Separate and overlapping mechanisms of statistical regularities and salience processing in the occipital cortex and dorsal attention network

• Published in: Human brain mapping 2023-12, Vol.44 (18), p.6439-6458
• Main Authors: Beffara, Bertrand, Hadj‐Bouziane, Fadila, Hamed, Suliann Ben, Boehler, C. Nico, Chelazzi, Leonardo, Santandrea, Elisa, Macaluso, Emiliano
• Format: Article
• Language: English
• Subjects: attention; Bias; Brain mapping; connectivity; Cortex (parietal); fMRI; Functional magnetic resonance imaging; Life Sciences; Neural networks; Neurons and Cognition; Occipital lobe; Salience; space; Statistical analysis; Statistics; vision
• ISSN: 1065-9471; 1097-0193
• DOI: 10.1002/hbm.26520

Attention selects behaviorally relevant inputs for in‐depth processing. Beside the role of traditional signals related to goal‐directed and stimulus‐driven control, a debate exists regarding the mechanisms governing the effect of statistical regularities on attentional selection, and how these are integrated with other control signals. Using a visuo‐spatial search task under fMRI, we tested the joint effects of statistical regularities and stimulus‐driven salience. We found that both types of signals modulated occipital activity in a spatially specific manner. Salience acted primarily by reducing the attention bias towards the target location when associated with irrelevant distractors, while statistical regularities reduced this attention bias when the target was presented at a low probability location, particularly at the lower levels of the visual hierarchy. In addition, we found that both statistical regularities and salience activated the dorsal frontoparietal network. Additional exploratory analyses of functional connectivity revealed that only statistical regularities modulated the inter‐regional coupling between the posterior parietal cortex and the occipital cortex. These results show that statistical regularities and salience signals are both spatially represented at the occipital level, but that their integration into attentional processing priorities relies on dissociable brain mechanisms. Our findings contribute to the debate concerning how statistical regularities affect attention control, here pointing to substantial differences compared to salience processing: while salience was associated primarily with local effects within the occipital cortex, statistical regularities engaged a combination of local occipital processing and occipito‐parietal interactions.