Kreiman G, Koch C, Fried I
Computation and Neural Systems Program, California Institute of Technology, Pasadena 91125, USA.
Nature. 2000 Nov 16;408(6810):357-61. doi: 10.1038/35042575.
Vivid visual images can be voluntarily generated in our minds in the absence of simultaneous visual input. While trying to count the number of flowers in Van Gogh's Sunflowers, understanding a description or recalling a path, subjects report forming an image in their "mind's eye". Whether this process is accomplished by the same neuronal mechanisms as visual perception has long been a matter of debate. Evidence from functional imaging, psychophysics, neurological studies and monkey electrophysiology suggests a common process, yet there are patients with deficits in one but not the other. Here we directly investigated the neuronal substrates of visual recall by recording from single neurons in the human medial temporal lobe while the subjects were asked to imagine previously viewed images. We found single neurons in the hippocampus, amygdala, entorhinal cortex and parahippocampal gyrus that selectively altered their firing rates depending on the stimulus the subjects were imagining. Of the neurons that fired selectively during both vision and imagery, the majority (88%) had identical selectivity. Our study reveals single neuron correlates of volitional visual imagery in humans and suggests a common substrate for the processing of incoming visual information and visual recall.
在没有同时出现视觉输入的情况下，栩栩如生的视觉图像能够在我们脑海中自主生成。当人们尝试数梵高《向日葵》中的花朵数量、理解一段描述或回忆一条路径时，受试者报告称在他们的“脑海中”形成了一幅图像。长期以来，这个过程是否由与视觉感知相同的神经元机制完成一直存在争议。来自功能成像、心理物理学、神经学研究和猴子电生理学的证据表明存在一个共同的过程，但也有患者在其中一方面存在缺陷而另一方面没有。在这里，我们通过在人类内侧颞叶记录单个神经元的活动，直接研究视觉回忆的神经元基础，同时要求受试者想象之前看过的图像。我们在海马体、杏仁核、内嗅皮质和海马旁回中发现了单个神经元，它们会根据受试者想象的刺激选择性地改变其放电频率。在视觉和意象过程中均有选择性放电的神经元中，大多数（88%）具有相同的选择性。我们的研究揭示了人类意志性视觉意象的单个神经元相关性，并表明在处理传入视觉信息和视觉回忆方面存在一个共同的基础。
