Sensory neglect in a frog: evidence for early evolution of attentional processes in vertebrates.

Mammalian-like 'sensory neglect' phenomena were elicited in Xenopus laevis by unilateral telencephalic lesion: after damage of the caudal striatum response rate to contralateral water waves was significantly lower than to ipsilateral ones. Response accuracy, however, was not affected. Within 6-8 weeks, animals recovered from neglect of unilateral stimuli; but simultaneous bilateral stimulation revealed an enduring neglect of contralateral stimuli. Latencies during acute neglect were significantly higher than after recovery. These results suggest that the neural mechanisms of selective attention might have evolved earlier than thought so far.