Comparison of Human Occipital Cortical Activation to Lower and Upper Visual Field Stimuli

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 319-319
Author(s):  
K Portin ◽  
S Vanni ◽  
R Hari
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Cortical Activation ◽  
Field Stimulation ◽  
Evoked Responses ◽  
Black Dot ◽  
Lower Field ◽  
Lower Quadrant ◽  
Upper Visual Field ◽  
Source Current

We compared cortical responses to lower and upper quadrant and full hemifield stimuli (90° and 180° sectors of circular checkerboards) measured from 15 healthy subjects with a Neuromag-122™ whole-scalp neuromagnetometer. The 0.2 s stimuli were presented once every second, while the subjects fixated a black dot in the centre of the screen. The first evoked responses, peaking at 70 ms in the contralateral hemisphere, were stronger for lower than for upper field stimulation (13/15 subjects, LVF; 11/15 RVF). The sources of the evoked responses, modelled as equivalent current dipoles, clustered around the calcarine fissure, with a trend for stronger sources after lower than after upper field stimulation (on average 12% LVF; 40% RVF; ns). Attention-related visual processing may be enhanced in the lower compared with the upper visual field (Rubin et al, 1996 Science271 651 – 653). Although our data showed a strong tendency to larger responses for lower than for upper visual field stimuli, this difference was not significant for source strengths, mainly because of different source depths for upper and lower field stimuli. However, the marked similarity of source current directions for full hemifield and lower quadrant stimuli (15° - 35° upwards from the horizontal axis, viewed from back, compared with directions 15° - 25° downwards for upper field stimuli) suggest that visual input from the lower field is preferred already at early stages of the human visual system.

scholarly journals Topographic organization of the “third tier” dorsomedial visual cortex in the macaque

2019 ◽  
Author(s):  
Kostas Hadjidimitrakis ◽  
Sophia Bakola ◽  
Tristan A. Chaplin ◽  
Hsin-Hao Yu ◽  
Omar Alanazi ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Visual Processing ◽  
Large Scale ◽  
Receptive Fields ◽  
Topographic Map ◽  
Lower Quadrant ◽  
Functional Studies ◽  
The Third ◽  
Upper Visual Field

AbstractThe boundaries of the visual areas located anterior to V2 in the dorsomedial region of the macaque cortex remain contentious. This region is usually conceptualized as including two functional subdivisions: the dorsal component of area V3 (V3d), laterally, and another area, named the parietooccipital area (PO) or V6, medially. However, the nature of the putative border between V3d and PO/V6 has remained undefined. We recorded the receptive fields of multiunit clusters in adult male macaques, and reconstructed the locations of recording sites using histological sections and “unfolded” cortical maps. Immediately adjacent to dorsomedial V2 we observed a representation of the lower contralateral quadrant, which represented the vertical meridian at its rostral border. This region, corresponding to V3d of previous studies, formed a simple eccentricity gradient, from approximately <5° in the annectant gyrus, to >60° in the parietooccipital sulcus. However, there was no topographic reversal where one would expect to find the border between V3d and PO/V6. Rather, near the midline, this lower quadrant map continued directly into a representation of the peripheral upper visual field, without an intervening lower quadrant representation that could be unambiguously assigned to PO/V6. Thus, V3d and PO/V6 form a continuous topographic map, which includes parts of both quadrants. Together with previous observations that V3d and PO/V6 are both densely myelinated relative to adjacent cortex, and share similar input from V1, these results suggest that they are parts of a single area, which is distinct from the one forming the ventral component of the third tier complex.Significance statementThe primate visual cortex has a large number of areas. Knowing the extent of each visual area, and how they can be distinguished from each other, are essential for the interpretation of experiments aimed at understanding visual processing. Currently, there are conflicting models of the organization of the dorsomedial visual cortex rostral to area V2 (one of the earliest stages of cortical processing of vision). By conducting large-scale electrophysiological recordings, we found that what were originally thought to be distinct areas in this region (dorsal V3, and the parietooccipital area [PO/V6]), together form a single map the visual field. These results will help guide future functional studies, and the interpretation of the outcomes of lesions involving the dorsal visual cortex.

scholarly journals Mouse retinal specializations reflect knowledge of natural environment statistics

2020 ◽  
Author(s):  
Yongrong Qiu ◽  
Zhijian Zhao ◽  
David Klindt ◽  
Magdalena Kautzky ◽  
Klaudia P. Szatko ◽  
...  
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Natural Scenes ◽  
Lower Visual Field ◽  
Natural Scene Statistics ◽  
Predator Detection ◽  
Chromatic Contrast ◽  
Enhanced Sensitivity ◽  
Upper Visual Field ◽  
Environmental Difference

SummaryPressures for survival drive sensory circuit adaption to a species’ habitat, making it essential to statistically characterise natural scenes. Mice, a prominent visual system model, are dichromatic with enhanced sensitivity to green and UV. Their visual environment, however, is rarely considered. Here, we built a UV-green camera to record footage from mouse habitats. We found chromatic contrast to greatly diverge in the upper but not the lower visual field, an environmental difference that may underlie the species’ superior colour discrimination in the upper visual field. Moreover, training an autoencoder on upper but not lower visual field scenes was sufficient for the emergence of colour-opponent filters. Furthermore, the upper visual field was biased towards dark UV contrasts, paralleled by more light-offset-sensitive cells in the ventral retina. Finally, footage recorded at twilight suggests that UV promotes aerial predator detection. Our findings support that natural scene statistics shaped early visual processing in evolution.Lead contactFurther information and requests for resources and reagents should be directed to and will be fulfilled by the Lead Contact, Thomas Euler ([email protected])

scholarly journals The Topography of Visuospatial Attention as Revealed by a Novel Visual Field Mapping Technique

2009 ◽  
Vol 21 (7) ◽  
pp. 1447-1460 ◽  
Author(s):  
Julie A. Brefczynski-Lewis ◽  
Ritobrato Datta ◽  
James W. Lewis ◽  
Edgar A. DeYoe
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Occipital Cortex ◽  
Cortical Activation ◽  
Neural Representation ◽  
Mapping Technique ◽  
Constant Area ◽  
Parietal Cortices ◽  
Visual Field Mapping ◽  
The Brain

Previously, we and others have shown that attention can enhance visual processing in a spatially specific manner that is retinotopically mapped in the occipital cortex. However, it is difficult to appreciate the functional significance of the spatial pattern of cortical activation just by examining the brain maps. In this study, we visualize the neural representation of the “spotlight” of attention using a back-projection of attention-related brain activation onto a diagram of the visual field. In the two main experiments, we examine the topography of attentional activation in the occipital and parietal cortices. In retinotopic areas, attentional enhancement is strongest at the locations of the attended target, but also spreads to nearby locations and even weakly to restricted locations in the opposite visual field. The dispersion of attentional effects around an attended site increases with the eccentricity of the target in a manner that roughly corresponds to a constant area of spread within the cortex. When averaged across multiple observers, these patterns appear consistent with a gradient model of spatial attention. However, individual observers exhibit complex variations that are unique but reproducible. Overall, these results suggest that the topography of visual attention for each individual is composed of a common theme plus a personal variation that may reflect their own unique “attentional style.”

Stimulus-Locked and Response-Locked ERP Correlates of Spatial Inhibition of Return (IOR) in Old Age

2014 ◽  
Vol 28 (3) ◽  
pp. 105-123 ◽  
Author(s):  
Elena Amenedo ◽  
Francisco-Javier Gutiérrez-Domínguez ◽  
Sara M. Mateos-Ruger ◽  
Paula Pazo-Álvarez
Keyword(s):  
Visual Field ◽  
Old Age ◽  
Visual Processing ◽  
Inhibition Of Return ◽  
Age Groups ◽  
Event Related Potential ◽  
Lower Visual Field ◽  
Response Preparation ◽  
Age Related ◽  
Upper Visual Field

Behavioral research has shown that Inhibition of Return (IOR) is preserved in old age although at longer time intervals between cue and target, which has been interpreted as reflecting a later disengagement from the cue. A recent event-related potential (ERP) study attributed this age-related pattern to an enhanced processing of the cue. Previous ERP research in young samples indicates that target and response processing are also affected by IOR, which makes interesting to study the ERP correlates of IOR from cue presentation to response execution. In this regard, in the present study stimulus-locked (cue-locked and target-locked) and response-locked ERPs were explored in healthy young and older participants. The behavioral results indicated preserved IOR in the older participants. The cue-locked ERPs could suggest that the older participants processed the cue as a warning signal to prepare for the upcoming target stimulus. Under IOR, target-locked ERPs of both age groups showed lower N1 amplitudes suggesting a suppression/inhibition of cued targets. During the P3 rising period, in young subjects a negative shift (Nd effect) to cued targets was observed in the lower visual field (LVF), and a positive shift (Pd effect) in the upper visual field. However, in the older group the Nd effect was absent suggesting a reduction of attentional resolution in the LVF. The older group showed enhanced motor activation to prepare correct responses, although IOR effects on response-locked lateralized readiness potential LRP indicated reduced response preparation to cued targets in both age groups. In general, results suggest that the older adults inhibit or reduce the visual processing of targets appearing at cued locations, and the preparation to respond to them, but with the added cost of allocating more attentional resources onto the cue and of maintaining a more effortful processing during the sequence of stimuli within the trial.

Lateral visual field stimulation reveals extrastriate cortical activation in the contralateral hemisphere: an fMRI study

2004 ◽  
Vol 131 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Fredric Schiffer ◽  
Felix M Mottaghy ◽  
Ram Lakhan Pandey Vimal ◽  
Perry F Renshaw ◽  
Ronald Cowan ◽  
...  
Keyword(s):  
Visual Field ◽  
Cortical Activation ◽  
Field Stimulation ◽  
Contralateral Hemisphere ◽  
Fmri Study

Stronger occipital cortical activation to lower than upper visual field stimuli

1999 ◽  
Vol 124 (3) ◽  
pp. 287-294 ◽  
Author(s):  
K. Portin ◽  
Simo Vanni ◽  
Veijo Virsu ◽  
Riitta Hari
Keyword(s):  
Visual Field ◽  
Cortical Activation ◽  
Upper Visual Field

Effect of temporal sparseness and dichoptic presentation on multifocal visual evoked potentials

2005 ◽  
Vol 22 (1) ◽  
pp. 45-54 ◽  
Author(s):  
ANDREW C. JAMES ◽  
RASA RUSECKAITE ◽  
TED MADDESS
Keyword(s):  
Visual Field ◽  
Human Subjects ◽  
Signal To Noise ◽  
Recording Time ◽  
Contrast Gain ◽  
Upper Visual Field ◽  
Multifocal Vep ◽  
Normal Human ◽  
Time Decomposition ◽  
Peak Value

Multifocal VEP (mfVEP) responses were obtained from 13 normal human subjects for nine test conditions, covering three viewing conditions (dichoptic and left and right monocular), and three different temporal stimulation forms (rapid contrast reversal, rapid pattern pulse presentation, and slow pattern pulse presentation). The rapid contrast reversal stimulus had pseudorandomized reversals of checkerboards in each visual field region at a mean rate of 25 reversals/s, similar to most mfVEP studies to date. The rapid pattern pulse presentation had pseudorandomized presentations of a checkerboard for one frame, interspersed with uniform grey frames, with a mean rate of 25 presentations/s per region per eye. The slow pattern pulse stimulus had six presentations/s per region per eye. Recording time was 5.3 min/condition. For dichoptic presentation slow pattern pulse responses were 4.6 times larger in amplitude than the contrast reversal responses. Binocular suppression was greatest for the contrast reversal stimulus. Consideration of the signal-to-noise ratios indicated that to achieve a given level of reliability, slow pattern pulse stimuli would require half the recording time of contrast reversal stimuli for monocular viewing, and 0.4 times the recording time for dichoptically presented stimuli. About half the responses to the slow pattern pulse stimuli had peak value exceeding five times their estimated standard error. Responses were about 20% smaller in the upper visual field locations. Space–time decomposition showed that responses to slow pattern pulse were more consistent across visual field locations. We conclude that the pattern pulse stimuli, which we term temporally sparse, maintain the visual system in a high contrast gain state. This more than compensates for the smaller number of presentations in the run, and provides signal-to-noise advantages that may be valuable in clinical application.

scholarly journals Variations in photoreceptor throughput to mouse visual cortex and the unique effects on tuning

2020 ◽  
Author(s):  
I. Rhim ◽  
G. Coello-Reyes ◽  
I. Nauhaus
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Adaptive Filtering ◽  
Frequency Tuning ◽  
Cortical Circuits ◽  
Spatial Frequency Tuning ◽  
Upper Visual Field ◽  
Spatio Temporal ◽  
Mouse Visual Cortex ◽  
Common Laboratory

ABSTRACTVisual input to primary visual cortex (V1) depends on highly adaptive filtering in the retina. In turn, isolation of V1 computations to study cortical circuits requires control over retinal adaption and its corresponding spatio-temporal-chromatic output. Here, we first measure the balance of input to V1 from the three main photoreceptor opsins – M-opsin, S-opsin, and rhodopsin – as a function of light adaption and retinotopy. Results show that V1 is rod-mediated in common laboratory settings, yet cone-mediated in natural daylight, as evidenced by exclusive sensitivity to UV wavelengths via cone S-opsin in the upper visual field. Next, we show that cone-mediated V1 responds to 2.5-fold higher temporal frequencies than rod-mediated V1. Furthermore, cone-mediated V1 has smaller RFs, yet similar spatial frequency tuning. V1 responses in rod-deficient (Gnat1−/−) mice confirm that the effects are due to differences in photoreceptor contribution. This study provides foundation for using mouse V1 to study cortical circuits.

scholarly journals Left-right and upper-lower light sensitivity asymmetry in visual field defects caused by pituitary adenoma: a retrospective observational study

2019 ◽  
Author(s):  
Yumi Kotoda ◽  
Masakazu Kotoda ◽  
Masakazu Ogiwara ◽  
Hiroyuki Kinouchi ◽  
Hiroyuki Iijima
Keyword(s):  
Pituitary Adenoma ◽  
Visual Field ◽  
Light Sensitivity ◽  
Visual Field Defects ◽  
Lower Visual Field ◽  
Lower Quadrant ◽  
Lower Light ◽  
Left And Right ◽  
Left Right Asymmetry ◽  
Field Defects

Abstract Background While bitemporal visual field defects are characteristic in pituitary adenoma cases, it is rare to have complete bitemporal hemianopsia that is symmetrical in both eyes and has absolute scotoma throughout both temporal hemifields. Although several researches have investigated asymmetric visual field defects in patients with pituitary adenoma, no precise investigation with statistical analysis regarding the inter-eye and intra-eye symmetry of visual field defects has yet been reported. In this study, we conducted quantitative analysis to explore the asymmetric properties of visual field defects in pituitary adenoma patients. Methods Preoperative Humphrey 30-2 perimetry results were reviewed retrospectively using the charts of 28 pituitary adenoma patients who underwent surgery. Inter-eye light sensitivity comparisons of the temporal and nasal hemifields between the left and right eyes were conducted in each patient to study left-right asymmetry. Upper-lower asymmetry was investigated by comparing the frequency of severe scotoma (light sensitivity 5 dB or less) in the upper and lower visual field quadrants in the temporal and nasal hemifields. Results Left-right asymmetry was demonstrated in 61% of cases in the temporal hemifield and in 57% of cases in the nasal hemifield. Severe scotoma test points were investigated in the worse eye of each patient and were more frequent in the superotemporal quadrant of the visual field compared with the inferotemporal quadrant (P = 0.00029) and in the inferonasal quadrant compared to the superonasal quadrant (P = 0.00268). Conclusions Asymmetric visual field defects between left and right eyes are common in patients with pituitary adenoma. Severe scotoma is more frequent in the upper quadrant of the temporal hemifield and in the lower quadrant of the nasal hemifield.

scholarly journals A P300 brain-computer interface with a reduced visual field

2020 ◽  
Author(s):  
Luiza Kirasirova ◽  
Vladimir Bulanov ◽  
Alexei Ossadtchi ◽  
Alexander Kolsanov ◽  
Vasily Pyatin ◽  
...  
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Peripheral Vision ◽  
Brain Computer Interface ◽  
Basic Research ◽  
Computer Interface ◽  
Eye Tracker ◽  
Central Visual Field ◽  
P300 Speller ◽  
User Fatigue

AbstractA P300 brain-computer interface (BCI) is a paradigm, where text characters are decoded from visual evoked potentials (VEPs). In a popular implementation, called P300 speller, a subject looks at a display where characters are flashing and selects one character by attending to it. The selection is recognized by the strongest VEP. The speller performs well when cortical responses to target and non-target stimuli are sufficiently different. Although many strategies have been proposed for improving the spelling, a relatively simple one received insufficient attention in the literature: reduction of the visual field to diminish the contribution from non-target stimuli. Previously, this idea was implemented in a single-stimulus switch that issued an urgent command. To tackle this approach further, we ran a pilot experiment where ten subjects first operated a traditional P300 speller and then wore a binocular aperture that confined their sight to the central visual field. Visual field restriction resulted in a reduction of non-target responses in all subjects. Moreover, in four subjects, target-related VEPs became more distinct. We suggest that this approach could speed up BCI operations and reduce user fatigue. Additionally, instead of wearing an aperture, non-targets could be removed algorithmically or with a hybrid interface that utilizes an eye tracker. We further discuss how a P300 speller could be improved by taking advantage of the different physiological properties of the central and peripheral vision. Finally, we suggest that the proposed experimental approach could be used in basic research on the mechanisms of visual processing.

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