Interocular Transfer Research Articles

Honeybee Vision: Analysis of Orientation and Colour in the Lateral, Dorsal and Ventral Fields of View

The ability of honeybees (Apis mellifera) to learn and recognise peripherally presented patterns was investigated by training bees in a Y-maze which presented patterns on the side walls, the ceiling or the floor. We found that pattern orientation is learnt and recognised in the lateral and frontal visual field, but not in the dorsal or ventral fields. Colour information, in contrast, is used in the lateral and frontal as well as the ventral visual field, but not in the dorsal field. If pattern orientation is different on opposite sides of the visual field during training, both patterns are learned, but each on its own is sufficient for the bees to recognise the learnt stimulus. However, unilaterally learnt pattern information, be it orientation or colour, cannot be accessed when the test pattern is viewed on the other side. That is, interocular transfer of such information does not occur.

A reduced motion aftereffect in strabismic amblyopia

The motion aftereffect was measured using both static and dynamic test stimuli in a group of normal observers and a group of strabismic amblyopes. Amblyopes exhibited a reduced direct aftereffect for both static and dynamic stimuli and only two of the eight amblyopes exhibited any measureable interocular transfer for either test stimulus. It is hard to explain these results in terms of either the known spatial (contrast sensitivity and positional sensitivity) or motion deficits previously reported in amblyopia. These results suggest a primary motion deficit in amblyopia affecting both the static and dynamic motion aftereffects.

A view of visual adaptation from a different position

Purpose: To examine the effect of adaptation upon perceived visual location of luminance-defined and texture-defined stimuli. Methods: We describe an illusion in which 5 sec of adaptation to an antisymmetric Gaussian stimulus results in a marked perceived misalignment in a subsequently-viewed 3-Gaussian blob stimulus. The magnitude of perceived misalignment was established for various levels of adapting and test contrast. Results: The effect of varying the contrast of the adapting and test stimuli depends only upon the ratio of adapting/test contrast. Adaptation effects for luminance- and texture-defined stimuli differ in terms of inter-ocular transfer and rate of decay. Whilst adapting and testing to the same type of stimulus (luminance- or texture-defined) produces large shifts in perceived position, little or no crossover was found. The data are accounted for by a model in which the centroid of the linear combination of after-image and test stimulus is extracted. Conclusion: The perceived location of both luminance- and texture-defined stimuli can be strongly influenced by appropriate adapting stimuli. However, the adaptation processes for both types of stimuli remain independent and demonstrate different characteristics.

Patterns that impair discrimination of line orientation in human vision.

The threshold for detecting a change in orientation away from the vertical of a briefly presented foveal line target is raised when there are immediately following visual presentations. This masking effect was examined by measuring the capacity of a variety of patterns to act as masks. When patterns were made of exactly the same number of light pixels, masking was least when they formed random dots and progressively became stronger as they formed lines of decreasing curvature from full circles to straight lines. The longer the lines, the stronger the masking. Threshold elevation was highest when the masking pattern was spatially superimposed on the line and was lessened when a large surround area was included, but there was still considerable masking when the interfering patterns were confined to the surround. By placing masks and test lines in different eyes, or by giving them opposite contrast polarity, almost complete interocular and interpolarity transfer was demonstrated. Relating these results to anatomical and electrophysiological findings about neurons in the primary visual cortex leads to the conclusion that the masking effects could have their substrates in interaction between cells in VI.

Mild impairment of neuro-otological function in early treated congenital hypothyroidism

Residual binocular interaction was tested across the visual field of 9 strabismic and 2 anisometropic amblyopes in threshold and suprathreshold conditions.Binocular summation and interocular transfer of adaptation after-effects, both absent or very much reduced in the central region of the visual field of squint amblyopes, were highly significant in the periphery. The regions of preserved binocularity were well correlated with the areas for which there was no acuity loss and no interocular suppression. In anisometropic amblyopes, both binocular summation and interocular transfer of adaptation were lost at all tested eccentricities.Dynamic local stereopsis was also present in the periphery, but not in the central field of both squint and anisometropic amblyopes.

Interocular transfer in perceptual learning of a pop-out discrimination task.

The specificity of the improvement in perceptual learning is often used to localize the neuronal changes underlying this type of adult plasticity. We investigated a visual texture discrimination task previously reported to be accomplished preattentively and for which learning-related changes were inferred to occur at a very early level of the visual processing stream. The stimulus was a matrix of lines from which a target popped out, due to an orientation difference between the three target lines and the background lines. The task was to report the global orientation of the target and was performed monocularly. The subjects' performance improved dramatically with training over the course of 2-3 weeks, after which we tested the specificity of the improvement for the eye trained. In all subjects tested, there was complete interocular transfer of the learning effect. The neuronal correlate of this learning are therefore most likely localized in a visual area where input from the two eyes has come together.

Spatial frequency adaptation: Threshold elevation and perceived contrast

We have measured the spread of contrast adaptation across the dimension of spatial frequency. Threshold elevation was tightly tuned to the adapting spatial frequency but became much broader as test contrast was increased. This means that, for a given test frequency, there are some frequencies which do not raise threshold but do result in a loss of perceived contrast. The contrast dependence, retinal specificity and interocular transfer of adaptation effects elicited from same-and remote-frequency adaptation were compared. While we were able to show some distinct differences between threshold and suprathreshold tests, we were unable to demonstrate any reliable differences in the retinal specificity and interocular transfer between same- and remote-frequency adaptation.

The effect of dark and equiluminant occlusion on the interocular transfer of visual aftereffects

Lehmkuhle and Fox [(1976) Vision Research, 16, 428–430] reported that interocular transfer (IOT) of a translational motion aftereffect (MAE) was greater if the non-adapting eye viewed an equiluminant field than if it viewed a dark field. They recommended equiluminant occlusion of the non-adapted eye when measuring IOT of aftereffects. We tested this proposal in three experiments. First, we assessed IOT with equiluminant and dark occlusion for three different classes of aftereffects. Although transfer was greater with equiluminant occlusion for the translational MAE, there was no significant difference in the amount of transfer for the tilt aftereffect or the contrast threshold elevation effect. Second, we tested the hypothesis that spuriously large IOT could be the result of an aftereffect from tracking eye movements in the non-adapting eye. When potential tracking movements were reduced by using rotating spokes, a rotating spiral or contracting concentric circles, there was a corresponding reduction in the occlusion-dependent transfer. Third, we found that luminance shifts had no influence on the amount of transfer when all contours were eliminated from the non-adapting eye. We conclude that the type of occlusion used for measuring IOT of the translational MAE is important only when visible contours in the non-adapting eye contribute to the adapting process.

Failure of interocular transfer in two types of learning in the crab Chasmagnathus

Crabs (Chasmagnathus granulatus) were trained monocularly and then tested after 24 h, in order to study interocular transfer (IOT) in two habituation paradigms. 1) Habituation of the escape response to an iterated visual danger stimuli. Monocular crabs exhibited retention after 24 h when trained and tested with the same uncovered eye, but not with different uncovered eyes. 2) Habituation of the exploratory activity to a novel environment. This long term habituation of the exploratory activity is exhibited after 24 h in monocular animals trained and tested with the same uncovered eye but not with different uncovered eyes. An explanation of this failure of IOT will be discussed in terms of retrieval impairment due to a) a different perception of training and testing stimuli, b) lateralization of memory storage, or c) the existence of two symmetrical, independent and redundant lateral storage sites.

Motion aftereffect after monocular adaptation to filled-in motion at the blind spot

Although the blind spot encodes no visual information, one never perceives an odd blob or blank there, but sees a complete scene of the world even when viewing monocularly. This phenomenon called “filling-in” might be related to mechanisms essential to surface perception, but the neural representation has still been unclear. To determine at what stage the computation for filling-in is established in the visual system, whether prolonged observation of a filled-in motion including the blind spot of one eye could cause motion aftereffect at the corresponding visual field of the other eye was examined. The result was positive—interocular transfer of motion aftereffect was obtained at the tested eye. This finding suggests the possibility that real motion and filled-in motion share a common motion pathway in an early stage in the human visual system.

Induced twinkle aftereffect as a probe of dynamic visual processing mechanisms

After viewing a blank patch surrounded by a dynamic noise stimulus (a video “snowstorm”), viewers report the prolonged perception of twinkle in the unstimulated region of the blank patch. We compare this induced twinkle aftereffect to the filling-in phenomenon, which may be seen in a small blank region, under similar test conditions but during stimulation. We found that strong induced twinkle aftereffects were seen both centrally and peripherally for blank test regions from 0.5 deg to as large as 20 deg in diameter, whereas filling-in was seen centrally only for test patch diameters smaller than 0.75 deg, becoming stronger peripherally but still limited to test regions less than about 3 deg in diameter. Lower noise density and larger noise element size facilitated filling-in but had little effect on the induced twinkle aftereflect. Conversely, noise frame rate had little effect on filling-in but had to be faster than 10 frames/sec to produce a twinkle aftereflect. Induced twinkle showed binocular superiority but no interocular transfer. The binocular superiority was partially explained by monocular blankout of the dynamic noise by the blank field in the occluded eye. These results all imply a different mechanism for the induced twinkle aftereffect than for filling-in. We consider a model in which the induced twinkle aftereflect is produced by post-inhibitory rebound in complex cells.

Interocular transfer of receptive field expansion in cat visual cortex

Receptive fields in primary visual cortex have been shown to be capable of rapid expansion and contraction when exposed to an artificial scotoma, a masked segment of the visual field. To distinguish cortical from thalamic contributions to receptive field mutability, we tested interocular transfer of the effect in binocular cortical receptive fields, presenting the conditioning stimulus to the field in one eye and measuring size changes in the receptive field of the other eye. The expansion of the receptive fields in the non-conditioned eye was comparable to that in the conditioned eye. This result suggests that the expansion is due to mechanisms intrinsic to the cortex.

Color contrast induction

We report the results of psychophysical experiments on the intensive, spatial, temporal and chromatic properties of color contrast induction. Modulating the contrast of an annulus induces an apparent modulation of the color contrast of a central disk, at isoluminance. Results of varying the size of the annulus suggest that mechanisms which control contrast gain are spatially localized. Results of varying the orientations of disk and annulus patterns, with peak spatial frequencies at about 2 c/deg, suggest that the mechanisms are spatially isotropic. Results of varying the rate at which annulus contrast is modulated shows that mechanisms which mediate contrast induction have a low-pass temporal sensitivity that cuts off at about 8 Hz. Results of an experiment on the interocular transfer of color contrast induction suggest that the induction has a cortical locus. Finally, the results of varying the chromatic properties of disk and annulus suggest that the underlying mechanisms are partially, but not fully, chromatically selective.

VISION, BRAIN, AND BEHAVIOUR IN BIRDS

Part 1 The avian eye view: introduction, Sally A. McFadden producing the image, Graham R. Martin exploring the image, Hans-Ortwin Nalbach et al constructing the three-dimensional image, Sally A. McFadden the visual capabilities of birds, William Hodos colour vision of birds, Francisco J. Varela et al. Part 2 Functional anatomy of the avian visual system: introduction, Onur Gunturkun the avian visual system and the evolution of the neocortex, Toru Shimizu and Harvey J. Karten anatomy of the avian thalamofugal pathway, Onur Gunturkun et al the organization of the tectofugal pathway in birds - a comparative review, Jurgen Engelage and Hans-Joachim Bischof binocular processing in frontal-eyed birds, G. Casini et al. Part 3 Development of the avian visual system: introduction, Hans-Joachim Bischof developmental anatomy of the chick retinotectal projection, Jorg Mey and Solon Thanos development, plasticity, and differential organization of parallel processing of visual information in birds, G. Fontanesi et al development of the tectofugal visual system of normal and deprived zebra finches, Kathrin Herrmann and Hans-Joachim Bischof developmental mechanisms of lateralization, Lesley J. Rogers and Patrice Adret. Part 4 Visuomotor mechanisms: introduction, H. Philip Zeigler eye movements, head movements, and gaze stabilization in birds, Josh Wallman and Juan-Carlos Letelier sensorimotor mechanisms and pecking in the pigeon, H. Philip Zeigler et al control of pecking response topography by stimulus-reinforcer and response-reinforcer contingencies, Robert W. Allan visual mechanisms of prey capture in water birds, Gadi Katzir. Part 5 Vision and cognition: introduction, Jacky Emmerton lateralization and strategies of viewing in the domestic chick, R.J. Andrew and M. Dharmaretnam two eyes and one world - studies of interocular and intraocular transfer in birds, Monika Remy and Shigeru Watanabe what can we learn from experiments on pigeon concept discrimination?, Shigeru Watanabe et al beyond sensation - visual cognition in pigeons, Jacky Emmerton and Juan D. Delius vision, cognition, and the avian hippocampus, Verner P. Bingman.

Complete interocular transfer of motion aftereffect with flickering test

It has been suggested that motion aftereffect with static test patterns (static MAE) reflects activities at a lower level system that dominantly processes first-order motion, while MAE with a directionally ambiguous test (flicker MAE) reveals a higher level system where second-order motion signals as well as first-order signals are available. To test this hypothesis, we examined interocular transfer of static and flicker MAE. Flicker MAE should transfer more efficiently than static MAE if it occurs at a higher level system. In the first experiment, the adaptation stimulus was a drifting luminance grating (first-order motion), or a drifting grating defined by flicker or texture difference (second-order motion). The test stimulus was a luminance grating, either static or counterphasing. The results indicated that static MAE, which was induced only by first-order motion, transferred partially, as has been reported in previous studies, but the transfer of flicker MAE was nearly perfect with either first- or second-order adaptation stimuli. The second experiment with varied adaptation contrast indicated that this complete transfer was not due to a ceiling effect. These results supported the hypothesis that the underlying mechanism for flicker MAE is located at a level higher than the mechanism for static MAE.

The influence of contrast adaptation on color appearance

Most models of color vision assume that signals from the three classes of cone receptor are recoded into only three independent post-receptoral channels: one that encodes luminance and two that encode color. Stimuli that are equated for their effects on two of the channels should be discriminable only to the remaining channel, and are thus assumed to isolate the responses of single channels. We used an asymmetric matching task to examine whether such models can account for changes in color appearance following adaptation to contrast--to temporal variations in luminance and chromaticity around a fixed mean luminance and chromaticity. The experiments extend to suprathreshold color appearance the threshold adaptation paradigm of Krauskopf, Williams and Heeley [(1982) Vision Research, 32, 1123-1131]. Adaptation changes the perceived color of chromatic test stimuli both by reducing their saturation (contrast) and by changing their hue (direction within the equiluminant plane). The saturation losses are largest for test stimuli that lie along the chromatic axis defining the adapting modulation, while the hue changes are rotations away from the adapting direction and toward an orthogonal direction within the S and L-M plane. Similar selective changes in both perceived color and perceived lightness occur following adaptation to stimuli that covary in luminance and chromaticity. The selectivity of the aftereffects for multiple directions within color-luminance space is inconsistent with sensitivity changes in only three independent channels. These aftereffects suggest instead that color appearance depends on channels that can be selectively tuned to any color-luminance direction, and that there are no directions that invariably isolate responses in only a single channel. We use the perceived color changes to examine the spectral sensitivities of the chromatic channels and to estimate the distribution of channels. We also examine how adaptation alters the contrast-response function, how it affects reaction times for luminance and chromatic contrast, the extent to which the aftereffects exhibit interocular transfer, and the way in which the perceived color changes differ from those induced by conventional light adaptation.

The contribution of one-dimensional motion mechanisms to the perceived direction of drifting plaids and their aftereffects

When motion aftereffects (MAEs) are measured by adapting to a drifting plaid (simultaneous adaptation) or by adapting to the plaid's component gratings in alternation (alternating adaptation), it has been shown that the velocity and duration of the MAE are smaller in the latter case [Wenderoth, P., Bray, R. & Johnstone, S. (1988) Perception, 17, 81–91; Burke, D. & Wenderoth, P. (1993) Vision Research, 33, 351–359]. However, Burke and Wenderoth additionally reported that the directions of MAEs induced by simultaneous and alternating adaptation were identical, an apparent inconsistency if the differences in duration and velocity were due to the presence of “blobs” at the component grating intersects in the simultaneous case. Presumably, the direction of the “blobs” should also affect perceived plaid direction during adaptation and, hence, the MAE direction. In five experiments, we have measured both perceived adapting plaid and MAE direction, tested with both alternating and simultaneous adaptation, measured interocular transfer of plaid-induced MAEs and obtained MAE and plaid direction judgments under monocular and binocular viewing conditions. All of the data indicate that there is a blob tracking mechanism which is preferentially stimulated by plaids whose component gratings have high spatial frequency, low temporal frequency and high contrast. Differences between simultaneous and alternating adaptation emerge only when more optimal blobs are used, thus accounting for Burke and Wenderoth's failure to find a difference. The data also support Burke and Wenderoth's claim that the blob tracking mechanism is monocular: alternating and simultaneous adaptation produce identical MAEs under interocular transfer conditions, even using plaids with more optimal blobs. We also report the unexpected finding that plaids with more- and less-optimal blobs appear to drift in directions 20° apart yet their aftereffects differ in direction by only 3–5°. That is, more optimal blob plaids—compared with less optimal blob plaids—change both perceived plaid direction during adaptation and subsequent perceived MAE direction but the latter change is much more modest. Possible explanations of this dissociation are considered.

Interocular transfer in the split-brain rat.

Interocular transfer in the split-brain rat.

Interocular transfer in the split-brain rat.

After the 1991 development of a method to transect the optic chiasm in the rat, the authors investigated interocular transfer in split-chiasm rats with corpus callosum section and callosum intact. Rats were monocularly trained on an orientation discrimination, reversed with the other eye, and retrained with the 1st eye on the 2nd-eye problem or reversal. In split-chiasm rats, the 2nd-eye S+ (correct stimulus) showed strong transfer (55% savings) to the 1st eye. S- (incorrect stimulus) did not; reversal and transfer groups differed significantly. Split-brain rats retrained with the 1st eye on the 2nd eye S+ required no more trials than original learning, as if they had not experienced this problem. Split-brain rats retested with the original S+ showed modest (19%) savings. The findings establish interhemispheric communication via the callosum and suggest, as in findings of cat and monkey studies, the disruption of transfer by callosal section.

On interocular transfer of motion aftereffects.

A brief history of quantitative assessments of interocular transfer (IOT) of the motion aftereffect (MAE) is presented. Recent research indicates that the MAE occurs as a consequence of adapting detectors for relative rather than retinal motion. When gratings above and below a stationary, fixated grating are moved in an otherwise dark field the central, retinally stationary grafting appears to move in the opposite direction; when tested with stationary gratings an MAE is almost entirely confined to the central grating. The IOT of such an MAE was measured in experiment 1: the display was presented to one eye with a black field in the other. The IOT was about 30% of the monocular MAE. Similar values were found in experiment 2, in which the contralateral eye received an equivalent central stationary grating during adaptation and test. The dichoptic interaction of the processes involved in the MAE was examined by presenting the central gratings to both eyes and a single flanking grating above in one eye and below in the other (experiment 3). The MAE was tested with either the same or the contralateral pairing. Oppositely directed MAEs were found for the central and flanking gratings, but they were confined mainly to the conditions in which the configurations presented during adaptation were present in the same eyes during test. In experiment 4, the surround MAEs were compared after adaptation with two moving gratings in one eye or with a similar dichoptic configuration, and they were of similar duration. In a final experiment the MAE was tested either monocularly or binocularly after alternating adaptation of the left and right eyes and was found to be of the same duration. It is concluded that the MAE is a consequence of adapting relational-motion detectors, which are either monocular or of the binocular OR class.