Neuropsychologia 43 (2005) 2041–2056 A functional MRI study of preparatory signals for spatial location and objects Maurizio Corbetta a,b,c,∗ , Aaron P. Tansy b , Christine M. Stanley b , Serguei V. Astafiev b , Abraham Z. Snyder a,b , Gordon L. Shulman a a Department of Neurology, Washington University School of Medicine, East Building, 4525 Scott Ave., Box 8225, St. Louis, MO 63110, USA b Department of Radiology, Washington University School of Medicine, East Building, 4525 Scott Ave., Box 8225, St. Louis, MO 63110, USA c Department of Anatomy and Neurobiology, Washington University School of Medicine, East Building, 4525 Scott Ave., Box 8225, St. Louis, MO 63110, USA Received 31 August 2004; received in revised form 8 March 2005; accepted 18 March 2005 Available online 26 April 2005 Abstract We investigated preparatory signals for spatial location and objects in normal observers using functional magnetic resonance imaging (fMRI). Activity for attention-directing cues was separated from activity for subsequent test arrays containing the target stimulus. Subjects were more accurate in discriminating a target face among distracters when they knew in advance its location (spatial directional cue), as compared to when the target could randomly appear at one of two locations (spatial neutral cue), indicating that the spatial cue was used. Spatially specific activations occurred in a region at the intersection of the ventral intraparietal sulcus and transverse occipital sulcus (vIPS- TOS), which showed significantly stronger activation for rightward- than leftward-directing cues, while other fronto-parietal areas were activated by the cue but did not show spatial specificity. In visual cortex, activity was weak or absent in retinotopic occipital regions following attention-directing cues and this activity was not spatially specific. In a separate task, subject discriminated a target outdoor scene among distracters after the presentation of spatial neutral cues. There was no significant difference in dorsal frontoparietal activity during the face versus scene discrimination task. Also, there was only weak evidence for selective preparatory activity in ventral object-selective regions, although the activation of these regions to the subsequent test array did depend upon which discrimination (face or place) was performed. We conclude first that under certain circumstances, spatial cues that produce strong behavioral effects may modulate parietal-occipital regions in a spatially specific manner without producing similar modulations in retinotopic occipital regions. Second, attentional modulations of object-selective regions in temporal-occipital cortex can occur even though preparatory object-selective modulations of those regions are absent or weak. © 2005 Elsevier Ltd. All rights reserved. Keywords: Faces; Places; Attention; Parietal; Frontal; Visual cortex 1. Introduction When looking at a visual scene, we can focus attention on the location or the identity/features of objects (e.g. whether it is a face or a building), and both forms of selection may occur during normal vision. A growing number of brain imaging studies have implicated a set of dorsal frontoparietal areas, including the putative human homologues of monkey areas ∗ Corresponding author. Tel.: +1 314 362 7620; fax: +1 314 362 6110. E-mail address: mau@npg.wustl.edu (M. Corbetta). LIP and FEF in the control of visual attention (reviewed in Corbetta & Shulman, 2002; Kanwisher & Wojciulik, 2000; Pessoa, Kastner, & Ungerleider, 2003). Activity in these areas is time-locked to the onset of cue stimuli that instruct subjects to direct and maintain attention to a location, or switch atten- tion between locations, features, or whole objects (Corbetta, Kincade, Ollinger, McAvoy, & Shulman, 2000; Hopfinger, Buonocore, & Mangun, 2000; Kastner, Pinsk, De Weerd, Desimone, & Ungerleider, 1999; Liu, Slotnick, Serences, & Yantis, 2003; Shulman et al., 1999; Yantis et al., 2002). It has been proposed that these areas selectively bias visual cor- 0028-3932/$ – see front matter © 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.neuropsychologia.2005.03.020