Abstract: PURPOSE: As the largest thalamic nucleus with extensive cortical connections, the pulvinar has long been recognized as a critical node in the attention network. However, the role of the pulvinar remains unclear in selective attention. The present study aimed to investigate the interaction between the pulvinar and V1 during selective attention and its contextual dependency.
METHODS: Using fMRI, we performed background connectivity between the pulvinar and V1 in relation to focused versus diffused attention allocation, in weak and strong visual crowding contexts. Furthermore, we utilized time-lagged connectivity and dynamic causal modelling (DCM) to examine the modulation effect of attention and context in the directional connectivity.
RESULTS: Our findings revealed that focused attention led to enhanced correlations between the pulvinar and V1. Notably, this modulation was initiated by the pulvinar, and the strength of the modulation was dependent on the saliency of the target.
CONCLUSIONS: We suggest that the pulvinar initiates information reweighting to V1 according to attentional demands. These results provide valuable insights on the intricate interplay between attentional processes in subcortical structures like the pulvinar, and cortical processing in the visual system.

Key words: attention, pulvinar, V1, retinotopic connectivity, fMRI, DCM