注意力轉(zhuǎn)移的顯著影響,，可由“注意力不集中多動癥”兒童的行為得到很好演示。人們認為,，注意力效應(yīng)出現(xiàn)在丘腦中,，但對視覺系統(tǒng)而言，事實證明,，要確定傳感處理最早階段的精確發(fā)生位置很困難。
現(xiàn)在,，McAlonan等人用獼猴所做實驗表明,，空間注意力調(diào)控發(fā)生在“外側(cè)膝狀核”中,，（使其上發(fā)生抑制性連接的）相反效應(yīng)發(fā)生在相鄰丘腦網(wǎng)狀核中。這種相互活動可能是產(chǎn)生瞬間注意力的一個機制,，從而證實了由Francis Crick在近25年前提出的一個觀點,，當時他的興趣正從DNA轉(zhuǎn)向神經(jīng)科學,。他假設(shè),，注意力的方向是由腦中的一個小核指引的，這個小核正是丘腦網(wǎng)狀核。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
