Neuroscientist Tomas Knapen from the University of Amsterdam (UvA) has succeeded in using an fMRI scanner to map the brain processes at the moment when a person’s perception or interpretation changes. This new research shows that changes of consciousness occur 'more automatically' than previously thought. The UvA researcher conducted this research with Jan Brascamp from Vanderbilt University and other colleagues in the Netherlands, Australia and the United States. The results have been published today in The Journal of Neuroscience.
We experience our consciousness as a constant stream of impressions, thoughts, plans and actions. Our brains are constantly busy interpreting the information that comes through our eyes. We frequently change our interpretation; for example, if you look at the Necker cube (see picture). Looking at the base of the cube, you initially see the spatial orientation in one direction. This changes after a short space of time, and your conscious perception of the cube ‘flips’.
The researchers wanted to see if such a flip occurs automatically in the visual brain, or if it is actually a higher-order process where mechanisms which we control, such as attention, play a major role. Knapen did this by using an fMRI scanner to look at the brain activity ocurring during a re-interpretation, such as when looking at a Necker cube.
It was previously thought that the higher-order, attention-related brain activity caused such a reinterpretation, but the research conducted by Knapen and his colleagues shows that much of this activity is probably only a response to such a change. They imitated the flips on a screen by through creating a video animation of the test subjects’ perception which is as true-to-life as possible. It appeared that the attentional processes in the higher brain areas respond exactly the same as during a flip generated in the brain itself. These new results seem to show that lower brain processes autonomously trigger the reinterpretation.
This implies that the change in consciousness is a more basic process than previously believed. Our consciousness therefore functions ‘more automatically’ than formerly thought.
Tomas Knapen, Jan Brascamp, Joel Pearson, Raymond van Ee and Randolph Blake. ‘The role of frontal and parietal brain areas in bistable perception.’ The Journal of Neuroscience (July 2011).