Role of Mechanical Factors in the Morphology of the Primate Cerebral Cortex
Figure 2
Three Types of Trajectories of Corticocortical Projections
The diagram shows straight (st; thick solid line), intermediate (im; intermediate dashed line), and curved (cu; thin dashed line) projections that link a tracer injection site (dark spot) with different areas, shown in a coronal section through the rhesus monkey prefrontal cortex. The curvature (c) of the trajectories is determined by the relation c = d/x, in which x is the minimum distance (in 3-D Euclidean space) between projection origin and termination, and d the maximum deviation of the actual projection from the minimum distance path. These measures are indicated for examples of curved and intermediate projections, resulting in curvatures of ccu = 0.71 and cim = 0.26. Since the trajectory of the straight projection follows the minimum distance path, its curvature is zero. The thickness of the projections depicts the posited link between connection density and axonal trajectory. Axes of section: medial is to the left; dorsal, top.