Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia.
Neuroimage. 2010 Sep;52(3):875-83. doi: 10.1016/j.neuroimage.2009.12.066. Epub 2009 Dec 24.
Visual experience is critical to the development of the structure of the primary visual cortex and, in turn, normal functional vision. The primary visual cortex contains maps of multiple features of the visual input, and these maps are characterised by specific types of geometric relationships. Manipulations of the visual environment during development in animals such as ferrets, cats and monkeys provide an opportunity to probe the rules governing map formation via their effect on these relationships. Here we use a computational model of map formation based on dimension-reduction principles to predict the effect on map relationships of presenting only a single orientation to one eye and the orthogonal orientation to the other eye. Since orientation preference and ocular dominance are now tightly coupled one might expect orientation and ocular dominance contours to lose their normally orthogonal relationship and instead run parallel to each other. However, surprisingly, the model predicts that orthogonal intersection can sometimes be preserved in this case. The model also predicts that orientation pinwheels can migrate from the centre to the borders of ocular dominance columns, and that the wavelengths of the ocular dominance and orientation maps can become coupled. These predictions provide a way to further test the adequacy of dimension reduction principles for explaining map structure under perturbed as well as normal rearing conditions, and thus allow us to deepen our understanding of the effect of the visual environment on visual cortical development.
视觉体验对于初级视皮层结构的发育以及正常的功能视觉至关重要。初级视皮层包含了视觉输入的多个特征的图谱，这些图谱具有特定类型的几何关系特征。在雪貂、猫和猴子等动物的发育过程中，对视觉环境进行人为操控，为通过这些关系对图谱形成的规则进行探测提供了机会。在这里，我们使用了一种基于降维原理的图谱形成计算模型，来预测仅向一只眼睛呈现单一方向，而向另一只眼睛呈现正交方向会对图谱关系产生的影响。由于方向偏好和眼优势现在紧密耦合，人们可能会预期方位和眼优势轮廓会失去通常的正交关系，而是彼此平行。然而，令人惊讶的是，该模型预测在这种情况下，正交交叉有时可以保留。该模型还预测，方位涡旋可以从眼优势柱的中心迁移到边界，并且眼优势和方位图谱的波长可以耦合。这些预测为进一步测试维度减少原则在解释受干扰和正常养育条件下的图谱结构的充分性提供了一种方法，从而使我们能够加深对视觉环境对视觉皮层发育影响的理解。
