Delayed alternation learning in cats: implications for the interpretation of prefrontal symptoms.

Neurobehaviorists predominantly use certain kinds of tasks in combination with distinct cortical lesions (9, 18). For the prefrontal cortex, the most commonly favored problems are the delayed-reaction-type tasks (13-15, 17, 18). One form or these tasks-the (spatial) delayed-alternation (DA) task-requires the animal to alternate between two spatially separated cues and/or responses, whereby a delay is interposed between trials or between the cue-access and the response period (3, 13, 17, 35). The performance of DA tasks by rats, cats, dogs and monkeys was consistently impaired, moderately to severely, after lesioning the prefron-tal cortex or its distinct parts (13, 17, 18). However, in spite of the uniformity of a DA performance deficit after prefrontal lesions, no generally valid and accepted explanation has been found. Hypotheses presented include an impaired short-term memory (lo), or-more specifically-a short-term memory deficit for the spatial dimension (30), Though there exists evidence of a possible subgrouping of behavioral symptoms and prefrontal subregions (18, 33), the above mentioned examples have also been related to only one particular subarea, namely the dorsolateral prefrontal cortex of the monkey (18). However, as brain lesions not only include distinct changes with