EFFORTFUL INFORMATION-PROCESSING IN A SPONTANEOUS SPATIAL SITUATION BY RATS WITH MEDIAL PREFRONTAL LESIONS

Previous research has suggested that the rat prefrontal cortex might p lay a role in spatial information processing and in divided attention. More recent work showed that the effect of prefrontal lesions is more important when the task involves response selection in complex situat ions. The first aim of the present study was to test the effect of les ions of the prelimbic area of the rat prefrontal cortex in spatial exp loration, a situation involving the processing of spatial and non-spat ial information, but requiring no response selection. The second aim w as to manipulate the degree of cognitive effort required by the task. The latter effect was tested by manipulating the number of items to ex plore. Rats explored either a simple (3 objects) or a complex (6 objec ts) situation. We reasoned that acquiring spatial information so as to react adequately to spatial or non spatial changes involved more effo rtful processing in the complex situation than in the simpler one. The results suggest that the medial prefrontal cortex is not crucially in volved in effortful processing when the task requires no response sele ction.