur. To test whether fruit flies shift their attention to predictably slower regions of a flow field, we placed flies in an arena simulating forward flight and measured responses to turning cues in different visual areas. We find that during fast forward flight, fruit flies respond more strongly to turning cues presented directly in front, and less strongly to cues presented to the sides, supporting the hypothesis that flying fruit flies shift visual attention to slower moving regions less affected by motion blur.

Simulated Optic Flow and Extrastriate Cortex. I. Optic Flow Versus Texture

1997 ◽  
Vol 77 (2) ◽  
pp. 554-561 ◽  
Author(s):  
Jong-Nam Kim ◽  
Kathleen Mulligan ◽  
Helen Sherk
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Optic Flow ◽  
Visual Experience ◽  
Extrastriate Cortex ◽  
Gray Level ◽  
Visual Guidance ◽  
Forward Motion ◽  
Cell Responses ◽  
Single Origin

Kim, Jong-Nam, Kathleen Mulligan, and Helen Sherk. Simulated optic flow and extrastriate cortex. I. Optic flow versus texture. J. Neurophysiol. 77: 554–561, 1997. A locomoting observer sees a very different visual scene than an observer at rest: images throughout the visual field accelerate and expand, and they follow approximately radial outward paths from a single origin. This so-called optic flow field is presumably used for visual guidance, and it has been suggested that particular areas of visual cortex are specialized for the analysis of optic flow. In the cat, the lateral suprasylvian visual area (LS) is a likely candidate. To test the hypothesis that LS is specialized for analysis of optic flow fields, we recorded cell responses to optic flow displays. Stimulus movies simulated the experience of a cat trotting slowly across an endless plain covered with small balls. In different simulations we varied the size of balls, their organization (randomly or regularly dispersed), and their color (all one gray level, or multiple shades of gray). For each optic flow movie, a “texture” movie composed of the same elements but lacking optic flow cues was tested. In anesthetized cats, >500 neurons in LS were studied with a variety of movies. Most (70%) of 454 visually responsive cells responded to optic flow movies. Visually responsive cells generally preferred optic flow to texture movies (69% of those responsive to any movie). The direction in which a movie was shown (forward or reverse) was also an important factor. Most cells (68%) strongly preferred forward motion, which corresponded to visual experience during locomotion.

scholarly journals Dissociating Vision and Visual Attention in the Human Pulvinar

2009 ◽  
Vol 101 (2) ◽  
pp. 917-925 ◽  
Author(s):  
A. T. Smith ◽  
P. L. Cotton ◽  
A. Bruno ◽  
C. Moutsiana
Keyword(s):  
Visual Field ◽  
Visual Attention ◽  
Visual Stimulus ◽  
Optic Flow ◽  
Nonhuman Primates ◽  
Retinotopic Organization ◽  
Cortical Regions ◽  
Mri Study ◽  
Related Design ◽  
Central Fixation

The pulvinar region of the thalamus has repeatedly been linked with the control of attention. However, the functions of the pulvinar remain poorly characterized, both in human and in nonhuman primates. In a functional MRI study, we examined the relative contributions to activity in the human posterior pulvinar made by visual drive (the presence of an unattended visual stimulus) and attention (covert spatial attention to the stimulus). In an event-related design, large optic flow stimuli were presented to the left and/or right of a central fixation point. When unattended, the stimuli robustly activated two regions of the pulvinar, one medial and one dorsal with respect to the lateral geniculate. The activity in both regions shows a strong contralateral bias, suggesting retinotopic organization. Primate physiology suggests that the two regions could be two portions of the same double map of the visual field. In our paradigm, attending to the stimulus enhanced the response by about 20%. Thus attention is not necessary to activate the human pulvinar and the degree of attentional enhancement matches, but does not exceed, that seen in the cortical regions with which the posterior pulvinar connects.

scholarly journals Interactions of local movement detectors enhance the detection of rotation. Optokinetic experiments with the rock crab, Pachygrapsus marmoratus

1993 ◽  
Vol 10 (4) ◽  
pp. 643-652 ◽  
Author(s):  
Roland Kern ◽  
Hans-Ortwin Nalbach ◽  
Dezsö Varjú
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Optic Flow ◽  
Image Motion ◽  
Optokinetic Responses ◽  
Retinal Image Motion ◽  
Pachygrapsus Marmoratus ◽  
Movement Detectors ◽  
Local Movement ◽  
Rock Crab

AbstractWalking crabs move their eyes to compensate for retinal image motion only during rotation and not during translation, even when both components are superimposed. We tested in the rock crab, Pachygrapsus marmoratus, whether this ability to decompose optic flow may arise from topographical interactions of local movement detectors. We recorded the optokinetic eye movements of the rock crab in a sinusoidally oscillating drum which carried two 10-deg wide black vertical stripes. Their azimuthal separation varied from 20 to 180 deg, and each two-stripe configuration was presented at different azimuthal positions around the crab. In general, the responses are the stronger the more widely the stripes are separated. Furthermore, the response amplitude depends also strongly on the azimuthal positions of the stripes. We propose a model with excitatory interactions between pairs of movement detectors that quantitatively accounts for the enhanced optokinetic responses to widely separated textured patches in the visual field that move in phase. The interactions take place both within one eye and, predominantly, between both eyes. We conclude that these interactions aid in the detection of rotation.

scholarly journals To keep on track during flight, fruitflies discount the skyward view

2014 ◽  
Vol 10 (2) ◽  
pp. 20131103 ◽  
Author(s):  
Chantell Mazo ◽  
Jamie C. Theobald
Keyword(s):  
Flow Field ◽  
Rotational Motion ◽  
Optic Flow ◽  
Translational Motion ◽  
Visual Fields ◽  
Flow Fields ◽  
Motion Pattern ◽  
Flying Insects ◽  
Visual Areas ◽  
Pattern Of Motion

When small flying insects go off their intended course, they use the resulting pattern of motion on their eye, or optic flow, to guide corrective steering. A change in heading generates a unique, rotational motion pattern and a change in position generates a translational motion pattern, and each produces corrective responses in the wingbeats. Any image in the flow field can signal rotation, but owing to parallax, only the images of nearby objects can signal translation. Insects that fly near the ground might therefore respond more strongly to translational optic flow that occurs beneath them, as the nearby ground will produce strong optic flow. In these experiments, rigidly tethered fruitflies steered in response to computer-generated flow fields. When correcting for unintended rotations, flies weight the motion in their upper and lower visual fields equally. However, when correcting for unintended translations, flies weight the motion in the lower visual fields more strongly. These results are consistent with the interpretation that fruitflies stabilize by attending to visual areas likely to contain the strongest signals during natural flight conditions.

scholarly journals Through hawks' eyes: reconstructing a bird's visual field in flight to study gaze strategy and attention during perching and obstacle avoidance

2021 ◽  
Author(s):  
Sofia Minano ◽  
Graham K Taylor
Keyword(s):  
Visual Field ◽  
Visual Attention ◽  
Obstacle Avoidance ◽  
Motion Capture ◽  
Optic Flow ◽  
Visual Cues ◽  
Small Subset ◽  
Depth Information ◽  
Motion Capture Data ◽  
Full Dataset

We present a method to analyse visual attention of a bird in flight, that combines motion capture data with renderings from virtual cameras. We applied it to a small subset of a larger dataset of perching and obstacle avoidance manoeuvres, and studied visual field stabilisation and gaze shifts. Our approach allows us to synthesise visual cues available to the bird during flight, such as depth information and optic flow, which can lead to novel insights into the bird's gaze strategy in flight. This preliminary work demonstrates the method and suggests several new hypotheses to investigate with the full dataset.

scholarly journals Myelin densities in retinotopically defined dorsal visual areas of the macaque

2021 ◽  
Author(s):  
Xiaolian Li ◽  
Qi Zhu ◽  
Wim Vanduffel
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Cortical Thickness ◽  
New World Monkeys ◽  
Isotropic Resolution ◽  
Density Mapping ◽  
Area V2 ◽  
Visual Areas ◽  
Density Results

AbstractThe visuotopic organization of dorsal visual cortex rostral to area V2 in primates has been a longstanding source of controversy. Using sub-millimeter phase-encoded retinotopic fMRI mapping, we recently provided evidence for a surprisingly similar visuotopic organization in dorsal visual cortex of macaques compared to previously published maps in New world monkeys (Zhu and Vanduffel, Proc Natl Acad Sci USA 116:2306–2311, 2019). Although individual quadrant representations could be robustly delineated in that study, their grouping into hemifield representations remains a major challenge. Here, we combined in-vivo high-resolution myelin density mapping based on MR imaging (400 µm isotropic resolution) with fine-grained retinotopic fMRI to quantitatively compare myelin densities across retinotopically defined visual areas in macaques. Complementing previously documented differences in populational receptive-field (pRF) size and visual field signs, myelin densities of both quadrants of the dorsolateral posterior area (DLP) and area V3A are significantly different compared to dorsal and ventral area V3. Moreover, no differences in myelin density were observed between the two matching quadrants belonging to areas DLP, V3A, V1, V2 and V4, respectively. This was not the case, however, for the dorsal and ventral quadrants of area V3, which showed significant differences in MR-defined myelin densities, corroborating evidence of previous myelin staining studies. Interestingly, the pRF sizes and visual field signs of both quadrant representations in V3 are not different. Although myelin density correlates with curvature and anticorrelates with cortical thickness when measured across the entire cortex, exactly as in humans, the myelin density results in the visual areas cannot be explained by variability in cortical thickness and curvature between these areas. The present myelin density results largely support our previous model to group the two quadrants of DLP and V3A, rather than grouping DLP- with V3v into a single area VLP, or V3d with V3A+ into DM.

scholarly journals Detecting moving objects in an optic flow field using direction- and speed-tuned operators

2014 ◽  
Vol 98 ◽  
pp. 14-25 ◽  
Author(s):  
Constance S. Royden ◽  
Michael A. Holloway
Keyword(s):  
Flow Field ◽  
Optic Flow ◽  
Moving Objects

On the Relation between Visual Spatial Attention and Visual Field Asymmetries

1992 ◽  
Vol 44 (3) ◽  
pp. 529-555 ◽  
Author(s):  
T. A Mondor ◽  
M.P. Bryden
Keyword(s):  
Visual Field ◽  
Visual Attention ◽  
Visual Fields ◽  
Stimulus Onset ◽  
Right Visual Field ◽  
Structural Factors ◽  
Letter Identification ◽  
Functional Capabilities ◽  
Visual Spatial ◽  
The Right

In the typical visual laterality experiment, words and letters are more rapidly and accurately identified in the right visual field than in the left. However, while such studies usually control fixation, the deployment of visual attention is rarely restricted. The present studies investigated the influence of visual attention on the visual field asymmetries normally observed in single-letter identification and lexical decision tasks. Attention was controlled using a peripheral cue that provided advance knowledge of the location of the forthcoming stimulus. The time period between the onset of the cue and the onset of the stimulus (Stimulus Onset Asynchrony—SOA) was varied, such that the time available for attention to focus upon the location was controlled. At short SO As a right visual field advantage for identifying single letters and for making lexical decisions was apparent. However, at longer SOAs letters and words presented in the two visual fields were identified equally well. It is concluded that visual field advantages arise from an interaction of attentional and structural factors and that the attentional component in visual field asymmetries must be controlled in order to approximate more closely a true assessment of the relative functional capabilities of the right and left cerebral hemispheres.

Equal Degrees of Object Selectivity for Upper and Lower Visual Field Stimuli

2010 ◽  
Vol 104 (4) ◽  
pp. 2075-2081 ◽  
Author(s):  
Lars Strother ◽  
Adrian Aldcroft ◽  
Cheryl Lavell ◽  
Tutis Vilis
Keyword(s):  
Visual Field ◽  
Occipital Cortex ◽  
Recognition System ◽  
Blood Oxygen Level Dependent ◽  
Lower Visual Field ◽  
Blood Oxygen Level ◽  
Visual Areas ◽  
Bold Responses ◽  
Cortical Regions ◽  
Lateral Occipital Cortex

Functional MRI (fMRI) studies of the human object recognition system commonly identify object-selective cortical regions by comparing blood oxygen level–dependent (BOLD) responses to objects versus those to scrambled objects. Object selectivity distinguishes human lateral occipital cortex (LO) from earlier visual areas. Recent studies suggest that, in addition to being object selective, LO is retinotopically organized; LO represents both object and location information. Although LO responses to objects have been shown to depend on location, it is not known whether responses to scrambled objects vary similarly. This is important because it would suggest that the degree of object selectivity in LO does not vary with retinal stimulus position. We used a conventional functional localizer to identify human visual area LO by comparing BOLD responses to objects versus scrambled objects presented to either the upper (UVF) or lower (LVF) visual field. In agreement with recent findings, we found evidence of position-dependent responses to objects. However, we observed the same degree of position dependence for scrambled objects and thus object selectivity did not differ for UVF and LVF stimuli. We conclude that, in terms of BOLD response, LO discriminates objects from non-objects equally well in either visual field location, despite stronger responses to objects in the LVF.

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