Institute of Psychology, University of Regensburg, Regensburg, Germany.
Hum Brain Mapp. 2012 Apr;33(4):797-811. doi: 10.1002/hbm.21254. Epub 2011 Mar 21.
Multisensory integration assists us to identify objects by providing multiple cues with respect to object category and spatial location. We used a semantic audiovisual object matching task to determine the effect of spatial congruency on response behavior and fMRI brain activation. Fifteen subjects responded in a four-alternative response paradigm, which visual quadrant contained the object best matched to the sound presented. Realistic sounds based on head-related transfer functions were presented binaurally with the simulated sound source corresponding to one of the four quadrants. Following a random sequence, the location of the sound corresponded to the quadrant containing the semantically congruent target on half the trials, whereas on other trials the sound arose from an incongruent location. We examined the effects of spatial congruency on response latencies, hit-rates and fMRI responses. Preliminary behavioral results revealed a significant effect of spatial congruency on response latency or performance for stimuli with noise added. In the fMRI experiment, spatial congruency had a significant effect on the BOLD response. A cluster in the right middle and superior temporal gyrus was more activated when the auditory sound sources were spatially congruent with the semantically matching visual stimulus. In an exploratory post-hoc analysis, in which we correlated the BOLD signal with the subjects' ability to locate the sound sources, we found a significant cluster in the left inferior frontal cortex, where the BOLD response increased with sound-source localization performance. Thus spatial congruency appears to enhance the semantic integration of audiovisual object information in these brain regions.
多感觉整合通过提供与物体类别和空间位置有关的多个线索来帮助我们识别物体。我们使用语义视听物体匹配任务来确定空间一致性对反应行为和 fMRI 大脑激活的影响。15 名被试在一个四选一的反应范式中做出反应，其中视觉象限包含与呈现声音最佳匹配的物体。基于头相关传递函数的逼真声音通过双耳呈现，模拟声源对应于四个象限之一。按照随机顺序，一半试验中声音的位置与包含语义一致目标的象限相对应，而在其他试验中声音来自不一致的位置。我们检查了空间一致性对反应时、击中率和 fMRI 反应的影响。初步行为结果表明，对于添加了噪声的刺激，空间一致性对反应时或性能有显著影响。在 fMRI 实验中，空间一致性对 BOLD 反应有显著影响。当听觉声源与语义匹配的视觉刺激在空间上一致时，右侧中颞和上颞回的一个簇被更强烈地激活。在一个探索性的事后分析中，我们将 BOLD 信号与被试定位声源的能力相关联，我们发现左侧额下回有一个显著的簇，随着声源定位性能的提高，BOLD 反应也增加。因此，空间一致性似乎增强了这些脑区中视听物体信息的语义整合。
