发表机构
Faculty of Biology, Ludwig-Maximilians-Universität München; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilians-Universität München; Bernstein Center for Computational Neuroscience Munich（慕尼黑大学动物学系; 慕尼黑大学系统神经科学研究生院; 慕尼黑贝恩斯坦计算神经科学中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过调和分析与匹配模拟，发现网格细胞放电野缺乏局部六重对称性，表明全局六边形晶格无需伴随局部六重调制，为网格形成机制提供定量约束。
AI 中文摘要
网格细胞的放电野形成六边形晶格，但每个放电野的内在几何结构仍不清楚：单个网格野是径向对称的，还是表现出继承自全局晶格的（弱）六重调制？为解决此问题，我们使用调和分析以及逐细胞匹配的模拟（在校正全局椭圆变形后保留采样统计、野尺度和晶格几何）量化了野内角度结构。我们发现，在所研究的细胞中，六重谐波功率分数与匹配的局部圆形参考野的值一致。实验野进一步表现出比施加局部六重成分的匹配模拟显著更少的六重调制，表明在该水平上对六重结构具有敏感性。这一结论得到了互补的六重回归指标、调和留一法敏感性分析以及跨径向窗口选择、平滑和模拟背景噪声水平的稳健性检查的支持。一个与观察匹配的Burak--Fiete连续吸引子网络同样未显示出选择性局部六重增强，尽管其具有全局周期性网格结构，并且当网格尺度和相对野宽度与实验条件更紧密匹配时，这一结论仍然成立。这些结果表明，全局六边形晶格组织不一定伴随单个放电野可检测的局部六重角度调制，从而对网格野微观结构和网格形成的机制模型施加了定量约束。
英文摘要
The firing fields of a grid cell form a hexagonal lattice, yet each field's intrinsic geometric structure remains unclear: Are individual grid fields radially symmetric or do they exhibit (weak) sixfold modulation inherited from the global lattice? To address this question, we quantified the within-field angular structure using harmonic analysis and per-cell matched simulations that preserved sampling statistics, field scale, and lattice geometry after correction for global elliptic deformation. We found that, across the investigated cells, the sixfold harmonic power fraction was consistent with values from matched locally circular reference fields. Experimental fields further showed substantially less sixfold modulation than matched simulations with an imposed local sixfold component, demonstrating sensitivity to sixfold structure at that level. This conclusion was supported by a complementary sixfold regression metric, harmonic leave-one-out sensitivity analyses, and robustness checks across radial-window choices, smoothing, and simulated background-noise levels. An observation-matched Burak--Fiete continuous-attractor network likewise showed no selective local sixfold enhancement despite its globally periodic grid structure, and this conclusion persisted when grid scale and relative field width were matched more closely to the experimental regime. These results suggest that the global hexagonal lattice organization need not be accompanied by detectable local sixfold angular modulation of individual firing fields, placing quantitative constraints on grid-field microstructure and mechanistic models of grid formation.
Comments58 pages, 22 figures
