| Neural mechanisms underlying temporal modulation of visual perception. | ||||||
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(summary in Dutch / Samenvatting in het Nederlands) | ||||||
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A dance about my PhD project won the 2010 AAAS 'Dance Your PhD' contest of Science Magazine in the category Biology (watch on [Vimeo] and [YouTube]). |
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Click for [text explaining the dance] and [photos of rehearsals].
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However confident we feel about the way we perceive the visual world around us, there is not a one-to-one relation between visual stimulation and visual perception. Our eyes register reflections of the visual environment and our brain has the difficult task of constructing 'reality' from this information. My thesis describes how internal information - like perceptual memory and the resolvement of perceptual ambiguity - is associated with activations of sensory rather than cognitive brain regions. These sensory brain regions also process the external information captured by our eyes. This means that the way we interpret what we see is subjective, with internal and external information inextricably linked.
I found that the way we perceive an ambiguous image is partly determined by the way we have perceived it before [PDF] and that perceptual memory modulates brain activity directly after you see an image appear on the screen, before you have interpreted the image [PDF]. Perceptual memory alters activity in brain regions that are specialized for the type of image that was shown [PDF]. Recording brain activity from electrodes inside the human skull, I found that the occipital cortex is involved in the processing of visual illusions [PDF]. A journal club article dedicated to this publication said we “[put] the occipital cortex back in the spotlight” [PDF]. |
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Explanation of the dance: |
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| You are about to watch a video-clip... Visual information will be entering your brain. | |
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| At first the visual information in your brain is unorganized. There is a lot of information and it is a mess. | In an intelligent way the brain examines and organizes the information. | <
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| It is too much to experience everything there is to see. You will select only a small part of the information for conscious experience. | Then you are suddenly interrupted by a phone call and you forget about the video-clip for a moment. |
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| After the phone call you look at the video-clip again. Because your brain has remembered it the structuring of information will be fast and efficient. | The way you perceive the video-clip is modified by your memories. The memories stored in your brain interact with the visual information. |
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| The result: watching the video-clip is a vivid conscious experience you will not forget! | |
