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Seeing is Believing

Tuesday 17th November 2009 @ 19:00

Non-Member: £12.00 ; Staff: £5.00 ; Student: £3.00


Professor Christopher Kennard, Nicolas Kurti Senior Fellow, Brasenose College, Oxford University

How does the brain achieve the remarkable feat of providing us with the full richness of our visual perception?

When we look at the world around us a large part of the brain processes the images received by our eyes. Within a fraction of a second, all the attributes of the scene - form, colour, motion, depth and much else besides - are each processed in separate but interconnected areas of the brain, which then somehow generates a unitary visual percept.

Professor Christopher Kennard used many intriguing demonstrations of visual illusions to explain how the normal brain interprets images. He showed how damage to different parts of the visual brain in patients after a stroke affect the brain's interpretation of what it sees. For example, some patients can identify patterns and shapes but not colour, whereas others are only unaware of movement, or fail to recognise familiar faces or objects. It became apparent that the visual brain often has to generate hypotheses to interpret the inputs from the visual scene, and this may lead to discrepancies between perception and reality, in turn? leading to what that scientific prophet Sir Francis Bacon described in his book The New Atlantis as "deceits of the sight"

Professor Kennard was previously Deputy Principal of the Faculty of Medicine and Head of Department of Clinical Neuroscience at Imperial College.

He has researched widely in the area of cognitive neuroscience and visual sciences using, in particular, the analysis of abnormalities of visual perception and eye movements in human neurological disease to further understanding of brain function. His research involves behaviourial studies on patients using a wide range of techniques including functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation and brain lesional mapping. Recently his reseach has focussed on the role of the frontal lobes in decision making with regard to movement, aspects of visual attention and the use of eye movements as pre symptomatic biomarkers in neuro degenerative disease.

Professor Kennard took his guiding quotation from Sir Francis Bacon's prophetic book New Atlantis, published in 1624, which describes an ideal country where "generosity and enlightenment, dignity and splendour, piety and public spirit" predominate. He also described machines, processes and phenomena of the future with extraordinary accuracy. This article written in 1941 in Modern Mechanix with accompanying comments gives some interesting insights into Sir Francis.

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