An alternative hypothesis is focused more on the difference between the dorsal and ventral subregions and takes into consideration their functional separation. In this model, the PCC is hypothesized to take a chief regulatory role in focusing internal and external attention. Mounting evidence that the PCC is involved in both integrating memories of experiences and initiating a signal to change behavioral strategies supports this hypothesis. Under this model, the PCC plays a crucial role in controlling state of arousal, the breadth of focus and the internal or external focus of attention. This hypothesis emphasizes the PCC as a dynamic network, rather than a fixed and unchanging structure.