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被眨眼打断几次。当瞳孔被眼睑遮住约100 ~ 150毫秒时，几乎感觉不到视觉流的中断。另一方面，人们也知道眨眼会受到注意力的影响。在这项研究中，我们使用脑磁图（MEG）系统，研究受试者的视觉注意如何调节眨眼相关活动。我们首先研究了枕叶和顶枕叶皮层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了比较，其中光关闭100-200毫秒。其次，我们研究了不同程度的视觉注意对自发和人工眨眼相关脑磁图活动中这些波成分的影响。我们发现，当受试者注意力不集中时，自发眨眼消失约200毫秒后，纹状体外皮层的活动就会被诱发。光输入中断后记录的相似脑磁图成分不随受试者对数字的注意状态而变化。虽然人工眨眼时的波分量不受视觉注意水平的影响，但自发眨眼时出现在顶枕皮层的慢分量在视觉注意水平较低时显著减弱。这些结果支持了眨眼后脑外皮层的活动与视觉图像的填充-撕裂机制有关的假设，提示自发眨眼过程中的信息加工可能受到眨眼前视觉注意水平的调节。我们得出结论，自发眨眼时的视觉信息加工与人工“断片”时相似，但这些信息在高级视觉皮层的后期加工受到视觉注意状态的主动控制。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