By hooking up an MRI and looking at the visual cortex whilst the subject looks at an object creates a pattern. When the subject recalls that object in short term memory, you can recognise that pattern and tell what object the subject is thinking of.

This has 2 implications:
1) We can read a specific person’s mind; if we build up a library of their memory patterns
2) The part of the brain used to recall memories is the same as the part used when we are looking at something directly. This is important: it means that we really are living in a world created by our imaginations 🙂