Cytoarchitectonic mapping of attentional selection and reorienting in parietal cortex.
Gillebert CR., Mantini D., Peeters R., Dupont P., Vandenberghe R.
Selection and reorienting are two fundamental aspects of spatial attention. By means of event-related fMRI in a total of 26 subjects, we localized these two processes within a same experiment applying a probabilistic cytoarchitectonic reference frame. In a classical spatial cueing paradigm, the target was presented at the cued location either alone (60% of trials) or in combination with a contralateral distracter ('competition trials', 20% of trials), or at a location opposite to the cued location ('invalidly cued trials', 20% of trials). In a sensory control experiment we differentiated between the attentional and the sensory effects of the distracter. In areas hIP1 and hIP3, competition trials exerted a significantly stronger attentional effect than invalidity trials. Conversely, area PF in the right hemisphere showed an invalidity effect in the absence of competition effect. A third type of response was found in areas PFm and PGa which showed both an invalidity and a competition effect. The combined study of selection and reorienting using a cytoarchitectonic reference frame enabled us to resolve the wide between-study variance in temporoparietal coordinates associated with the invalidity effect. Furthermore, the study demonstrated within a same experiment a functional dissociation between reorienting and selection in parietal cortex.