Aron Adam R, Behrens Tim E, Smith Steve, Frank Michael J, Poldrack Russell A
Department of Psychology, University of California San Diego, La Jolla, California 92093, USA.
J Neurosci. 2007 Apr 4;27(14):3743-52. doi: 10.1523/JNEUROSCI.0519-07.2007.
The ability to stop motor responses depends critically on the right inferior frontal cortex (IFC) and also engages a midbrain region consistent with the subthalamic nucleus (STN). Here we used diffusion-weighted imaging (DWI) tractography to show that the IFC and the STN region are connected via a white matter tract, which could underlie a "hyperdirect" pathway for basal ganglia control. Using a novel method of "triangulation" analysis of tractography data, we also found that both the IFC and the STN region are connected with the presupplementary motor area (preSMA). We hypothesized that the preSMA could play a conflict detection/resolution role within a network between the preSMA, the IFC, and the STN region. A second experiment tested this idea with functional magnetic resonance imaging (fMRI) using a conditional stop-signal paradigm, enabling examination of behavioral and neural signatures of conflict-induced slowing. The preSMA, IFC, and STN region were significantly activated the greater the conflict-induced slowing. Activation corresponded strongly with spatial foci predicted by the DWI tract analysis, as well as with foci activated by complete response inhibition. The results illustrate how tractography can reveal connections that are verifiable with fMRI. The results also demonstrate a three-way functional-anatomical network in the right hemisphere that could either brake or completely stop responses.
停止运动反应的能力关键取决于右侧额下回（IFC），并且还涉及一个与丘脑底核（STN）一致的中脑区域。在这里，我们使用扩散加权成像（DWI）纤维束成像来表明IFC和STN区域通过一个白质纤维束相连，这可能是基底神经节控制的“超直接”通路的基础。使用一种对纤维束成像数据进行“三角测量”分析的新方法，我们还发现IFC和STN区域都与补充运动前区（preSMA）相连。我们假设preSMA可能在preSMA、IFC和STN区域之间的网络中发挥冲突检测/解决作用。第二个实验使用功能性磁共振成像（fMRI），采用条件性停止信号范式对这一想法进行了测试，从而能够检查冲突诱发的反应减慢的行为和神经特征。冲突诱发的反应减慢越明显，preSMA、IFC和STN区域的激活就越显著。激活与DWI纤维束分析预测的空间焦点以及完全反应抑制所激活的焦点密切相关。结果说明了纤维束成像如何能够揭示可通过fMRI验证的连接。结果还证明了右半球中一个可以制动或完全停止反应的三向功能 - 解剖网络。
