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

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.

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 Perceptual inhomogeneities in the upper visual field

2010 ◽  
Vol 5 (8) ◽  
pp. 176-176 ◽  
Author(s):  
E. L. Cameron
Keyword(s):  
Visual Field ◽  
Upper Visual Field

The pupillary light reflex in normal and innate microstrabismic cats, II: Retinal and cortical input to the nucleus praetectalis olivaris

1989 ◽  
Vol 3 (2) ◽  
pp. 139-153 ◽  
Author(s):  
C. Distler ◽  
K.-P. Hoffmann
Keyword(s):  
Electrical Stimulation ◽  
Visual Field ◽  
Ganglion Cells ◽  
Occipital Cortex ◽  
Pupillary Light Reflex ◽  
Binocular Summation ◽  
Cortical Input ◽  
Light Reflex ◽  
Pupillary Light ◽  
Upper Visual Field

AbstractThe anatomical substrate of the pupillary light reflex was investigated in normal and innate microstrabismic cats using anatomical methods as well as electrical stimulation. The bilateral retinal input to the nucleus praetectalis olivaris (NPO), the pretectal relay station in the subcortical pupilloconstrictor pathway, was identified to come from the ventral retina where the upper visual field is represented. Orthodromic electrical stimulation revealed that retinal information is transmitted to on-tonic neurons in the NPO mainly via slowly conducting axons probably originating from W- and X-type retinal ganglion cells.For the first time, a direct cortical input to on-tonic neurons in the NPO could be demonstrated. This cortical input originates from caudolateral parts of the occipital cortex. Putative input structures are those subdivisions of areas 19 and 20a where the upper part of the visual field is represented.A direct, predominantly contralateral projection with a weak ipsilateral component from NPO to the nucleus of Edinger-Westphal, and an interhemispheric connection between the NPOs could be demonstrated. With respect to the anatomical connections as described in this study, no differences between normal and innate microstrabismic cats could be found.The results are discussed with respect to the binocular summation of the pupillary light reflex and its reduction in subjects with impaired binocular vision.

scholarly journals A Normal Bias Toward a Pictorially Defined Top in Line Bisection

1996 ◽  
Vol 23 (2) ◽  
pp. 110-113 ◽  
Author(s):  
Cory Toth ◽  
Andrew Kirk
Keyword(s):  
Visual Field ◽  
Normal Subjects ◽  
Line Bisection ◽  
Visual Guidance ◽  
Significant Bias ◽  
Upper Visual Field ◽  
Human Silhouette

ABSTRACT:Background: We set out to determine whether separable visual and representational components underlie normal subjects’ upward and distal biases in bisecting vertical and radial lines under visual guidance. Methods: Thirty-four normal subjects were asked to bisect lines oriented horizontally, vertically, and radially. Human silhouette figures were placed at either end of each line. These figures were presented upright or upside down in order to pictorially define a “top” to each line independent of the actual top of the visual field. Results: Although subjects erred toward the top of the visual field, they also demonstrated a significant bias toward the heads of the figures for lines in all spatial orientations. Conclusions: This result supports the existence of two biases: one toward the upper visual field, and another toward an internally represented “top” as suggested pictorially. These findings provide further support for the hypothesis that normal subjects’ upward and distal biases on bisection of vertical and radial lines under visual guidance have both representational and visual-based components.

scholarly journals A comparison of the apparent gloss of rendered objects presented in the lower and upper regions of the visual field

2021 ◽  
Author(s):  
Hua-Chun Sun ◽  
Damien John Mannion
Keyword(s):  
Visual Field ◽  
Material Properties ◽  
Visual Fields ◽  
Potential Influence ◽  
Surface Perception ◽  
Specular Reflectance ◽  
Upper Visual Field ◽  
High Degree ◽  
Field Location ◽  
Central Fixation

Gloss is an aspect of surface perception that is important for understanding the material properties of the environment. Because a surface can stimulate any region of the visual field during natural viewing, it is of interest to measure the potential influence of visual field asymmetries on perceived gloss—as such asymmetries could make the perception of gloss dependent on the visual field location. Here, our aim was to compare the apparent glossiness of renderings of nondescript objects when positioned in the lower and upper regions of the visual field. In Experiment 1, participants (n=20) evaluated the glossiness of objects presented simultaneously below and above central fixation. Estimates of the specular reflectance required for perceptual gloss equality indicated little effect of the visual field location. In Experiment 2, participants (n=19) compared the magnitude of gloss differences across two pairs of objects in either the lower or the upper visual field. Estimates of the exponent relating specular reflectance to a gloss difference scale and a noise parameter again indicated little effect of the visual field location. Overall, these estimates are consistent with the existence of a high degree of gloss constancy across presentations in the lower and upper visual fields.

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])

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