Transfer of brightness discrimination under unilateral spreading depression

Abstract

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

Interhemispheric transfer as a function of light intensity discrimination difficulty.

“…The graded IHT of intensity discriminations of increasing difficulty is consistent with the data of Bauer and Cooper (1964), Best and Hamburg (1969), Lashley (1929), Meikle and Sechzer (I960), and Trevarthen (1962) indicating that gross intensity discriminations can be learned subcortically, but not threshold intensity or pattern discriminations. The data of the present experiment are also consistent with the centrencephalic theory which Robert Thompson (1965) has elaborated to account for IHT of visual habits.…”

“…Spreading cortical depression (SD) has been used to investigate interhemispheric transfer (IHT) using the general paradigm of training the subject with one hemisphere depressed and testing for transfer with the contralateral hemisphere depressed. Results of numerous experiments have shown that the degree of IHT is a function of the kind of task employed (Best & Hamburg, 1969;Bures, Buresova, & Fifkova, 1964;Kukleta, 1966), the amount and kind of training between original learning and transfer testing (Russell & Ochs, 1961, 1963Travis, 1964), and the similarity of the stimulus conditions produced by SD between training and testing for IHT (Reed & Trowill, 1969;Schneider, 1967).…”