Do structural brain differences underlie perceptual differences?

From March-December 2010 I was an intern in the research group of Floris de Lange at the Donders Institute. I carried out two projects: one on structural brain differences and perceptual differences and one on the role of awareness in response priming. You can read the resulting article of the second project in another post.

With the first project we wanted to answer the question of how differences between people in their perception of the world depend on their brain structure. In particular, we wanted to look at the structural (white matter) and functional connectivity between sensory areas.

One of the tasks we used to assess subjects’s perception was the ‘McGurk task’. In this task, you see and simultaneously hear someone saying a syllable. However, the auditory and visual information are incongruent, and as a result some people perceive a ‘fused’ new percept. Here is a BBC video in which the McGurk effect is demonstrated. We hypothesized that people who perceive more fused percepts may have stronger connected auditory and visual cortices, since the two sensory signals must be integrated into one percept by combining the information from both areas. 

We have not analyzed all the data yet, but we will give you an update on the results in a while.