Memsic accelerometer in Matlab

I have been playing around with the Memsic accelerometer on my arduino duemilanove board. Using the IDE and the code posted in the Wiki I can get everything working great. Now I am moving to Matlab. Im got all the libraries there and working so I can connect to the Arduino board from Matlab and read and write data. My question lies with really the pulseIn() function that the code for the IDE uses. How do this convert to code for Matlab?