Nidiffer Aaron R, Stevenson Ryan A, Krueger Fister Juliane, Barnett Zachary P, Wallace Mark T
Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, United States.
Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, United States; Vanderbilt Brain Institute, United States; Vanderbilt University Kennedy Center, United States; Department of Psychology, University of Toronto, United States.
Neuropsychologia. 2016 Jul 29;88:83-91. doi: 10.1016/j.neuropsychologia.2016.01.031. Epub 2016 Jan 27.
Several stimulus factors are important in multisensory integration, including the spatial and temporal relationships of the paired stimuli as well as their effectiveness. Changes in these factors have been shown to dramatically change the nature and magnitude of multisensory interactions. Typically, these factors are considered in isolation, although there is a growing appreciation for the fact that they are likely to be strongly interrelated. Here, we examined interactions between two of these factors - spatial location and effectiveness - in dictating performance in the localization of an audiovisual target. A psychophysical experiment was conducted in which participants reported the perceived location of visual flashes and auditory noise bursts presented alone and in combination. Stimuli were presented at four spatial locations relative to fixation (0°, 30°, 60°, 90°) and at two intensity levels (high, low). Multisensory combinations were always spatially coincident and of the matching intensity (high-high or low-low). In responding to visual stimuli alone, localization accuracy decreased and response times (RTs) increased as stimuli were presented at more eccentric locations. In responding to auditory stimuli, performance was poorest at the 30° and 60° locations. For both visual and auditory stimuli, accuracy was greater and RTs were faster for more intense stimuli. For responses to visual-auditory stimulus combinations, performance enhancements were found at locations in which the unisensory performance was lowest, results concordant with the concept of inverse effectiveness. RTs for these multisensory presentations frequently violated race-model predictions, implying integration of these inputs, and a significant location-by-intensity interaction was observed. Performance gains under multisensory conditions were larger as stimuli were positioned at more peripheral locations, and this increase was most pronounced for the low-intensity conditions. These results provide strong support that the effects of stimulus location and effectiveness on multisensory integration are interdependent, with both contributing to the overall effectiveness of the stimuli in driving the resultant multisensory response.
在多感官整合中，有几个刺激因素很重要，包括配对刺激的空间和时间关系及其有效性。这些因素的变化已被证明会极大地改变多感官相互作用的性质和程度。通常，这些因素是单独考虑的，尽管人们越来越认识到它们可能紧密相关。在这里，我们研究了其中两个因素——空间位置和有效性——在决定视听目标定位表现方面的相互作用。我们进行了一项心理物理学实验，让参与者报告单独呈现以及组合呈现的视觉闪光和听觉噪声脉冲的感知位置。刺激相对于注视点在四个空间位置（0°、30°、60°、90°）呈现，并处于两个强度水平（高、低）。多感官组合在空间上总是重合的，且强度匹配（高-高或低-低）。单独对视觉刺激做出反应时，随着刺激在更偏心的位置呈现，定位准确性下降，反应时间（RTs）增加。对听觉刺激做出反应时，在30°和60°位置的表现最差。对于视觉和听觉刺激，强度越高，准确性越高，反应时间越快。对于视觉-听觉刺激组合的反应，在单感官表现最低的位置发现了表现增强，结果与反向有效性概念一致。这些多感官呈现的反应时间经常违反竞争模型预测，这意味着这些输入发生了整合，并且观察到了显著的位置×强度交互作用。随着刺激位于更外围的位置，多感官条件下的表现增益更大，并且这种增加在低强度条件下最为明显。这些结果有力地支持了刺激位置和有效性对多感官整合的影响是相互依存的，两者都有助于刺激在驱动最终多感官反应中的整体有效性。
