An fMRI study of the cerebral macro network involved in 'cue invariant' form perception and how it is influenced by stimulus complexity
An fMRI study of the cerebral macro network involved in 'cue invariant' form perception and how it is influenced by stimulus complexity
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DOI：
10.1016/j.neuroimage.2004.05.028
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发表时间：
2004-11-01
期刊：
影响因子：
5.7
通讯作者：
Martin, E
中科院分区：
文献类型：
--
作者：
Marcar, VL;Loenneker, T;Martin, E
我们研究了刺激的复杂性的影响，宏观网络的视觉领域参与的“线索不变”的形式知觉。14名健康成年志愿者在两个选择强迫选择（2-AFC）形式的歧视任务进行功能MRI成像。通过使用简单和复杂的形状来改变施加到视觉系统上的功能负荷。使用亮度、色度或运动对比度提示来定义图形。这三个线索激活了腹侧通路中相同的视觉区域，包括“LO”区域。在背侧通路中，观察到运动对比度提示激活视觉区“V3 v”，但不激活区域“KO”。简单的形状比复杂的形状在BA 18中诱导更大的BOLD反应，反映了该区域对刺激中的特征（例如边缘和顶点）的选择性。对复杂形状产生更大粗体信号的大脑区域是已知对我们的复杂刺激的正交内容具有选择性的区域。通过比较被试的反应时来评估加工要求。我们发现，简单和复杂形状的反应时间没有显着差异。对亮度对比度线索和颜色对比度线索的反应时间相同，但对运动对比度线索的反应时间要长200 ms。这一发现与神经生理学研究相一致，报告了运动对比刺激的较长起始潜伏期。这进一步支持了运动对比度提示在进入腹侧通路之前需要由背侧通路的视觉区域进行辅助处理的观点。(C)2004爱思唯尔公司All rights reserved.
We investigated the influence of stimulus complexity on the macro network of visual areas involved in 'cue invariant' form perception. Functional MRI imaging on 14 healthy, adult volunteers was performed during a two alternative forced choice (2-AFC) form discrimination task. The functional load imposed onto the visual system was varied by using simple and complex shapes. The figures were defined using a luminance, a chromatic or a motion contrast cue. The three cues activated the same visual areas in the ventral pathway, including area 'LO'. Activation of visual area 'V3v' but not area 'KO' in the dorsal pathway was observed to the motion contrast cue. The simple shapes induced a larger BOLD response in BA18 than the complex shapes, reflecting the selectivity of this region for the features in the stimuli such as edges and vertices. The brain regions yielding a larger BOLD signal to the complex shapes were areas know to be selective to the orthographic content of our complex stimuli. The processing requirement was assessed by comparing the subjects' reaction time. We found no significant difference in the reaction times to the simple and complex shapes. The reaction times to the luminance contrast cue and the chromatic contrast cue were identical but that to the motion contrast cue were 200 ms longer. This finding concurs with neurophysiological studies, reporting a longer onset latency for motion contrast stimuli. It further lends support to the idea that the motion contrast cue requires auxiliary processing by the visual areas of the dorsal pathway before entry into the ventral pathway. (C) 2004 Elsevier Inc. All rights reserved.