The Ajna Center is how you think. A defined Ajna center has a fixed and reliable way in which it processes information. It can seem and feel certain of its opinions, concepts, and theories. It has a consistent way of conceptualizing, and sees information through the same patterns.
The undefined Ajna is under pressure to try to hold onto a mental opinion. With no fixed way of thinking, these people often end up with anxiety about not being consistent, and overcompensate by trying to make everyone else believe that they are certain and smart. The wisdom here is to see that there is no need to have a fixed mental opinion about anything. The open Ajna question is : “Am I trying to convince everyone/myself that I am certain?”