[心理新知]Nature：视觉注意力调控机制在脑中的精确位置(zz)

注意力转移的显著影响，可由“注意力不集中多动症”儿童的行为得到很好演示。人们认为，注意力效应出现在丘脑中，但对视觉系统而言，事实证明，要确定传感处理最早阶段的精确发生位置很困难。

现在，McAlonan等人用猕猴所做实验表明，空间注意力调控发生在“外侧膝状核”中，（使其上发生抑制性连接的）相反效应发生在相邻丘脑网状核中。这种相互活动可能是产生瞬间注意力的一个机制，从而证实了由Francis Crick在近25年前提出的一个观点，当时他的兴趣正从DNA转向神经科学。他假设，注意力的方向是由脑中的一个小核指引的，这个小核正是丘脑网状核。

推荐原始出处：

(Nature) 456, 391-394 (20 November 2008) | doi:10.1038/nature07382

Guarding the gateway to cortex with attention in visual thalamus

Kerry McAlonan1, James Cavanaugh1 & Robert H. Wurtz1

Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA

The massive visual input from the eye to the brain requires selective processing of some visual information at the expense of other information, a process referred to as visual attention. Increases in the responses of visual neurons with attention have been extensively studied along the visual processing streams in monkey cerebral cortex, from primary visual areas to parietal and frontal cortex1, 2, 3, 4. Here we show, by recording neurons in attending macaque monkeys (Macaca mulatta), that attention modulates visual signals before they even reach cortex by increasing responses of both magnocellular and parvocellular neurons in the first relay between retina and cortex, the lateral geniculate nucleus (LGN). At the same time, attention decreases neuronal responses in the adjacent thalamic reticular nucleus (TRN). Crick5 argued for such modulation of the LGN by observing that it is inhibited by the TRN, and suggested that "if the thalamus is the gateway to the cortex, the reticular complex might be described as the guardian of the gateway", a reciprocal relationship we now show to be more than just hypothesis. The reciprocal modulation in LGN and TRN appears only during the initial visual response, but the modulation of LGN reappears later in the response, suggesting separate early and late sources of attentional modulation in LGN.

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