A MEG study on visual information processing for spontaneous blinks and blackout during visual attention

进入大脑的视觉信息流每分钟会因眨眼而中断几次。当瞳孔被眼睑覆盖约100至150毫秒时，人们几乎不会意识到视觉流的中断。另一方面，也已经知道眨眼是由注意力改变的。本研究利用脑磁图（MEG）系统，探讨了被试的视觉注意对眨眼相关活动的调节作用。我们首先研究了枕叶和顶枕叶皮质中眨眼相关活动的波成分，然后将它们与人工眨眼激活的类似波成分进行比较，其中灯光关闭100-200毫秒。其次，我们研究了不同水平的视觉注意对自发性和人工眨眼相关脑磁活动的影响，发现当被试者处于疏忽状态时，自发性眨眼后200毫秒左右的纹外皮层活动消失 关于我们 到霜的眼睛呈现的数字。暗视输入后记录到的类似MEG成分并不随受试者对数字的注意状态而改变。虽然在人工眨眼过程中，没有一个波分量受到视觉注意水平的影响，但自发眨眼过程中出现在顶叶-枕叶皮质中的慢分量在较低的视觉注意水平下显著衰减。这些结果支持了眨眼后即刻纹状体外区的活动与视觉图像的填充-撕裂机制有关的假说，提示自发眨眼时的信息加工可能受到眨眼前视觉注意水平的调节，我们认为自发眨眼时的视觉信息加工与人工“黑障”时的视觉信息加工相似但是在高级视觉皮层中对这些信息的后期处理是由视觉注意状态主动控制的。少

Flow of visual information into the brain is disrupted several times a minute by blinking. When the pupil is covered by the eyelid for about 100 to 150 msec, one can be hardly aware of the blackout of visual flow. On the other hand, it has been also known mat blinks are modified by attention. In this study, we used MEG (magneto-encephalogram) system and investigated how the blink-related activity is modulated by subjects' visual attention. We first investigated the wave components of the blink-related activity in the occipital and parieto-occipital cortices and then compared them with the similar wave components activated by artificial blinks where light was turned off for 100-200 msec. Secondly, we investigated how different levels of visual attention affects these wave components in both spontaneous and artificial blink-related MEG activities.We found that the activity in the extrastriate cortex induced about 200msec after spontaneous blinks disappeared when subjects were inattentive … More to the numerical figures presented in frost of the eyes. The similar MEG components recorded after blackout of light input did not change depending on the state of subject's attention to numbers. While none of the wave components were affected by the level of visual attention during artificial blinks, the slow components during spontaneous blinks, which appear in the parieto-occipital cortices, were significantly attenuated at lower levels of visual attention. These results support the hypothesis that the activity in the extrastriate area immediately after blinks is related to the filling-rip mechanism of visual image and suggest that the processing of information during spontaneous blinks may be regulated according to the level of visual attention before blinking.We conclude that visual information processing during spontaneous blinks is similar to that during the artificial "blackout" but the later processing of this information in higher visual cortices is actively controlled by the state of visual attention. Less