Arshad Qadeer, Nigmatullina Yuliya, Nigmatullin Ramil, Asavarut Paladd, Goga Usman, Khan Sarah, Sander Kaija, Siddiqui Shuaib, Roberts R E, Cohen Kadosh Roi, Bronstein Adolfo M, Malhotra Paresh A
Division of Brain Sciences, Imperial College London, London W6 8RF, UK.
Institut für Quantenphysik and Centre for Integrated Quantum Science and Technology (IQST), Albert Einstein Allell, Universität Ulm, Ulm D-89069, Germany.
Cereb Cortex. 2016 May;26(5):2311-2324. doi: 10.1093/cercor/bhv344. Epub 2016 Feb 14.
Numerical cognition is critical for modern life; however, the precise neural mechanisms underpinning numerical magnitude allocation in humans remain obscure. Based upon previous reports demonstrating the close behavioral and neuro-anatomical relationship between number allocation and spatial attention, we hypothesized that these systems would be subject to similar control mechanisms, namely dynamic interhemispheric competition. We employed a physiological paradigm, combining visual and vestibular stimulation, to induce interhemispheric conflict and subsequent unihemispheric inhibition, as confirmed by transcranial direct current stimulation (tDCS). This allowed us to demonstrate the first systematic bidirectional modulation of numerical magnitude toward either higher or lower numbers, independently of either eye movements or spatial attention mediated biases. We incorporated both our findings and those from the most widely accepted theoretical framework for numerical cognition to present a novel unifying computational model that describes how numerical magnitude allocation is subject to dynamic interhemispheric competition. That is, numerical allocation is continually updated in a contextual manner based upon relative magnitude, with the right hemisphere responsible for smaller magnitudes and the left hemisphere for larger magnitudes.
数字认知对现代生活至关重要；然而，支撑人类数字大小分配的精确神经机制仍不清楚。基于先前的报告表明数字分配与空间注意力之间存在密切的行为和神经解剖学关系，我们假设这些系统将受到类似的控制机制，即动态半球间竞争。我们采用了一种生理范式，结合视觉和前庭刺激，以诱导半球间冲突和随后的单侧半球抑制，经颅直流电刺激（tDCS）证实了这一点。这使我们能够首次证明数字大小向更高或更低数字的系统性双向调制，而与眼球运动或空间注意力介导的偏差无关。我们将我们的发现与数字认知最广泛接受的理论框架中的发现相结合，提出了一个新颖的统一计算模型，该模型描述了数字大小分配如何受到动态半球间竞争的影响。也就是说，数字分配基于相对大小以情境方式不断更新，右半球负责较小的大小，左半球负责较大的大小。
