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Spreading Depression (SD) was first observed by Leao in 1944. It is a slowly traveling wave phenomenon elicited in the cortex of various brain structures in many different animals. It is characterized by depression of electroencephalographic activity. The wave is accompanied by increased blood flow and is followed by a period of vasodilation. The wave propagates with a speed of 1-15 mm/min. SD is believed to be the underlying physiological process that causes is migraine with aura.  The various factors affecting SD are ionic currents, pumps, neurotransmitters, spatial buffering, and osmosis. We consider the previous model of SD by Shapiro (2000) and try to simplify his complex model. We then will introduce additional factors that are believed to affect SD and build a new model. The model consists of  nonlinear partial differential equations which are to be solved numerically.