Rats trained under unilateral cortical spreading depression on a brightness discrimination task for water reinforcement will show little or no transfer when retrained with the contralateral cortex depressed. The current study was performed in order to determine if the degree of transfer can be affected by reinforcement or motivational variables. Rats were trained on a brightness discrimination task to either escape or avoid painful foot shock. The animals trained to Escape showed nearly perfect transfer. The animals trained to avoid showed very little transfer of the avoidance response but did transfer the brightness discrimination. It was concluded that in the unilateral spreading depression paradigm the degree of transfer obtained on similar tasks is altered by changing the reinforcement. Cortical spreading depression Brightness discrimination Interhemisphcric transfer Avoidance conditioning Escape conditioning