Figure 7.

Single cells possess an intrinsic controller structure with characteristics resembling PCP. (a) A schematic illustrating the concept of PCP using the analogy of magnetic domains. Ferromagnetic materials contain domains within which the magnetic orientations are aligned (indicated by the arrows). The overall random pattern of orientations (left) could be modified by the application of external forces, such as magnetic fields, or temperature forcing it to assume non-random shapes (right). (b) Likewise, the application of a target gradient-like pattern (Figure 5) enables machine-learning to organize the initially random intrinsic controller weights into PCP-like patterns over phylogenetic timescales. Specifically, the three anterior controller weights (blue) that control the anterior GJ and the three posterior controller weights (red) that control the posterior GJ of a single cell were randomly initialized in the interval [−1, 1] during the training. At the end of training, the anterior and posterior controller weights of the representative model culminated with categorically distinct values, the anterior set positive and the posterior negative, giving the cell a character of polarity. The inset shows a blow-up of a single cell together with its intrinsic controller (Figure 2).