Medial frontal cortex mediates perceptual attentional set shifting in the rat

If rodents do not display the behavioral complexity that is subserved in pr imates by prefrontal cortex, then evolution of prefrontal cortex in the rat should be doubted. Primate prefrontal cortex has been shown to mediate shi fts in attention between perceptual dimensions of complex stimuli. This stu dy examined the possibility that medial frontal cortex of the rat is involv ed in the shifting of perceptual attentional set. We trained rats to perfor m an attentional set-shifting task that is formally the same as a task used in monkeys and humans. Rats were trained to dig in bowls for a food reward . The bowls were presented in pairs, only one of which was baited. The rat had to select the bowl in which to dig by its odor, the medium that filled the bowl, or the texture that covered its surface. In a single session, rat s performed a series of discriminations, including reversals, an intradimen sional shift, and an extradimensional shift. Bilateral lesions by injection of ibotenic acid in medial frontal cortex re sulted in impairment in neither initial acquisition nor reversal learning. We report here the same selective impairment in shifting of attentional set in the rat as seen in primates with lesions of prefrontal cortex. We concl ude that medial frontal cortex of the rat has functional similarity to prim ate lateral prefrontal cortex.