Professor Geraint Rees at the Wellcome Trust Centre for Neuroimaging at UCL is tackling what might seem to be the most daunting of all the big existential questions - the nature and threshold of consciousness. He has used fMRI to show that people's visual brain registers images they are unaware they have seen, because they were visible for too brief a period (a fraction of a second) for their conscious brain to become aware of them. This is therefore a neural representation of the unconscious in the visual cortex - showing us where in the brain we can register information without being aware of it.

The ability to think about our consciousness and debate its source is one of the traits that define humanity. Another is the high premium that humans, across the globe, place on art, beauty, love and happiness. A colleague of Professor Rees at UCL, Professor Semir Zeki, is using brain-imaging techniques to find out what is happening in our brains when we respond to or create, a work of beauty - be it art, music, literature or mathematics - or when we feel love. His work will give us deep insights into our human nature, who we are, and how we view ourselves.