VISUOSPATIAL ATTENTION IN THE RAT AND POSTERIOR PARIETAL CORTEX LESIONS

Covert attention to visuospatial stimuli was assessed in rats using a modified version of a task designed for human subjects. Rats were trai ned to respond toward bright target lights presented to the right or l eft visual space. Dim cue Lights served to attract their attention pri or to the onset of the bright target lights. Consistent with previous research using similar paradigms, rats in this experiment displayed lo nger reaction times during trials in which the cue and target lights w ere presented on opposite sides of visual space. Throughout pre- and p ost-operative testing, individual subjects showed lateralized differen ces in the performance of this task as indicated by asymmetries in rea ction time, the percentage of correct responses, and the number of res ponses made to each side of visual space (response bias). Lesioning th e area of cortex thought to be a possible homolog of the posterior par ietal cortex in primates produced no specific effects on performance. It is suggested that this paradigm may tap into an evolutionarily cons erved attentional process, but that this process may be subserved by s omewhat different neural structures in different species.