Crossmodal spatial attention between nociception and vision

Adequately reacting to a harmful stimulus requires to locate which part of the body is actually hurt and where is this stimulus in the environment. A cross-modal link between sensory modalities is thus necessary to coordinate spatial attention across the different dimensions in space. The aim of this study is to investigate, using event-related potentials (ERPs), how nociceptive stimuli applied to one hand are able to direct attention in external space and prioritize the processing of visual stimuli occurring close to the stimulated hand. Nociceptive stimuli were applied to either hand, and were shortly followed by a visual stimulus close to either the same hand (congruent) or the opposite hand (incongruent). The spatial congruency between the nociceptive and visual stimuli was not predictable. Participants were asked to detect rare targets in the series of visual stimuli. Results showed that reaction times to visual targets were not affected by the cross-modal spatial congruency. Conversely, preliminary analyses revealed that spatially congruent visual stimuli elicited ERPs with an enhanced negativity in the 220-380 time window, as compared to ERPs elicited by incongruent visual stimuli. This negativity could reflect cortical mechanisms to link spatial attention between one particular body limb and its peripersonal space.