Where is notification centre for Windows 8.1?

I am very happy to see notification centre for Windows Phone 8.1. However, where is notification centre for Windows 8.1? Have not seen anybody talking about it. It seems Microsoft is focusing more on Start Menu and floating Metro apps in their next update. No talk about Cortana on Windows 8.1 either, very strange.

Notification centre would be immensely helpful for the missed notifications of the Metro tiled apps. What do you think?