Op de Beeck, Wagemans and Vogels (2001) discovered that IT neurons represent low-dimensional configurations of parameterized abstract shapes. We have reported an event-related (ER) fMRI adaptation experiment (SFN 2004 abstract Program No. 664.8) which showed that the amount of recovery of adaptation in anterior LOC was monotonically related to the transformational distance between the two object contours in each trial. In the present ER-fMRI adaptation experiment we explicitly control for the number of unique stimulus repetitions to study additionally whether responses to prototypical shapes are lower than to less prototypical shapes, as suggested by recent single-cell recordings (Kayaert, Op De Beeck, Biederman and Vogels, 2004). For each of 8 categories, we started from the 4 extremes in a measured two-dimensional similarity space and created the 2 diagonal morph lines (0%-33%-66%-100%) resulting in 8 unique stimuli for each of the 8 categories. By pairing stimuli with themselves or with others from the ...