Neural mechanisms of spatial attention in the cat

Spatial attention is an important biological tool that helps animals to ori ent in their environment as well as to detect food and predators. We have i nvestigated the neural basis of attentional mechanisms with a combined appr oach of behavioral testing, 'virtual lesion' techniques and computational m odeling. Cats with unilateral deactivations of either posterior parietal cortex or t he superior colliculus exhibited a robust hemineglect for all novel visual stimuli presented in the contralateral space. Bilateral deactivation of the same neural structures, however, led to restoration of spatial attentional behavior. A simple mathematical model, based on known cortical and midbrai n connectivity of the cat, was used to simulate the neural mechanisms under lying intact, unilaterally impaired and bilaterally restored attentional be havior, as well as to produce predictions for further experiments. Our resu lts outline the contributions of cortical and subcortical stations to atten tion-guided behavior, and characterize functional interactions between stru ctures in either half of the brain. (C) 2001 Elsevier Science B.V. All righ ts reserved.