Evidence of a direct influence between the thalamus and hMT plus independent of V1 in the human brain as measured by fMRI
Evidence of a direct influence between the thalamus and hMT plus independent of V1 in the human brain as measured by fMRI
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DOI：
10.1016/j.neuroimage.2012.01.093
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发表时间：
2012-04-02
期刊：
影响因子：
5.7
通讯作者：
Pietrini, Pietro
中科院分区：
文献类型：
--
作者：
Gaglianese, Anna;Costagli, Mauro;Pietrini, Pietro
在本研究中，我们采用条件格兰杰因果关系（CGC）和连贯性分析，以探讨视觉运动相关的信息是否直接从丘脑外侧膝状体（LGN），绕过初级视觉皮层（V1）到达人类中颞叶复合体（hMT +）。10名健康志愿者在两个视流实验中进行了脑功能磁共振成像（fMRI）检查，除了经典的LGN-V1-hMT +通路外，我们的结果显示LGN中记录的血氧水平依赖（BOLD）信号对hMT +中的信号有显著的直接影响，而不是由V1活性介导的，这有力地支持了将LGN直接连接到hMT +并服务于视觉运动处理的双侧通路的存在。此外，我们还评估了视觉运动过程中功能相关区域之间的相对延迟。以LGN为参照区，hMT +的激活峰早于V1，具有统计学意义。这种直接的途径可能发挥了重要的功能作用，更快地检测运动，并可能有助于解释持久性的无意识运动检测的个体与严重破坏的初级视觉皮层（盲视）。(c)2012 Elsevier Inc. All rights reserved.
In the present study we employed Conditional Granger Causality (CGC) and Coherence analysis to investigate whether visual motion-related information reaches the human middle temporal complex (hMT +) directly from the Lateral Geniculate Nucleus (LGN) of the thalamus, by-passing the primary visual cortex (V1). Ten healthy human volunteers underwent brain scan examinations by functional magnetic resonance imaging (fMRI) during two optic flow experiments.In addition to the classical LGN-V1-hMT + pathway, our results showed a significant direct influence of the blood oxygenation level dependent (BOLD) signal recorded in LGN over that in hMT +, not mediated by V1 activity, which strongly supports the existence of a bilateral pathway that connects LGN directly to hMT + and serves visual motion processing. Furthermore, we evaluated the relative latencies among areas functionally connected in the processing of visual motion. Using LGN as a reference region, hMT + exhibited a statistically significant earlier peak of activation as compared to V1.In conclusion, our findings suggest the co-existence of an alternative route that directly links LGN to hMT +, bypassing V1. This direct pathway may play a significant functional role for the faster detection of motion and may contribute to explain persistence of unconscious motion detection in individuals with severe destruction of primary visual cortex (blindsight). (c) 2012 Elsevier Inc. All rights reserved.