In this paper, we propose a mechanism which the neocortex may use to store sequences of patterns. Storing and recalling sequences are necessary for making predictions, recognizing time-based patterns and generating behaviour. Since these tasks are major functions of the neocortex, the ability to store and recall time-based sequences is probably a key attribute of many, if not all, cortical areas. Previously, we have proposed that the neocortex can be modelled as a hierarchy of memory regions, each of which learns and recalls sequences. This paper proposes how each region of neocortex might learn the sequences necessary for this theory. The basis of the proposal is that all the cells in a cortical column share bottom-up receptive field properties, but individual cells in a column learn to represent unique incidences of the bottom-up receptive field property within different sequences. We discuss the proposal, the biological constraints that led to it and some results modelling it.