三维空间中视觉空间返回抑制对Simon效应的影响

通过虚拟现实技术构建虚拟三维场景,采用视觉空间返回抑制范式与Simon任务的变式相结合,操纵了目标深度、线索有效性以及空间一致性三个变量,考察三维空间深度位置上视觉空间返回抑制如何影响任务无关的反应表征(Simon效应)。结果发现,(1)三维空间深度位置上存在基于空间的返回抑制效应,且空间返回抑制效应会削减Simon效应;(2)目标出现在远处空间时,线索化条件下的Simon效应显著大于非线索化条件下的Simon效应;(3)目标出现在近处空间时,线索化条件与非线索化条件下的Simon效应之间无显著差异。研究表明,空间返回抑制并不是"深度盲",且目标的空间位置会对空间返回抑制与Simon效应的交互关系产生影响。     

三维空间深度位置上基于空间的返回抑制

采用虚拟现实技术,将Posner经典二维平面中的线索化范式应用到三维空间,通过两个实验操纵了注意沿着不同方向进行直线转移的方式,考察了注意在三维空间深度位置上进行定向/重定向而产生的晚期抑制效应(返回抑制,Inhibition of return)。结果发现：(1)无论注意沿着何种直线转移方式转移都在深度位置上发现了基于空间的返回抑制;(2)无效提示线索条件下,目标出现在三维空间近处空间时的反应显著快于目标出现在远处空间时的反应,导致了近远空间的返回抑制量存在差异。研究说明了返回抑制效应并不是“深度盲”。     

连续和同时线索化条件下的返回抑制容量

利用线索-靶子模式进行了返回抑制容量的两个实验。实验一对外周数个位置连续线索化,实验二对外周数个位置同时线索化。结果表明：(1)在连续线索化条件下,当线索化位置是相邻时,返回抑制容量可以达到4个,当线索化位置是间隔时,返回抑制容量只有1个。(2)在同时线索化条件下．当线索化位置是相邻时,返回抑制容量可以达到3个,当线索化位置是间隔时．返回抑制容量只有1个。结果支持认为存在着两种不同的返回抑制的观点,即一种是弥散性的,其容量较大;另一种是集中性的,其容量只有一个。     

线索的数量和联接性对返回抑制的影响

使用联接和离散的线索呈现方式比较了注意的易化效应和返回抑制的效果。实验一同时线索化3个外周位置,实验二同时线索化5个外周位置。结果表明：（1）在同时线索化3个位置的情境下,联接和离散这两种线索化方式均能产生返回抑制;（2）在同时线索化5个位置的情境下,联接条件仍能产生抑制效应,而离散条件没有产生。结果说明联接的方式让多个位置的线索被理解为一个线索,提示注意有“沿着物体弥散”的性质。     

多个非线索化位置易代的一项实验研究

现在采用返回抑制范式所进行的空间非信息线索作用的研究,大多以非线索化位置反应时为参照,发现线索化位置的反应先易化后抑制。后者即返回抑制。本研究采用在返回抑制范式上增设中性线索化条件的方法,发现当靶子可以出现的位置为四个时,相对于中性线索化条件,非线索化位置反应快。这种非线索化位置的易化作用是独立存在的,它能使生物体尽快地对出现在多个非线索化位置的靶子作出反应。     

多个非线索化位置易化的一项实验研究

现在采用返回抑制范式所进行的空间非信息线索作用的研究,大多以非线索化位置反应时为参照,发现线索化位置的反应先易化后抑制。后者即返回抑制。本研究采用在返回抑制范式上增设中性线索化条件的方法,发现当靶子可以出现的位置为四个时,相对于中性线索化条件,非线索化位置反应快。这种非线索化位置的易化作用是独立存在的,它能使生物体尽快地付出现在多个非线索化位置的靶子有出反应。     

返回抑制研究的新进展

Ｐｏｓｎｅｒ和Ｃｏｈｅｎ( 1984 )发现对空间某一位置进行线索化 ,在线索开始呈现到靶子开始呈现的时间间隔 (ＳＯＡ)约等于或大于 30 0毫秒时 ,被试对线索化位置上靶子的反应时长于非线索化位置 ,出现抑制效应。他们称之为返回抑制 (ｉｎｈｉｂｉｔｉｏｎｏｆｒｅｔｕｒｎ ,简称ＩＯＲ)。返回抑制的实验范式是在外周位置线索化后 ,间隔一段时间 (在此间隔时间内可插入也可不插入中央注视点线索化 ) ,然后靶子呈现在线索化位置或者非线索化位置上。早期返回抑制的研究涉及其特性和机制等多方面的问题 ,近期则倾向于将返回抑制和其它实验范…     

三维动静态场景下返回抑制的扩散

使用虚拟现实技术探讨三维动静态空间下返回抑制是否敏感于深度线索及返回抑制效应是否存在空间扩散。采用线索−靶子范式,分别设置三维静态和动态场景。结果发现：三维静态场景,不同深度及不同侧位置均发生返回抑制且产生效应大小有差异;三维动态场景,不同线索条件反应时无显著差异。结果表明,三维静态场景下,返回抑制敏感于深度线索,其效应在空间中存在扩散;客体运动破坏了返回抑制的产生及其效应的空间扩散。     

中央线索化对动态范式中基于客体的返回抑制的影响

采用3×2×3的混合实验设计,考察了三种线索-靶子呈现时间间隔条件下,中央线索化对动态范式中“基于客体的返回抑制”的影响。结果表明,在外周方框旋转同时或旋转停止后中央线索化时,出现了“基于客体的返回抑制”效应,但在外周方框旋转之前中央线索化时,“基于客体的返回抑制”效应却消失了。这说明中央线索化对动态范式中的“基于客体的返回抑制”有着重要的影响,也为动态范式中“基于客体的返回抑制”的空间位置抑制动态更新说提供了新的证据。     

意义关联的注意定向效应：基于空间位置的抑制和捕获

采用线索化范式, 通过3个实验建立线索和靶子的意义关联, 考察了意义性线索在不同空间位置的注意定向效应。结果表明, 在下视野出现抑制效应, 且位置越下抑制效应越显著; 在上视野出现捕获效应, 且位置越上捕获效应越显著; 同时注意定向效应的程度受引导线索性质的影响。这些结果说明：(1)客体间的意义关联能够引导视觉空间注意, 表现出不同空间位置的注意定向效应; (2)客体性质能够影响意义关联的注意定向, 表现为客体的生动性越高, 调节能力越强, 抽象性越高, 调节能力越弱; (3)意义关联的注意定向具有规律性变化, 表现为基于空间位置的抑制和捕获效应。     

Inhibition of return: A “depth-blind” mechanism?

When attention is oriented to a peripheral visual event, observers respond faster to stimuli presented at a cued location than at an uncued location. Following initial reaction time facilitation responses are slower to stimuli subsequently displayed at the cued location, an effect known as inhibition of return (IOR). Both facilitatory and inhibitory effects have been extensively investigated in two-dimensional space. Facilitation has also been documented in three-dimensional space, however the presence of IOR in 3D space is unclear, possibly because IOR has not been evaluated in an empty 3D space. Determining if IOR is sensitive to the depth plane of stimuli or if only their bi-dimensional location is inhibited may clarify the nature of the IOR. To address this issue, we used an attentional cueing paradigm in three-dimensional (3D) space. Results were obtained from fourteen participants showed IOR components in 3D space when binocular disparity was used to induce depth. We conclude that attentional orienting in depth operates as efficiently as in the bi-dimensional space.     

fMRI correlates of inhibition of return in perifoveal and peripheral visual field

When a target appears in the same peripheral location as a previous cue, responding is typically delayed if the cue-target interval is relatively long. This phenomenon is termed inhibition of return (IOR) and has been suggested to reflect an attentional bias in favour of novel visual space. It has been demonstrated recently that IOR is much stronger in the far periphery than in the perifoveal visual field. The present study further investigated the neural mechanisms underlying this eccentricity effect of IOR with an event-related fMRI technique. The results demonstrated a stronger activation in visual cortex for perifoveal processing and a broader activation in multiple brain areas for peripheral processing. When IOR effects were compared between these two areas, a stronger activation of the fronto-parietal network was evidenced for perifoveal versus peripheral IOR, while the prefrontal cortex was more strongly involved in the peripheral IOR versus perifoveal IOR. These results suggest that different neural mechanisms are mediating the dissociable inhibitory functions between the perifoveal and peripheral visual field.     

Inhibition of return spreads across 3-D space

Focusing attention to a location in 3–D space operates much the same as in 2–D space. Attending a location in 2–D space is followed by a selective inhibitory aftereffect known as inhibition of return (IOR). Here, we report the results of two 3–D reflexive cuing studies in which depth was defined by binocular disparity. As has been shown before, attentional cuing was specific for x–y–z locations. However, the present results show that IOR is not depth specific. After a specific location in x–y–z is cued, IOR occurs for the depth plane in front of and behind the cued location. The finding that IOR spreads across depth planes may be related to how inhibited locations are encoded in the superior colliculus. We argue that the functional role of a depth–blind IOR is to bias attention against going back to any part of a previously attended object.     

Spatial orienting in the visual field: a unified perceptual space?

Visual attention can be oriented toward a spatial location in the visual field exogenously by an abrupt onset of a peripheral cue. In a series of behavioral studies on exogenous orienting of attention with a double-cue paradigm, we demonstrated a functional subdivision of perceptual space in the visual field. Specifically, inhibition of return (IOR) is much stronger at periphery relative to perifoveal visual field up to approximately 15° eccentricity, suggesting two dissociable functional areas in the visual field. To further investigate the generality of this functional subdivision of the visual field, we measured IOR effects with another single-cue paradigm and applied a very short cue-target interval that was typically anticipated not to observe any inhibitory effect at all. Consistent with this expectation, no IOR effects at the eccentricities up to 15° were observed. However, significant IOR effects beyond 15° eccentricities were consistently demonstrated. These results not only revealed an early onset of IOR for more peripheral stimuli, but also confirmed that the perceptual space in the visual field is not homogeneous but underlies a functional subdivision with a border of ca. 15° eccentricity.     

Spatial orienting in the visual field: a unified perceptual space?

Visual attention can be oriented toward a spatial location in the visual field exogenously by an abrupt onset of a peripheral cue. In a series of behavioral studies on exogenous orienting of attention with a double-cue paradigm, we demonstrated a functional subdivision of perceptual space in the visual field. Specifically, inhibition of return (IOR) is much stronger at periphery relative to perifoveal visual field up to approximately 15° eccentricity, suggesting two dissociable functional areas in the visual field. To further investigate the generality of this functional subdivision of the visual field, we measured IOR effects with another single-cue paradigm and applied a very short cue-target interval that was typically anticipated not to observe any inhibitory effect at all. Consistent with this expectation, no IOR effects at the eccentricities up to 15° were observed. However, significant IOR effects beyond 15° eccentricities were consistently demonstrated. These results not only revealed an early onset of IOR for more peripheral stimuli, but also confirmed that the perceptual space in the visual field is not homogeneous but underlies a functional subdivision with a border of ca. 15° eccentricity.     

Two spatially separated attention systems in the visual field: evidence from inhibition of return

It has been demonstrated that the human visual field shows some functional inhomogeneities, in particular when the central and perifoveal regions are compared to the more peripheral regions. The present study examined this inhomogeneity by examining the effect of stimulus eccentricity on inhibition of return (IOR), a phenomenon that biases our attention towards novel locations against returning it back to previously attended locations. Eighteen subjects were examined in a visual detection task, in which a target appeared randomly following a nonpredictive spatial cue in the visual field. The eccentricities of the cues and targets were systematically manipulated from 5° to 30° with 5° increments. Results showed that response times to targets that appeared at cued locations were significantly slower than those at uncued locations for all stimulus eccentricities, demonstrating the IOR effects. However, response times at cued locations increased significantly when stimulus eccentricity shifted from 15° to 20°, leading to a much stronger IOR effect at more peripheral regions compared to central and perifoveal regions, indicating a functional dissociation between these two regions of the visual field. Possible neural mechanisms underlying this dissociation are discussed, and two attention systems modulating the two functional regions of the visual field are put forward to best account the present finding implicating in particular midbrain mechanism.     

The spatial distribution of inhibition of return

Inhibition of return (IOR) refers to the finding that response times (RTs) are typically slower for targets at previously attended (cued) locations than for targets at novel (uncued) locations. Although previous research has indicated that IOR may spread beyond a cued location, the present study is the first to examine the spatial distribution of IOR with high spatial resolution over a large portion of the central visual field. This was done by using a typical IOR procedure (cue, delay, target) with 4 cue locations and 441 target locations (each separated by 1° of visual angle). The results indicate that IOR spreads beyond the cued location to affect the cued hemifield. However, the cues also produced a gradient of RTs throughout the visual field, with inhibition in the cued hemifield gradually giving way to facilitation in the hemifield opposite the cue.     

Unmasking the inhibition of return phenomenon

Conventional wisdom holds that a nonpredictive peripheral cue produces a biphasic response time (RT) pattern: early facilitation at the cued location, followed by an RT delay at that location. The latter effect is called inhibition of return (IOR). In two experiments, we report that IOR occurs at a cued location far earlier than was previously thought, and that it is distinct from attentional orienting. In Experiment 1, IOR was observed early (i.e., within 50 msec) at the cued location, when the cue predicted that a detection target would occur at another location. In Experiment 2, this early IOR effect was demonstrated to occur for target detection, but not for target identification. We conclude that previous failures to observe early IOR at a cued location may have been due to attention being directed to the cued location and thus “masking” IOR.