Silver Michael A, Shenhav Amitai, D'Esposito Mark
School of Optometry, University of California, Berkeley, Berkeley, CA 94720, USA.
Neuron. 2008 Dec 10;60(5):904-14. doi: 10.1016/j.neuron.2008.09.038.
Animal studies have shown that acetylcholine decreases excitatory receptive field size and spread of excitation in early visual cortex. These effects are thought to be due to facilitation of thalamocortical synaptic transmission and/or suppression of intracortical connections. We have used functional magnetic resonance imaging (fMRI) to measure the spatial spread of responses to visual stimulation in human early visual cortex. The cholinesterase inhibitor donepezil was administered to normal healthy human subjects to increase synaptic levels of acetylcholine in the brain. Cholinergic enhancement with donepezil decreased the spatial spread of excitatory fMRI responses in visual cortex, consistent with a role of acetylcholine in reducing excitatory receptive field size of cortical neurons. Donepezil also reduced response amplitude in visual cortex, but the cholinergic effects on spatial spread were not a direct result of reduced amplitude. These findings demonstrate that acetylcholine regulates spatial integration in human visual cortex.
动物研究表明，乙酰胆碱可减小早期视觉皮层中兴奋性感受野的大小并抑制兴奋的扩散。这些效应被认为是由于丘脑皮质突触传递的促进和/或皮质内连接的抑制。我们使用功能磁共振成像（fMRI）来测量人类早期视觉皮层对视觉刺激反应的空间扩散。将胆碱酯酶抑制剂多奈哌齐给予正常健康人类受试者，以提高大脑中乙酰胆碱的突触水平。多奈哌齐引起的胆碱能增强作用减小了视觉皮层中兴奋性fMRI反应的空间扩散，这与乙酰胆碱在减小皮质神经元兴奋性感受野大小方面的作用一致。多奈哌齐还降低了视觉皮层中的反应幅度，但胆碱能对空间扩散的影响并非幅度降低的直接结果。这些发现表明，乙酰胆碱调节人类视觉皮层中的空间整合。
