Schott G D
The National Hospital for Neurology and Neurosurgery, London, UK.
Philos Trans R Soc Lond B Biol Sci. 2000 Dec 29;355(1404):1789-99. doi: 10.1098/rstb.2000.0735.
For over a century the arrow has appeared in illustrations of cerebral function, yet the implications of using such symbols have not been previously considered. This review seeks to outline the nature, evolution, applications and limitations of this deceptively simple graphic device when it is used to picture functions of the brain. The arrow is found to have been used in several different ways: as a means of endowing anatomical structures with functional properties; as a method of displaying neural function either in free-standing form or in a structural or spatial framework; as a device for correlating functional data with underlying brain topography; and as a technique for linking functions of the brain with the world outside and with various philosophical concepts. For many of these uses the essential feature of the arrow is its directional characteristic. In contrast to the line, it is direction that enables the arrow to display information about time, which in turn can be exploited to depict functional rather than structural data. However, the use of the arrow is fraught with difficulties. It is often unclear whether an arrow has been used to illustrate fact, hypothesis, impression or possibility, or merely to provide a decorative flourish. Furthermore, the powerful symbolic nature of the arrow can so easily confer a spurious validity on the conjectural. Increasingly now there are insuperable difficulties when attempting to illustrate complex mechanisms of brain function. In the iconography of cerebral function, therefore, arrows with all their ambiguities may in certain circumstances become superseded by more non-representational symbols such as the abstract devices of the computational neuroscientist.
一个多世纪以来，箭头一直出现在脑功能的图示中，但使用这类符号的含义此前从未被探讨过。这篇综述旨在概述这种看似简单的图形工具在用于描绘大脑功能时的本质、演变、应用及局限性。人们发现箭头有多种不同的用法：作为赋予解剖结构功能特性的一种方式；作为以独立形式或在结构或空间框架中展示神经功能的一种方法；作为将功能数据与潜在脑地形图相关联的一种手段；以及作为将大脑功能与外部世界及各种哲学概念相联系的一种技术。对于这些用途中的许多而言，箭头的基本特征是其方向性。与线条不同，正是方向使箭头能够展示有关时间的信息，进而可被用于描绘功能而非结构数据。然而，箭头的使用充满困难。通常不清楚一个箭头是用于说明事实、假设、印象或可能性，还是仅仅为了起到装饰作用。此外，箭头强大的象征性质很容易赋予推测一种虚假的正确性。如今，在试图描绘复杂的脑功能机制时，越来越存在难以克服的困难。因此，在脑功能的图像学中，带有所有这些模糊性的箭头在某些情况下可能会被更具抽象性的符号所取代，比如计算神经科学家使用的抽象工具。
