Abstract:
Evidence has shown that a variety of vertebrates, including fish, can discriminate collections of visual items on the basis of their numerousness using an evolutionarily conserved system for approximating numerical magnitude (the so-called Approximate Number System, ANS). Here we combine a habituation/dishabituation behavioural task with molecular biology assays to start investigating the neural bases of the ANS in zebrafish. Separate groups of zebrafish underwent a habituation phase with a set of 3 or 9 small red dots, associated with a food reward. The dots changed in size, position and density from trial to trial but maintained their numerousness, and the overall areas of the stimuli was kept constant. During the subsequent dishabituation test, zebrafish faced a change (i) in number (from 3 to 9 or vice versa with the same overall surface), or (ii) in shape (with the same overall surface and number), or (iii) in size (with the same shape and number). A control group of zebrafish was shown the same stimuli as during the habituation. RT-qPCR revealed that the telencephalon and thalamus were characterized by the most consistent modulation of the expression of the immediate early genes c-fos and egr-1 upon change in numerousness; in contrast, the retina and optic tectum responded mainly to changes in stimulus size.
摘要:
有证据表明,各种脊椎动物,包括鱼,可以使用进化保守的系统来近似数值大小(所谓的近似数系统,ANS).在这里,我们将习惯性/失学行为任务与分子生物学测定相结合,开始研究斑马鱼中ANS的神经基础。单独的斑马鱼组经历了一个有3或9个小红点的习惯阶段,与食物奖励有关。点的大小改变了,从审判到审判的位置和密度,但保持了它们的多样性,刺激的整体面积保持不变。在随后的失学测试中,斑马鱼面临着数量的变化(I)(从3到9,反之亦然,具有相同的整体表面),或(ii)形状(具有相同的整体表面和数量),或(iii)大小(具有相同的形状和数量)。斑马鱼的对照组显示与习惯期间相同的刺激。RT-qPCR显示,端脑和丘脑的特征是在数量变化时,立即早期基因c-fos和egr-1的表达调节最一致;相反,视网膜和视神经顶盖主要响应刺激大小的变化。