Neuron, Vol 50, 329-339, 20 April 2006
Goldberg et. el. argue that perceptual awareness seems not to engage areas associated with introspection. Problem for higher-order theories of consciousness?
Abstract: A common theme in theories of subjective awareness poses a self-related
“observer” function, or a homunculus, as a critical element without
which awareness can not emerge. Here, we examined this question using
fMRI. In our study, we compared brain activity patterns produced by a
demanding sensory categorization paradigm to those engaged during
self-reflective introspection, using similar sensory stimuli. Our
results show a complete segregation between the two patterns of
activity. Furthermore, regions that showed enhanced activity during
introspection underwent a robust inhibition during the demanding
perceptual task. The results support the notion that self-related
processes are not necessarily engaged during sensory perception and can
be actually suppressed.