300 µm multi-echo bSSFP fMRI at 7 Tesla revealed the IPS-V1 feedback circuit of spatial attention in the human brain

Motivation: Layer-specific response in frontoparietal areas and their connectivity with the visual cortex are important to understand the neural circuitry of attention. Goal(s): Investigate the neural circuitry of attention in IPS and V1 with laminar fMRI. Approach: Using ultra-high resolution multi-echo bSSFP fMRI at 7 Tesla, layer-specific functional activity in IPS and V1 were simultaneously recorded in a spatial attention task. Results: Attention demanding task induced significant activations in both superficial and deep layers of IPS, enhanced activity in the deep layers of V1, and increased feedback connectivity from the deep layers of IPS to the deep layers of V1. Impact: This study demonstrates the feasibility of using ultra-high resolution multi-echo bSSFP fMRI at 7 Tesla to simultaneously image multiple brain regions to investigate the neural circuitry of high-level cognition.