fMR-adaptation: a tool for studying the functional properties of human cortical neurons
fMR-adaptation: a tool for studying the functional properties of human cortical neurons
复制标题
DOI：
10.1016/s0001-6918(01)00019-1
复制
发表时间：
2001-04-01
影响因子：
1.8
通讯作者：
Malach, R
中科院分区：
文献类型：
--
作者：
Grill-Spector, K;Malach, R
由于功能磁共振成像的空间分辨率有限，无法直接研究人类皮层神经元的不变性。从功能磁共振成像扫描中获得的一个体素包含数十万个神经元。因此，fMRI信号可以平均出一组异质性的高度选择性神经元。在这里，我们提出了一种新的fMRI实验范式，功能磁共振适应（fMR-A），它能够标记区域内特定的神经元群并研究它们的功能特性。这种方法与测量一个区域平均活动的传统测绘方法形成了对比。fMR-A在皮质神经元功能特性研究中的应用分两个阶段进行：首先，神经元群通过重复呈现单一刺激而适应。其次，对刺激的某些性质进行了变化，并对适应后的恢复进行了评估。如果信号保持自适应状态，则表明神经元对该属性是不变的。然而，如果fMRI信号从适应状态恢复，则意味着神经元对变化的属性敏感。本文提出了一种应用fMR-A研究高阶目标区域（侧枕复合体- LOG）对目标大小、位置、光照和旋转变化的不变性的方法。结果表明，相对于光照和视点的变化，LOC对物体尺寸和位置的变化不太敏感。fMR-A可以扩展到其他神经元系统，其中适应性表现出来，也可以与事件相关范例一起使用。通过操纵实验参数和测试适应性恢复，应该有可能深入了解皮质神经元的功能特性，这些特性超出了传统功能磁共振成像所施加的空间分辨率限制。(C) 2001年Elsevier Science B.V.出版
The invariant properties of human cortical neurons cannot be studied directly by fMRI due to its limited spatial resolution. One voxel obtained from a fMRI scan contains several hundred thousands neurons. Therefore, the fMRI signal may average out a heterogeneous group of highly selective neurons. Here, we present a novel experimental paradigm for fMRI, functional magnetic resonance-adaptation (fMR-A), that enables to tag specific neuronal populations within an area and investigate their functional properties. This approach contrasts with conventional mapping methods that measure the averaged activity of a region. The application of fMR-A to study the functional properties of cortical neurons proceeds in two stages: First, the neuronal population is adapted by repeated presentation of a single stimulus. Second, some property of the stimulus is varied and the recovery from adaptation is assessed. If the signal remains adapted, it will indicate that the neurons are invariant to that attribute. However, if the fMRI signal will recover from the adapted state it would imply that the neurons are sensitive to the property that was varied. Here, an application of fMR-A for studying the invariant properties of high-order object areas (lateral occipital complex - LOG) to changes in object size, position, illumination and rotation is presented. The results show that LOC is less sensitive to changes in object size and position compared to changes of illumination and viewpoint. fMR-A can be extended to other neuronal systems in which adaptation is manifested and can be used with event-related paradigms as well. By manipulating experimental parameters and testing recovery from adaptation it should be possible to gain insight into the functional properties of cortical neurons which are beyond the spatial resolution limits imposed by conventional fMRI. (C) 2001 Published by Elsevier Science B.V.