Functional imaging of the human lateral geniculate nucleus and pulvinar
Functional imaging of the human lateral geniculate nucleus and pulvinar
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DOI：
10.1152/jn.00553.2003
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发表时间：
2004-01-01
影响因子：
2.5
通讯作者：
Pinsk, MA
中科院分区：
文献类型：
--
作者：
Kastner, S;O'Connor, DH;Pinsk, MA
在人类大脑中，很少有人知道的功能解剖和反应特性的皮质下核包含视觉地图，如外侧膝状体核（LGN）和枕。使用功能磁共振成像（fMRI）在3特斯拉（T），集体反应的神经群体在LGN的刺激对比度和闪烁反转率的函数进行测量，并与视觉皮层中获得的。闪烁的棋盘刺激交替出现在右和左半野可靠地激活LGN。发现LGN激活的峰值平均在LGN解剖位置的+/-2 mm内，如在高分辨率结构图像上所识别的。在所有的视觉领域，除了中颞叶（MT），功能磁共振成像反应单调增加刺激对比度。在LGN中，对比度函数的动态响应范围较大，对比度增益低于皮层。对比敏感度在LGN和V1最低，在纹外皮质逐渐增加。在MT区，响应在4%对比度下饱和。闪烁率的变化的响应调制是相似的LGN和V1，主要发生在0.5和7.5 Hz之间的频率范围内;相反，在纹外区V4，V3 A，和MT，响应调制主要在7.5和20 Hz之间的频率范围内。在人类枕，没有激活获得与实验设计用于探测响应特性的LGN。然而，在mediodorsal的权利和左枕区域被发现一贯激活双边提出的闪烁棋盘刺激，当受试者出席的刺激。综上所述，我们的研究结果表明，在3 T的功能磁共振成像可以有效地用于研究丘脑皮层回路在人脑中。
In the human brain, little is known about the functional anatomy and response properties of subcortical nuclei containing visual maps such as the lateral geniculate nucleus (LGN) and the pulvinar. Using functional magnetic resonance imaging (fMRI) at 3 tesla (T), collective responses of neural populations in the LGN were measured as a function of stimulus contrast and flicker reversal rate and compared with those obtained in visual cortex. Flickering checkerboard stimuli presented in alternation to the right and left hemifields reliably activated the LGN. The peak of the LGN activation was found to be on average within +/-2 mm of the anatomical location of the LGN, as identified on high-resolution structural images. In all visual areas except the middle temporal (MT), fMRI responses increased monotonically with stimulus contrast. In the LGN, the dynamic response range of the contrast function was larger and contrast gain was lower than in the cortex. Contrast sensitivity was lowest in the LGN and V1 and increased gradually in extrastriate cortex. In area MT, responses were saturated at 4% contrast. Response modulation by changes in flicker rate was similar in the LGN and V1 and occurred mainly in the frequency range between 0.5 and 7.5 Hz; in contrast, in extrastriate areas V4, V3A, and MT, responses were modulated mainly in the frequency range between 7.5 and 20 Hz. In the human pulvinar, no activations were obtained with the experimental designs used to probe response properties of the LGN. However, regions in the mediodorsal right and left pulvinar were found to be consistently activated by bilaterally presented flickering checkerboard stimuli, when subjects attended to the stimuli. Taken together, our results demonstrate that fMRI at 3 T can be used effectively to study thalamocortical circuits in the human brain.