Previously reward-associated stimuli capture spatial attention in the absence of changes in the corresponding sensory representations as measured with MEG.
Tankelevitch L., Spaak E., Rushworth M., Stokes MG.
Studies of selective attention typically consider the role of task goals or physical salience, but attention can also be captured by previously reward-associated stimuli, even if they are currently task-irrelevant. One theory underlying this value-driven attentional capture (VDAC) is that reward-associated stimulus representations undergo plasticity in sensory cortex, thereby automatically capturing attention during early processing. To test this, we used magnetoencephalography to probe whether stimulus location and identity representations in sensory cortex are modulated by reward learning. We furthermore investigated the time-course of these neural effects, and their relationship to behavioural VDAC. Male and female human participants first learned stimulus-reward associations. Next, we measured VDAC in a separate task by presenting these stimuli in the absence of reward contingency, and probing their effects on the processing of separate target stimuli presented at different time lags. Using time-resolved multivariate pattern analysis, we found that learned value modulated the spatial selection of previously rewarded stimuli in posterior visual and parietal cortex from ∼260ms after stimulus onset. This value modulation was related to the strength of participants' behavioural VDAC effect and persisted into subsequent target processing. Importantly, learned value did not influence cortical signatures of early processing (i.e., earlier than ∼200ms), nor did it influence the decodability of stimulus identity. Our results suggest that VDAC is underpinned by learned value signals which modulate spatial selection throughout posterior visual and parietal cortex. We further suggest that VDAC can occur in the absence of changes in early visual processing in cortex.Significance statementAttention is our ability to focus on relevant information at the expense of irrelevant information. It can be affected by previously learned but currently irrelevant stimulus-reward associations, a phenomenon termed "value-driven attentional capture" (VDAC). The neural mechanisms underlying VDAC remain unclear. It has been speculated that reward learning induces visual cortical plasticity which modulates early visual processing to capture attention. Although we find that learned value modulates spatial signals in visual cortical areas, an effect which correlates with VDAC, we find no relevant signatures of changes in early visual processing in cortex.