Building a modeling capability for a physical phenomenon using differential equations is central to chemical engineering professionals. Using functional magnetic resonance imaging (fMRI), this work for the first time measures brain activities in partial differential equation reading and joke reading by selected professionals. Experimental results demonstrate that the equation message is first processed by the primary visual cortex (V I), and is then sent to Brodmann area 7 for information integration, and Broca's area (Brodmann area 44), Wernicke's area, and the fusiform gyrus to interpret its abstract meaning. The brain handles the differential equation as a syllabary rather than a character, and remembers the equation based on its shape rather than its identity. (c) 2008 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.