Wilke Melanie, Mueller Kai-Markus, Leopold David A
Unit on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
Proc Natl Acad Sci U S A. 2009 Jun 9;106(23):9465-70. doi: 10.1073/pnas.0900714106. Epub 2009 May 20.
To examine the role of the visual thalamus in perception, we recorded neural activity in the lateral geniculate nucleus (LGN) and pulvinar of 2 macaque monkeys during a visual illusion that induced the intermittent perceptual suppression of a bright luminance patch. Neural responses were sorted on the basis of the trial-to-trial visibility of the stimulus, as reported by the animals. We found that neurons in the dorsal and ventral pulvinar, but not the LGN, showed changes in spiking rate according to stimulus visibility. Passive viewing control sessions showed such modulation to be independent of the monkeys' active report. Perceptual suppression was also accompanied by a marked drop in low-frequency power (9-30 Hz) of the local field potential (LFP) throughout the visual thalamus, but this modulation was not observed during passive viewing. Our findings demonstrate that visual responses of pulvinar neurons reflect the perceptual awareness of a stimulus, while those of LGN neurons do not.
为了研究视觉丘脑在感知中的作用，我们在两只猕猴的外侧膝状体（LGN）和丘脑枕记录了神经活动，实验过程中利用视觉错觉诱导对一个明亮亮度斑块的间歇性感知抑制。根据动物报告的刺激在每次试验中的可见性对神经反应进行分类。我们发现，丘脑枕背侧和腹侧的神经元，而非LGN的神经元，其放电率会根据刺激的可见性发生变化。被动观看对照实验表明，这种调制与猴子的主动报告无关。感知抑制还伴随着整个视觉丘脑局部场电位（LFP）低频功率（9 - 30赫兹）的显著下降，但在被动观看期间未观察到这种调制。我们的研究结果表明，丘脑枕神经元的视觉反应反映了对刺激的感知意识，而LGN神经元的反应则不然。
