Later changes are not mentioned in changes.
Modifications are frequent.
It treats the cortex as a field or array of typically a few hundred areas called cortical columns, elements or just points. The array can have an arbitrary geometry defined by a file of couplings, or it can be an evenly spaced rectangular grid that is flat or bent into a cylinder or toroid. In the evenly spaced case, coupling and delay between elements are functions of the distance between them. Delay is proportional to distance. A cortical column is treated as a mass of excitatory neurones and a mass of inhibitory neurones with couplings between them.