Stronger occipital cortical activation to lower than upper visual field stimuli - Neuromagnetic recordings
Stronger occipital cortical activation to lower than upper visual field stimuli - Neuromagnetic recordings
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DOI：
10.1007/s002210050625
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发表时间：
1999-02-01
影响因子：
2
通讯作者：
Hari, R
中科院分区：
文献类型：
--
作者：
Portin, K;Vanni, S;Hari, R
我们记录了全头皮脑磁图（MEG）对黑白棋盘的反应，以研究人类皮层的反应是否与在0-6度的小偏心率下刺激上下视野在数量上相似。所有刺激均在50-100 ms（平均75 ms）时引起强烈的枕部反应。在对侧枕骨皮层，靠近钙碱裂缝处，用一个等效电流偶极子模拟了这种激活，与V1/V2皮层的激活一致。偶极子对低磁场刺激的平均强度是对高磁场刺激的两倍。在源电流方向和强度上，半场刺激对上下场的响应与低场刺激的响应相似。这些结果与心理物理数据一致，表明在复杂的视觉加工中较低的视野优势。假定的Vc复合体的顶枕反应与上下野刺激相似。
We recorded whole-scalp magnetoencephalographic (MEG) responses to black-and-white checkerboards to study whether the human cortical responses are quantitatively similar to stimulation of the lower and upper visual field at small, 0-6 degrees, eccentricities. All stimuli evoked strong occipital responses peaking at 50-100 ms (mean 75 ms). The activation was modeled with a single equivalent current dipole in the contralateral occipital cortex, close to the calcarine fissure, agreeing with an activation of the V1/V2 cortex. The dipole was, on average, twice as strong to lower than to upper field stimuli. Responses to hemifield stimuli that extended to both lower and upper fields resembled the responses to lower field stimuli in source current direction and strength. These results agree with psychophysical data, which indicate lower visual field advantage in complex visual processing. Parieto-occipital responses in the putative Vc complex were similar to lower and upper field stimuli.