Williams Mark A, Baker Chris I, Op de Beeck Hans P, Shim Won Mok, Dang Sabin, Triantafyllou Christina, Kanwisher Nancy
McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Nat Neurosci. 2008 Dec;11(12):1439-45. doi: 10.1038/nn.2218. Epub 2008 Nov 2.
The mammalian visual system contains an extensive web of feedback connections projecting from higher cortical areas to lower areas, including primary visual cortex. Although multiple theories have been proposed, the role of these connections in perceptual processing is not understood. We found that the pattern of functional magnetic resonance imaging response in human foveal retinotopic cortex contained information about objects presented in the periphery, far away from the fovea, which has not been predicted by prior theories of feedback. This information was position invariant, correlated with perceptual discrimination accuracy and was found only in foveal, but not peripheral, retinotopic cortex. Our data cannot be explained by differential eye movements, activation from the fixation cross, or spillover activation from peripheral retinotopic cortex or from lateral occipital complex. Instead, our findings indicate that position-invariant object information from higher cortical areas is fed back to foveal retinotopic cortex, enhancing task performance.
哺乳动物视觉系统包含一个广泛的反馈连接网络,从较高皮质区域投射到较低区域,包括初级视觉皮质。尽管已经提出了多种理论,但这些连接在知觉处理中的作用仍不明确。我们发现,人类中央凹视网膜拓扑皮质中功能磁共振成像反应的模式包含了关于呈现于远离中央凹的外周物体的信息,这是先前反馈理论所未预测到的。该信息不依赖于位置,与知觉辨别准确性相关,且仅在中央凹视网膜拓扑皮质中发现,而在外周视网膜拓扑皮质中未发现。我们的数据无法用不同的眼球运动、注视十字的激活、外周视网膜拓扑皮质或枕外侧复合体的溢出激活来解释。相反,我们的研究结果表明,来自较高皮质区域的位置不变物体信息被反馈到中央凹视网膜拓扑皮质,从而提高任务表现。