Abstract
The neural activity for plan and execution of object directed actions is known to be modulated by object properties. It remains unknown whether the sensory processing of object properties is modulated by previously cued actions. We used a cue-separation task in a slow event-related fMRI design to investigate this question. In each trial, participants received two cues in two successive phases: an action cue (AC: auditory instruction to either ‘Grasp’ or ‘Align’ the hand with the visual cue) and a visual cue (VC: a 3D wooden rod illuminated for 250ms in two orientations). Each cue was followed by an 8 second delay in complete darkness. The second delay was followed by a go cue to execute the instructed movement toward the rod. The Align condition required participants to adjust the orientation of the hand according to the rod, while the Grasp condition required participants to position the digits according to the rod. We manipulated the order of cue presentation (AC:VC and VC:AC) as a control. Therefore, our design consisted of two action cues (Grasp and Align), two rod orientations (Horizontal and Vertical) and two cue orders (AC:VC and VC:AC). Fourteen right handed participants took part in this study. We hypothesized that action-cue dependant modulation of sensory activity during the delay following the visual cue would be reflected in different activity levels for the two action cues (Align and Grasp). We found that the calcarine sulcus, superior frontal sulcus (SFS), superior parietal occipital sulcus (SPOC), posterior intraparietal sulcus (pIPS) and anterior intraparietal sulcus (aIPS) showed higher activation for ‘Align’ than ‘Grasp’ cued action during the delay following visual presentation of the rod. These results suggest that the re-entrant feedback from the motor system influences visual processing even at early levels of cortical input.
Meeting abstract presented at VSS 2015