Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, 2-1, Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Brain Res. 2011 Aug 23;1408:72-80. doi: 10.1016/j.brainres.2011.06.043. Epub 2011 Jun 24.
Activation in the left primary visual cortex (V1) representing the parafoveal field during text reading has been interpreted as attentional modulation in the process of deciding saccadic target for reading ahead. Kanji words serve the main cue to decide the goal of saccades in Japanese. We aimed to determine the exact location of this modulation in the V1 and to determine whether the area of the modulation changes according to the location where the next Kanji word appears or it is fixed on a certain region in V1. Using functional magnetic resonance imaging, we determined the area in V1 representing each eccentricity on the horizontal meridian of the visual field for each participant. Then we investigated brain activation while they were reading two sets of Japanese texts that scrolled leftward as the participants. In set 1, the distance between the heads of adjacent Kanji words was about 3°. In set 2, the distance was about 5°. From the results of these experiments, we obtained activation amplitude of the area corresponding to each eccentricity. We recorded eye movements simultaneously with the acquisition of fMRI data. The maximum peak of the activation was found in the region representing about 4.5° of eccentricity on the horizontal meridian in the left V1 for each participant. The activation pattern did not essentially differ between the two text conditions, although the location of the saccades made for reading next section of the text corresponds to the head of the next Kanji word. The activation modulation during reading Japanese texts occurs in the parafoveal V1 of the left hemisphere. The attentional modulation did not change with the distance to the next goal of saccade but was fixed on the area representing about 4.5° of eccentricity.
在阅读文本时，左初级视觉皮层（V1）中代表旁视网膜区域的激活被解释为决定阅读中眼球跳动目标的注意力调节。在日语中，汉字词是决定眼球跳动目标的主要线索。我们的目的是确定 V1 中这种调节的确切位置，并确定该调节区域是否根据下一个汉字词出现的位置而改变，或者它是否固定在 V1 的某个区域上。我们使用功能磁共振成像，确定了每个参与者在水平子午线的视野中每个眼点代表的 V1 区域。然后，我们研究了参与者阅读两个向左滚动的日语文本时的大脑激活情况。在第一组中，相邻汉字词的头部之间的距离约为 3°。在第二组中，距离约为 5°。从这些实验的结果中，我们获得了对应于每个眼点的区域的激活幅度。我们在获取 fMRI 数据的同时记录了眼球运动。对于每个参与者，在左 V1 中代表水平子午线约 4.5°的眼点区域发现了最大的激活峰值。尽管阅读下一段文本的眼球跳动的目标位置与下一个汉字词的头部相对应，但两种文本条件下的激活模式没有本质区别。在阅读日语文本时，注意力调节发生在左半球的旁视网膜 V1 中。注意力调节不会随下一个眼球跳动目标的距离而改变，而是固定在代表约 4.5°眼点的区域上。
