Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-10-09 Cooperative journals: 《心理科学进展》
Abstract： During the development, the structure and functions of the visual system can be affected by visual experiences and environments. This is called visual plasticity which is most prominent during the critical period of development after birth. Although the structures and functions of neural circuits tend to be stable in adult visual cortex, mounting evidence has shown that adult visual cortex still retains a certain degree of plasticity, including ocular dominance plasticity. Ocular dominance in humans refers to a phenomenon that one eye is functionally superior to the other eye. A common method for measuring perceptual ocular dominance is the binocular rivalry task. The typical stimuli in this task are two spatially overlapped but incompatible images, with one presented to each eye. At any moment, observer is usually aware of only one of the images which remains visible for a while before being consciously replaced by the other one. The ratio of dominance duration for each eye in a binocular rivalry task can be used to quantitatively assess observer's ocular dominance.One of the most commonly used ways to modulate ocular dominance in adults is monocular deprivation, which shifts ocular dominance to the deprived eye through the temporary occlusion of one eye. In recent decades, researchers have extensively investigated the monocular deprivation effect and its underlying mechanism by constantly changing the way of monocular deprivation, such as depriving the energy information (e.g. contrast) or phase information (e.g. contour) of monocular images. A consistent finding is that the imbalance of visual input between two eyes, whether achieved through complete or partial deprivation of visual information to one eye, leads to a shift of ocular dominance towards the deprived eye. The shift of ocular dominance may reflect neural plasticity in the early stages of visual processing, which is closely related to the reduction of GABA inhibition in the primary visual cortex. Meanwhile, one suggested mechanism for monocular deprivation is homeostatic plasticity, an inherent mechanism that stabilizes neuronal activity and prevents the neuronal system from becoming hyperactive or hypoactive. In the context of short-term monocular deprivation, an imbalance in visual input between the two eyes may trigger a homeostatic upregulation of neural response in the deprived eye to maintain a balance of neural activity within the visual system. This can lead to a shift in ocular dominance towards the deprived eye following the monocular deprivation. More recently, it has been found that even in the absence of visual input deprivation, directing a greater amount of attention towards one eye can effectively induce an effect of ocular dominance shift. For example, a “dichoptic-backward-movie” adaptation paradigm was invented to study eye-based attention induced ocular dominance shift. The ocular dominance is biased in favor of the eye (unattended eye) that has viewed a backward movie for long during which time the opposite eye (attended eye) is presented with a regular movie. This phenomenon indicates that the neural mechanisms of short-term ocular dominance plasticity not only occur at the lower level of visual processing stage but also receive feedback regulations from higher cortical sites. Notably, the boost of the unattended eye was not observed when testing stimuli were binocularly compatible. Therefore, the attention-induced ocular dominance shift may not be explicable solely by means of the homeostatic plasticity mechanism, because the involvement of homeostasis is not specific to binocular rivalry. Given the crucial role of interocular competition in attention-induced ocular dominance shift, this effect is currently explained by the adaptation of ocular opponency neurons that represents interocular conflict by computing differences between the input signals from the two eyes. Despite significant advancements in the investigation of short-term ocular dominance plasticity, there are many promising research directions for future studies, especially those that may further our understanding of the complicated mechanisms for short-term ocular dominance plasticity. The article then ends with the outlook in this regard. Key words
Subjects: Psychology >> Cognitive Psychology submitted time 2023-05-15
Abstract： During the development, the structure and functions of the visual system can be affected by visual experiences and environments. This is called visual plasticity which is most prominent during the critical period of development after birth. Although the structures and functions of neural circuits tend to be stable in adult visual cortex, mounting evidence has shown that adult visual cortex still retains a certain degree of plasticity, including ocular dominance plasticity. In recent decades, it has been found that perceptual ocular dominance in adults can be biased by adjusting the input information or attentional allocation between the two eyes. However, the neural mechanisms underlying these different types of ocular dominance plasticity may have multiple origins. Monocular deprivation due to imbalanced visual inputs may be accounted for by the homeostatic plasticity mechanism of the visual cortex. However, the shift of ocular dominance caused by imbalanced attentional allocations between the two eyes reflects the feedbacks from higher cortical sites, which is currently explained by the adaptation of ocular opponency neurons. Future studies may provide more direct evidence for the ocular-opponency-neuron account and explore the likely interactions between attention and visual input that reshape ocular dominance.
Subjects: Psychology >> Experimental Psychology submitted time 2022-01-31
Abstract：
Eye contact plays an important role in social interaction and can capture and hold attention. Previous studies have shown that eye contact can guide attentional allocation. However, a face with direct or averted gaze is a special object containing social information. The object’s guidance for attentional allocation is called object-based attention, in which items in the cued object are processed more preferentially than items in the un-cued object. It is still unclear how eye contact interacts with objects in guiding attentional allocation. Therefore, the aim of the present study was to investigate the impact of eye contact and the cognitive mechanism of object-based attention.
We conducted three experiments using the two-rectangle paradigm and objects with different gaze directions. In Experiment 1, faces were used as stimulus and to investigate whether and how eye contact interacted with face to guide attentional allocation. At the beginning of each trial, the fixation cross and two objects originally were displayed for 1000 ms on a screen. Then, a cue appeared randomly at any of the four ends of the two objects for 100 ms. After 0, 200, or 500 ms of inter-stimulus, the target appeared until the participant pressed the “M” key or remained on screen for 1,500 ms. A black screen was then presented for 500 ms after each trial. During the experiment, the participants were asked to locate targets by pressing “M” as quickly as possible. We ruled out the influence of low-level features by using contrast reversed faces in Experiment 2. In Experiment 3, cups overlaid with eyes were used to explore whether the effect of eye contact still existed on real objects.
The results of Experiment 1 revealed that there was a significant interaction between gaze directions, cue position, and stimulus onset asynchrony (SOA). Specifically, a larger object-based effect was discovered when the cue appeared on the direct-gaze face compared to the averted-gaze face under 300-ms SOA; however, there was no significant difference between them under 100- and 600-ms SOA. Further analysis showed that the differences in object-based effect occurred because the participants reacted more quickly to the target in direct gaze than in averted gaze under the invalid same-object condition, which indicated that direct gaze could capture attention and cause a larger object-based effect. The difference in object-based effect between direct and averted gaze at 300-ms SOA disappeared in Experiment 2. The results of Experiment 3 replicated the results of Experiment 1 and further demonstrated that the influence of eye contact on object-based attention can extend to real objects.
In conclusion, the present study extends the extant literature in several dimensions. First, it provides the first evidence, to the best of our knowledge, that eye contact interacts with objects, including faces and cups, in guiding attentional allocation. The top-down processing of eye contact facilitates the processing of objects under an invalid same-object location, which leads to greater object-based attention and supports the enhancement spreading theory. Second, it also reveals that the influence of eye contact on object-based attention is regulated by SOA.
Subjects: Psychology >> Experimental Psychology submitted time 2022-01-31
Abstract： <p>Eye contact plays an important role in social interaction and can capture and hold attention. Previous studies have shown that eye contact can guide attentional allocation. However, a face with direct or averted gaze is a special object containing social information. The object’s guidance for attentional allocation is called object-based attention, in which items in the cued object are processed more preferentially than items in the un-cued object. It is still unclear how eye contact interacts with objects in guiding attentional allocation. Therefore, the aim of the present study was to investigate the impact of eye contact and the cognitive mechanism of object-based attention.</p><p>We conducted three experiments using the two-rectangle paradigm and objects with different gaze directions. In Experiment 1, faces were used as stimulus and to investigate whether and how eye contact interacted with face to guide attentional allocation. At the beginning of each trial, the fixation cross and two objects originally were displayed for 1000 ms on a screen. Then, a cue appeared randomly at any of the four ends of the two objects for 100 ms. After 0, 200, or 500 ms of inter-stimulus, the target appeared until the participant pressed the “M” key or remained on screen for 1,500 ms. A black screen was then presented for 500 ms after each trial. During the experiment, the participants were asked to locate targets by pressing “M” as quickly as possible. We ruled out the influence of low-level features by using contrast reversed faces in Experiment 2. In Experiment 3, cups overlaid with eyes were used to explore whether the effect of eye contact still existed on real objects.</p><p>The results of Experiment 1 revealed that there was a significant interaction between gaze directions, cue position, and stimulus onset asynchrony (SOA). Specifically, a larger object-based effect was discovered when the cue appeared on the direct-gaze face compared to the averted-gaze face under 300-ms SOA; however, there was no significant difference between them under 100- and 600-ms SOA. Further analysis showed that the differences in object-based effect occurred because the participants reacted more quickly to the target in direct gaze than in averted gaze under the invalid same-object condition, which indicated that direct gaze could capture attention and cause a larger object-based effect. The difference in object-based effect between direct and averted gaze at 300-ms SOA disappeared in Experiment 2. The results of Experiment 3 replicated the results of Experiment 1 and further demonstrated that the influence of eye contact on object-based attention can extend to real objects.</p><p>In conclusion, the present study extends the extant literature in several dimensions. First, it provides the first evidence, to the best of our knowledge, that eye contact interacts with objects, including faces and cups, in guiding attentional allocation. The top-down processing of eye contact facilitates the processing of objects under an invalid same-object location, which leads to greater object-based attention and supports the enhancement spreading theory. Second, it also reveals that the influence of eye contact on object-based attention is regulated by SOA.</p><p>"</p>
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