Cattaneo Zaira, Silvanto Juha, Battelli Lorella, Pascual-Leone Alvaro
Department of Psychology, University of Milano-Bicocca, Milano, Italy.
Neurosci Lett. 2009 Oct 25;462(3):253-6. doi: 10.1016/j.neulet.2009.07.027. Epub 2009 Jul 16.
The mental number line has been shown to exert an influence on the visuo-spatial allocation of attention, with presentation of numbers from the low and high ends of the mental number line inducing covert shifts of spatial attention to the left and right side of visual space, respectively. In the present study we used transcranial magnetic stimulation (TMS) to investigate whether this attentional modulation influences excitability of the early visual cortex. By using the phosphene threshold as a measure of visual cortical excitability, we show (in 10 subjects) that number priming modulates excitability of the early visual cortex in a topographic fashion: low numbers, associated with left side of space, increase the excitability of the right early visual cortex (the stimulation of which induces phosphenes in the left hemifield) and decrease the excitability of the left early visual cortex (the stimulation of which induces phosphenes in the right hemifield). The opposite pattern of results was observed for high numbers. Our results suggest that the attentional shifts induced by the mental number line are manifested at the earliest cortical stages of visual processing.
心理数字线已被证明会对注意力的视觉空间分配产生影响，心理数字线低端和高端数字的呈现分别会引起空间注意力向视觉空间左侧和右侧的隐蔽转移。在本研究中，我们使用经颅磁刺激（TMS）来探究这种注意力调节是否会影响早期视觉皮层的兴奋性。通过将光幻视阈值作为视觉皮层兴奋性的指标，我们发现（在10名受试者中）数字启动以一种拓扑方式调节早期视觉皮层的兴奋性：与空间左侧相关的低数字会增加右侧早期视觉皮层的兴奋性（刺激该区域会在左半视野诱发光幻视），并降低左侧早期视觉皮层的兴奋性（刺激该区域会在右半视野诱发光幻视）。对于高数字，观察到相反的结果模式。我们的结果表明，心理数字线引起的注意力转移在视觉处理的最早皮层阶段就有所体现。
