scholarly journals Ventral motion parallax enhances fruit fly steering to visual sideslip

2020 ◽  
Vol 16 (5) ◽  
pp. 20200046
Author(s):  
Carlos Ruiz ◽  
Jamie C. Theobald
Keyword(s):  
Visual Field ◽  
Optic Flow ◽  
Motion Parallax ◽  
Visual Fields ◽  
Fruit Fly ◽  
Depth Information ◽  
Experimental Proof ◽  
Important Region

Flies and other insects use incoherent motion (parallax) to the front and sides to measure distances and identify obstacles during translation. Although additional depth information could be drawn from below, there is no experimental proof that they use it. The finding that blowflies encode motion disparities in their ventral visual fields suggests this may be an important region for depth information. We used a virtual flight arena to measure fruit fly responses to optic flow. The stimuli appeared below ( n = 51) or above the fly ( n = 44), at different speeds, with or without parallax cues. Dorsal parallax does not affect responses, and similar motion disparities in rotation have no effect anywhere in the visual field. But responses to strong ventral sideslip (206° s −1 ) change drastically depending on the presence or absence of parallax. Ventral parallax could help resolve ambiguities in cluttered motion fields, and enhance corrective responses to nearby objects.

Distinguishing Subregions of the Human MT+ Complex Using Visual Fields and Pursuit Eye Movements

2001 ◽  
Vol 86 (4) ◽  
pp. 1991-2000 ◽  
Author(s):  
Sean P. Dukelow ◽  
Joseph F. X. DeSouza ◽  
Jody C. Culham ◽  
Albert V. van den Berg ◽  
Ravi S. Menon ◽  
...  
Keyword(s):  
Visual Field ◽  
Optic Flow ◽  
Visual Fields ◽  
Receptive Fields ◽  
Macaque Monkey ◽  
Peripheral Retina ◽  
Full Field ◽  
Medial Superior Temporal ◽  
Single Target ◽  
To Receive

In humans, functional imaging studies have demonstrated a homologue of the macaque motion complex, MT+ [suggested to contain both middle temporal (MT) and medial superior temporal (MST)], in the ascending limb of the inferior temporal sulcus. In the macaque monkey, motion-sensitive areas MT and MST are adjacent in the superior temporal sulcus. Electrophysiological research has demonstrated that while MT receptive fields primarily encode the contralateral visual field, MST dorsal (MSTd) receptive fields extend well into the ipsilateral visual field. Additionally, macaque MST has been shown to receive extraretinal smooth-pursuit eye-movement signals, whereas MT does not. We used functional magnetic resonance imaging (fMRI) and the neural properties that had been observed in monkeys to distinguish putative human areas MT from MST. Optic flow stimuli placed in the full field, or contralateral field only, produced a large cluster of functional activation in our subjects consistent with previous reports of human area MT+. Ipsilateral optic flow stimuli limited to the peripheral retina produced activation only in an anterior subsection of the MT+ complex, likely corresponding to putative MSTd. During visual pursuit of a single target, a large portion of the MT+ complex was activated. However, during nonvisual pursuit, only the anterolateral portion of the MT+ complex was activated. This subsection of the MT+ cluster could correspond to putative MSTl (lateral). In summary, we observed three distinct subregions of the human MT+ complex that were arranged in a manner similar to that seen in the monkey.

scholarly journals The subtlety of simple eyes: the tuning of visual fields to perceptual challenges in birds

2014 ◽  
Vol 369 (1636) ◽  
pp. 20130040 ◽  
Author(s):  
Graham R. Martin
Keyword(s):  
Visual Field ◽  
Phylogenetic Signal ◽  
Visual Fields ◽  
Interspecific Variation ◽  
Depth Information ◽  
Field Variation ◽  
Maximum Width ◽  
Binocular Field ◽  
Contralateral Projection ◽  
Per Se

Birds show interspecific variation both in the size of the fields of individual eyes and in the ways that these fields are brought together to produce the total visual field. Variation is found in the dimensions of all main parameters: binocular region, cyclopean field and blind areas. There is a phylogenetic signal with respect to maximum width of the binocular field in that passerine species have significantly broader field widths than non-passerines; broadest fields are found among crows (Corvidae). Among non-passerines, visual fields show considerable variation within families and even within some genera. It is argued that (i) the main drivers of differences in visual fields are associated with perceptual challenges that arise through different modes of foraging, and (ii) the primary function of binocularity in birds lies in the control of bill position rather than in the control of locomotion. The informational function of binocular vision does not lie in binocularity per se (two eyes receiving slightly different information simultaneously about the same objects from which higher-order depth information is extracted), but in the contralateral projection of the visual field of each eye. Contralateral projection ensures that each eye receives information from a symmetrically expanding optic flow-field from which direction of travel and time to contact targets can be extracted, particularly with respect to the control of bill position.

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 Investigating the Crucial Role of Optic Flow in Postural Control: Central vs. Peripheral Visual Field

2019 ◽  
Vol 9 (5) ◽  
pp. 934 ◽  
Author(s):  
Milena Raffi ◽  
Alessandro Piras
Keyword(s):  
Visual Field ◽  
Postural Control ◽  
Optic Flow ◽  
Crucial Role ◽  
Visual Fields ◽  
Upright Position ◽  
Peripheral Retina ◽  
Different Parts ◽  
Stimulation Of

Optic flow stimuli are crucial for the control of stance in the upright position. The visual control of posture has recently received a lot of interest from several researchers. One of the most intriguing aspects is the contribution of the different parts of the visual field in the control of stance. Here we reviewed the results of several studies performed with different methodologies that tried to determine the effect of optic flow on postural control, by analyzing the role of the central and peripheral visual fields. Although the results were controversial, the majority of these studies agreed to assign the most important role in postural control to the peripheral retina. However, these studies were performed using different approaches and different definitions of the central and peripheral visual fields. The choice of the exact portion of the retina to be stimulated is crucial given that the stimulation of the central and the peripheral parts of the retina leads to the activation of different geniculo-cortical pathways and results in different cortical processing of information.

Visual Field Accuracy and Eye Movement Direction: A Child's Eye View

1980 ◽  
Vol 50 (2) ◽  
pp. 631-636
Author(s):  
Evans Mandes
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Eye Movement ◽  
Visual Fields ◽  
Movement Direction

Post-exposural eye movements were studied in 32 adults and 24 7-yr.-old children. Stimuli were binary figures exposed tachistoscopically in both visual fields simultaneously. The data showed significant correlations between direction of eye movement and locus of recognition for both children and adults. No significant differences were found in frequencies of eye movements of children and adults. The data are interpreted in terms of the facilitative effects of post-exposural eye movements upon perception for both groups.

scholarly journals Functional visual fields: relationship of visual field areas to self-reported function

2017 ◽  
Vol 37 (4) ◽  
pp. 399-408 ◽  
Author(s):  
Hikmat Subhi ◽  
Keziah Latham ◽  
Joy Myint ◽  
Michael D. Crossland
Keyword(s):  
Visual Field ◽  
Visual Fields ◽  
Relationship Of

Hemispheric Specialization for Processing Chinese Characters: Some Evidence from Lexical Decision Vocal Reaction Times

1989 ◽  
Vol 69 (3_suppl) ◽  
pp. 1083-1089 ◽  
Author(s):  
Michael P. Rastatter ◽  
Gail Scukanec ◽  
Jeff Grilliot
Keyword(s):  
Visual Field ◽  
Lexical Decision ◽  
Hemispheric Specialization ◽  
Visual Fields ◽  
Reaction Times ◽  
Decision Processes ◽  
Right Visual Field ◽  
Chinese Characters ◽  
Error Type ◽  
Chinese Subjects

Lexical decision vocal reaction times (RT) were obtained for a group of Chinese subjects to unilateral tachistoscopically presented pictorial, single, and combination Chinese characters. The RT showed a significant right visual-field advantage, with significant correlations of performance between the visual fields for each type of character. Error analysis gave a significant interaction between visual fields and error type—significantly more false positive errors occurred following left visual-field inputs. These results suggest that the left hemisphere was responsible for processing each type of character, possibly reflecting superior postaccess lexical-decision processes.

Long-term visual outcome after microsurgical removal of occipital lobe cavernomas

2012 ◽  
Vol 117 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Juri Kivelev ◽  
Elina Koskela ◽  
Kirsi Setälä ◽  
Mika Niemelä ◽  
Juha Hernesniemi
Keyword(s):  
Visual Field ◽  
Visual Fields ◽  
Visual Field Loss ◽  
Occipital Lobe ◽  
Visual Outcome ◽  
Surgical Removal ◽  
Long Term Outcome ◽  
Visual Field Deficit

Object Cavernomas in the occipital lobe are relatively rare. Because of the proximity to the visual cortex and incoming subcortical tracts, microsurgical removal of occipital cavernomas may be associated with a risk of visual field defects. The goal of the study was to analyze long-term outcome after operative treatment of occipital cavernomas with special emphasis on visual outcome. Methods Of the 390 consecutive patients with cavernomas who were treated at Helsinki University Central Hospital between 1980 and 2011, 19 (5%) had occipital cavernomas. Sixteen patients (4%) were surgically treated and are included in this study. The median age was 39 years (range 3–59 years). Seven patients (56%) suffered from hemorrhage preoperatively, 5 (31%) presented with visual field deficits, 11 (69%) suffered from seizures, and 4 (25%) had multiple cavernomas. Surgery was indicated for progressive neurological deterioration. The median follow-up after surgery was 5.25 years (range 0.5–14 years). Results All patients underwent thorough neuroophthalmological assessment to determine visual outcome after surgery. Visual fields were classified as normal, mild homonymous visual field loss (not disturbing the patient, driving allowed), moderate homonymous visual field loss (disturbing the patient, driving prohibited), and severe visual field loss (total homonymous hemianopia or total homonymous quadrantanopia). At the last follow-up, 4 patients (25%) had normal visual fields, 6 (38%) had a mild visual field deficit, 1 (6%) complained of moderate visual field impairment, and 5 (31%) had severe homonymous visual field loss. Cavernomas seated deeper than 2 cm from the pial surface carried a 4.4-fold risk of postoperative visual field deficit relative to superficial ones (p = 0.034). Six (55%) of the 11 patients presenting with seizures were seizure-free postoperatively. Eleven (69%) of 16 patients had no disability during the long-term follow-up. Conclusions Surgical removal of occipital cavernomas may carry a significant risk of postoperative visual field deficit, and the risk is even higher for deeper lesions. Seizure outcome after removal of these cavernomas appeared to be worse than that after removal in other supratentorial locations. This should be taken into account during preoperative planning.

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.

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