Distribution of colour-selective activity in the monkey inferior temporal cortex revealed by functional magnetic resonance imaging
Distribution of colour-selective activity in the monkey inferior temporal cortex revealed by functional magnetic resonance imaging
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DOI：
10.1111/j.1460-9568.2009.06995.x
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发表时间：
2009-11-01
影响因子：
3.4
通讯作者：
Komatsu, Hidehiko
中科院分区：
文献类型：
--
作者：
Harada, Takuya;Goda, Naokazu;Komatsu, Hidehiko
先前的电生理、神经成像和病变研究表明，猴子的颞下皮层（IT）前部或区域TE在颜色处理中起着重要作用。然而，关于颜色信息是如何在这些皮质区域分布的，我们知之甚少。在这里，我们使用功能磁共振成像（fMRI）在两种类型的刺激下探索了警觉猕猴的颜色选择活动分布：多色（蒙德里安）图案和等光彩色光栅。这两种类型的刺激都是人类功能磁共振成像研究中常用的，但是蒙德里安刺激，包含更丰富的色调，因此可能比光栅刺激更适合激活高阶区域，在早期的猴子研究中没有被用于检查高阶区域的颜色选择性。通过蒙德里安刺激，我们观察到沿腹侧通路的区域，V1, V2/V3， V4和IT皮层，对颜色刺激的反应比亮度刺激更强烈。在IT皮层中，我们发现颜色选择活动不是均匀分布的，而是集中在离散的区域，每个区域在IT皮层的前部或后部延伸几毫米。仅在蒙德里安刺激下，后方IT的颜色选择激活被观察到，而在蒙德里安刺激和光栅刺激下，后方IT的颜色选择激活被观察到，几乎没有重叠。这些发现表明，在IT皮层中分布着具有不同刺激选择性的多个子区域，并且颜色信息在这些离散的子区域中被处理。
Previous electrophysiological, neuroimaging and lesion studies have suggested that the anterior part of the monkey inferior temporal (IT) cortex, or area TE, plays an important role in colour processing. However, little is known about how colour information is distributed in these cortical regions. Here, we explored the distribution of colour-selective activity in alert macaque monkeys using functional magnetic resonance imaging (fMRI) with two types of stimuli: a multicoloured ('Mondrian') pattern and an isoluminant colour grating. These two types of stimuli are both commonly used in human fMRI studies, but Mondrian stimuli, which contain a richer variety of hues and hence might be more suitable for activating higher-order areas than grating stimuli, have not been used to examine colour-selectivity in higher-order areas in earlier monkey studies. With the Mondrian stimuli, we observed that areas along the ventral pathway, V1, V2/V3, V4 and the IT cortex, responded more strongly to colour stimuli than to luminance stimuli. In the IT cortex, we found that colour-selective activities are not distributed uniformly, but are localized in discrete regions, each extending several millimetres in the anterior or posterior part of the IT cortex. The colour-selective activation in the anterior IT was observed only with the Mondrian stimuli, whereas the colour-selective activation in the posterior IT was observed with both the Mondrian and grating stimuli, with little overlap. These findings suggest that there are multiple subregions with differing stimulus selectivities distributed in the IT cortex, and that colour information is processed in these discrete subregions.