The negative shift of DC potential was associated with an increase of extracellular potassium and energy metabolism. Therefore this dramatic phenomenon following the trauma to the brain was thought to be identical to spreading depression. 1. Spreading depression was most frequently observed between one and two hours after injury. 2. Spreading depression can be elicited in the deep structures as well as in the cortex. The more severe the injury, the more frequently the negative shifts were observed. The DC index seems to correlate well with the severity of the experimental model. It is concluded that the energy metabolism after the brain contusion was different from structure to structure and was changing continuously in the course of time.