Judging faces is not a tricky business. When looking for beauty, for example, we naturally favour symmetric faces. What goes behind the face, though, is a different matter, as our brains are markedly asymmetric.
Thinking about brain asymmetry quickly brings to mind the classic studies of Broca, Wernicke and Sperry. But in addition to functional differences between the left and right hemispheres, anatomical asymmetries are also abundant in our nervous system, as Arthur Toga and Paul Thompson discuss in this issue (page 37). Some of these asymmetries are quite marked. For example, the Yakovlevian torque — a protrusion of the right frontal and left occipital lobes over their contralateral counterparts — makes the human brain look as if it has been twisted. Other asymmetries, such as the positions of specific sulci, are so subtle that they remain a matter of debate. In this regard, the development of new imaging techniques provides us with an unprecedented level of analysis that will make it possible to determine unequivocally our degree of brain asymmetry and, coming full circle, to understand its functional significance.
