Object-selective cortex exhibits performance-independent repetition suppression
Object-selective cortex exhibits performance-independent repetition suppression
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DOI：
10.1152/jn.00500.2005
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发表时间：
2006-02-01
影响因子：
2.5
通讯作者：
Grill-Spector, K
中科院分区：
文献类型：
--
作者：
Sayres, R;Grill-Spector, K
当重复物体刺激时，物体选择性皮层区域表现出降低的反应[重复抑制（RS）]。RS通常与启动有关：减少反应时间和增加重复刺激的准确性。目前还不清楚RS是否反映了刺激特异性重复，反应时间的相关变化，或两者的组合。为了解决这个问题，我们进行了一个快速的事件相关的功能性磁共振成像（fMRI）的研究中，我们测量BOLD信号在对象选择皮层，以及对象识别性能，而我们操纵刺激重复。我们的设计使我们能够分别研究反应时间和重复在解释RS中的作用。我们发现，重复在解释RS中发挥了强大的作用：重复试验产生较弱的BOLD反应比nonrepeated试验，即使在比较试验匹配的响应时间。与此相反，响应时间发挥了微弱的作用，在解释RS时，重复控制：它只解释了BOLD反应的一个区域的利益（ROI）和一个实验条件。因此，重复抑制似乎主要是由重复而不是性能变化驱动的。我们进一步研究是否RS反映过程发生在同一时间的识别或识别后，通过操纵刺激呈现持续时间。在一个实验中，持续时间长于识别所需的时间（2秒），而在第二个实验中，持续时间接近识别所需的最小时间（85-101毫秒）。我们发现了重要的RS简短的介绍（虽然幅度降低），这再次坚持控制性能时。这表明在确认过程中发生了大量的RS。
Object-selective cortical regions exhibit a decreased response when an object stimulus is repeated [ repetition suppression (RS)]. RS is often associated with priming: reduced response times and increased accuracy for repeated stimuli. It is unknown whether RS reflects stimulus-specific repetition, the associated changes in response time, or the combination of the two. To address this question, we performed a rapid event-related functional MRI (fMRI) study in which we measured BOLD signal in object-selective cortex, as well as object recognition performance, while we manipulated stimulus repetition. Our design allowed us to examine separately the roles of response time and repetition in explaining RS. We found that repetition played a robust role in explaining RS: repeated trials produced weaker BOLD responses than nonrepeated trials, even when comparing trials with matched response times. In contrast, response time played a weak role in explaining RS when repetition was controlled for: it explained BOLD responses only for one region of interest (ROI) and one experimental condition. Thus repetition suppression seems to be mostly driven by repetition rather than performance changes. We further examined whether RS reflects processes occurring at the same time as recognition or after recognition by manipulating stimulus presentation duration. In one experiment, durations were longer than required for recognition (2s), whereas in a second experiment, durations were close to the minimum time required for recognition ( 85-101 ms). We found significant RS for brief presentations (albeit with a reduced magnitude), which again persisted when controlling for performance. This suggests a substantial amount of RS occurs during recognition.