Greebles 

Hi, the "greebles" weren't computer generated nonsense figures, per se, but sets of stimuli created to form different "races" or "kinds" of greebles noticeable only by experts. Greebles themselves did not activate the fusiform in anyone, but only in Greeble experts. That was the significant finding, that the fusiform was activated in greeble experts, but little activation in novices.

Oh, and sorry about sounding too academic, I paraphrased lines from my honours thesis!