An Attention-Sensitive Memory Trace in Macaque MT Following Saccadic Eye Movements.
An Attention-Sensitive Memory Trace in Macaque MT Following Saccadic Eye Movements.
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DOI：
10.1371/journal.pbio.1002390
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发表时间：
2016-02
期刊：
影响因子：
9.8
通讯作者：
Krishna BS
中科院分区：
文献类型：
--
作者：
Yao T;Treue S;Krishna BS
我们体验了一个视觉稳定的世界，尽管眼睛、头部和身体运动导致视网膜图像频繁移位。这背后的神经机制尚不清楚。一种可能的机制是跨眼跳重新映射，在这种机制中，一些神经元在注意、动眼和视觉脑区的反应似乎可以预见眼跳的后果。跨视交叉重映射的功能作用一直备受争议，其许多关键特性仍不清楚。在这里，我们记录了两只猴子在将注意力引导到两个空间位置之一时进行扫视的过程，我们发现，人类和猕猴运动处理路径中的关键区域--中间颞区(MT)的神经元显示出一种被称为记忆痕迹的跨扫视重新映射形式。自上而下的空间注意分配增强了MT神经元的记忆痕迹。据我们所知，我们的数据首次证明了自上而下的注意力对大脑中任何地方的记忆痕迹的影响。我们只发现了运动方向对记忆轨迹的小而短暂的影响的证据(并且只在两只猴子中的一只身上)，反对MT在跨眼跳的空间特征比较和适应转移的理论上关键但在经验上有争议的现象中的作用。我们的数据支持这一假设，即跨眼跳重新映射代表了视网膜地图中注意指针的转移，因此相关位置可以被跟踪并在跨眼跳中快速处理。我们的结果解决了有关视觉刺激在背侧视流中的视交叉表征的重要问题，并证明了自上而下的注意在调节这一表征中的重要作用。在眼球运动后，大脑如何跟踪特定的被关注的特征？一项对猕猴大脑的新研究表明，在跨眼跳的注意指针的重新映射中，中颞叶(MT)区域也有牵连。尽管眼睛、头部和身体的运动会导致视网膜上的图像频繁移动，但人类体验到的是一个视觉稳定的世界。人类和猴子也能够跟踪这些动作中的视觉刺激。一种可能有助于这些能力的机制是“跨眼跳重新映射”，在这种机制中，大脑不同注意、动眼和视觉区域的一些神经元的反应似乎预见到了眼跳的后果。目前的一种假说认为，大脑维持着指向相关刺激位置的“注意指针”，并通过跨视跳重新映射，迅速重新定位这些指针，以补偿干预的眼球运动。目前尚不清楚刺激特征是否也被重新映射到眼跳(以及它们的位置)。在这里，我们展示了跨视跳重映射存在于猕猴大脑对视觉运动处理至关重要的区域，即中颞区(MT)。对于有人参与的刺激计划来说，这种重新映射的反应更为强烈。我们在重新映射的响应中只发现了运动方向信息的微弱证据。这些结果支持了注意指示器假说，并首次证明了自上而下的注意对脑内跨视跳重映射的影响。
We experience a visually stable world despite frequent retinal image displacements induced by eye, head, and body movements. The neural mechanisms underlying this remain unclear. One mechanism that may contribute is transsaccadic remapping, in which the responses of some neurons in various attentional, oculomotor, and visual brain areas appear to anticipate the consequences of saccades. The functional role of transsaccadic remapping is actively debated, and many of its key properties remain unknown. Here, recording from two monkeys trained to make a saccade while directing attention to one of two spatial locations, we show that neurons in the middle temporal area (MT), a key locus in the motion-processing pathway of humans and macaques, show a form of transsaccadic remapping called a memory trace. The memory trace in MT neurons is enhanced by the allocation of top-down spatial attention. Our data provide the first demonstration, to our knowledge, of the influence of top-down attention on the memory trace anywhere in the brain. We find evidence only for a small and transient effect of motion direction on the memory trace (and in only one of two monkeys), arguing against a role for MT in the theoretically critical yet empirically contentious phenomenon of spatiotopic feature-comparison and adaptation transfer across saccades. Our data support the hypothesis that transsaccadic remapping represents the shift of attentional pointers in a retinotopic map, so that relevant locations can be tracked and rapidly processed across saccades. Our results resolve important issues concerning the perisaccadic representation of visual stimuli in the dorsal stream and demonstrate a significant role for top-down attention in modulating this representation. How does the brain keep track of specific attended features after eye movements? A new study of the macaque brain implicates the middle temporal (MT) area in the remapping of attentional pointers across saccades. Humans experience a visually stable world despite the fact that eye, head, and body movements cause frequent shifts of the image on the retina. Humans and monkeys are also able to keep track of visual stimuli across such movements. One mechanism that may contribute to these abilities is “transsaccadic remapping,” in which the responses of some neurons in various attentional, oculomotor, and visual brain areas appear to anticipate the consequences of saccades. A current hypothesis proposes that the brain maintains “attentional pointers” to the locations of relevant stimuli and that, via transsaccadic remapping, it rapidly relocates these pointers to compensate for intervening eye movements. Whether stimulus features are also remapped across saccades (along with their location) remains unclear. Here, we show the presence of transsaccadic remapping in a macaque monkey brain area critical for visual motion processing, the middle temporal area (MT). This remapped response is stronger for an attended stimulus. We find only weak evidence for motion-direction information in the remapped response. These results support the attentional pointer hypothesis and demonstrate for the first time, to our knowledge, the impact of top-down attention on transsaccadic remapping in the brain.