Identifying rate-limiting nodes in large-scale cortical networks for visuospatial processing: An illustration using fMRI
Identifying rate-limiting nodes in large-scale cortical networks for visuospatial processing: An illustration using fMRI
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DOI：
10.1162/08989290152001943
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发表时间：
2001-05-01
影响因子：
3.2
通讯作者：
Williams, SCR
中科院分区：
文献类型：
--
作者：
Ng, VWK;Bullmore, ET;Williams, SCR
随着功能性神经影像学技术的出现，特别是功能性磁共振成像（fMRI），我们已经获得了更深入的了解视觉空间功能的神经相关性。然而，识别与特定任务的表现最具体相关的大脑区域并不总是那么容易。一种方法是研究区域激活和行为绩效指标之间的定量关系。在本研究中，我们研究了两种不同的视觉空间加工任务，判断线方向和心理旋转的功能神经解剖学。24名正常受试者进行了功能磁共振成像扫描，采用阻断周期设计的实验任务呈现。记录每个实验中活化和基线条件的每个试验的准确度和反应时间（RT）。两个实验都激活了背侧和腹侧视觉皮层区域以及背外侧前额叶皮层。通过估计功能反应（正弦）功率和激活条件的平均RT之间的关联，确定了更多的区域特定的关联与任务性能;使用基于空间统计的排列检验进行推断。直线定向任务在右侧腹侧纹外皮层中存在显著的行为-生理关联，心理旋转任务在双侧（主要是右侧）上级顶叶小叶中存在显著的行为-生理关联。在反应能力和RT与任务的基线条件之间没有发现可比性。这些数据表明，神经认知网络中的一个区域可能与行为表现最密切相关，这可能被视为网络的计算效率最低或限速节点。
With the advent of functional neuroimaging techniques, in particular functional magnetic resonance imaging (fMRI), we have gained greater insight into the neural correlates of visuospatial function. However, it may not always be easy to identify the cerebral regions most specifically associated with performance on a given task. One approach is to examine the quantitative relationships between regional activation and behavioral performance measures. In the present study, we investigated the functional neuroanatomy of two different visuospatial processing tasks, judgement of line orientation and mental rotation. Twenty-four normal participants were scanned with fMRI using blocked periodic designs for experimental task presentation. Accuracy and reaction time (RT) to each trial of both activation and baseline conditions in each experiment was recorded. Both experiments activated dorsal and ventral visual cortical areas as well as dorsolateral prefrontal cortex. More regionally specific associations with task performance were identified by estimating the association between (sinusoidal) power of functional response and mean RT to the activation condition; a permutation test based on spatial statistics was used for inference. There was significant behavioral-physiological association in right ventral extrastriate cortex for the line orientation task and in bilateral (predominantly right) superior parietal lobule for the mental rotation task. Comparable associations were not found between power of response and RT to the baseline conditions of the tasks. These data suggest that one region in a neurocognitive network may be most strongly associated with behavioral performance and this may be regarded as the computationally least efficient or rate-limiting node of the network.