On the spread of spatial attention in touch: Evidence from event-related brain potentials

To investigate the distribution of tactile spatial attention near the current attentional focus, participants were cued to attend to one of four body locations (hand or shoulder on the left or right side) to respond to infrequent tactile targets. In this Narrow attention task, effects of spatial attention on the ERPs elicited by tactile stimuli delivered to the hands were compared as a function of the distance from the attentional focus (Focus on the hand vs. Focus on the shoulder). When participants focused on the hand, attentional modulations of the sensoryspecific P100 and N140 components were followed by the longer latency Nd component. Notably, when participants focused on the shoulder, they were unable to restrict their attentional resources to the cued location, as revealed by the presence of reliable attentional modulations at the hands. This effect of attention outside the attentional focus was delayed and reduced compared to that observed within the attentional focus, revealing the presence of an attentional gradient. In addition, to investigate whether the size of the attentional focus modulated the effects of tactile spatial attention on somatosensory processing, participants also completed the Broad attention task, in which they were cued to attend to two locations (both the hand and the shoulder) on the left or right side. Attentional modulations at the hands emerged later and were reduced in the Broad compared to the Narrow attention task, suggesting reduced attentional resources for a wider attentional focus.

Automated summary

This study investigated the distribution of tactile spatial attention around the current attentional focus. Participants were cued to attend to different body locations and response to infrequent tactile targets. It was found that when participants focused on the hand, attention modulated the sensory-specific P100 and N140 components, followed by a longer latency Nd component. However, when participants focused on the shoulder, attentional resources were unable to be restricted to the cued location, indicating an attentional gradient. Additionally, the size of the attentional focus affected the effects of tactile spatial attention, with reduced attentional resources for a wider attentional focus observed.