Supramodal neural information supports stimulus-driven attention across cortical levels

Abstract

AbstractSensory systems utilise stimulus-driven attention to survey the environment for significant features. The question arises: are the cortical networks that influence stimulus-driven attention supramodal or specific to each sensory modality? Here we employed a hierarchical target detection task (n=30), examining cortical responses linked to the detection of salient targets in the somatosensory and auditory modality. In a temporal decoding analysis, we reveal a transient early supramodal process activated by target detection. We also demonstrate that both common and unique modulations of salience-related cortical responses to somatosensory and auditory targets involve modality-specific and frontal regions using Parametric Empirical Bayes. Specifically, we found that the inferior frontal gyri share information across both sensory modalities, while recurrent information transfer between ipsilateral inferior frontal gyri and associative regions was modality-specific. Finally, we showed both supramodal and modality-specific attentional modulations of effective connectivity linking regions across hierarchical levels in the cortex. Our results provide evidence for an attention network which integrates information across inferior frontal cortices to detect salient targets irrespective of their specific sensory modality. Beyond the notion of a supramodal attention system, our findings support the role of modality-specific cortices in processing inputs from other sensory modalities, highlighting that attention can bias these processes at multiple stages of the cortical hierarchy.Author summaryA key task of the brain is to deploy attention to detect important sensory events in its environment. How does the brain coordinate information from different senses when a sensory event pops out from the environment? Here we designed a nested oddball paradigm in which expectations about somatosensory and auditory stimuli are violated while high-density EEG is recorded. We also varied the extent to which the odd stimulus pops out from its sensory environment. Using temporal decoding, we reveal a supramodal short-lived cortical process when salient targets are detected. In an effective connectivity analysis, we also show that the detection of salient targets relies on a common interhemispheric inhibition between inferior frontal gyri. Beyond that, there are supramodal and modality-specific changes in effective connectivity linking associative and modality-specific regions in the cortex. Our results support a rapid and short-lived supramodal process in a distributed saliency detection system extending across the cortical hierarchy.