Propagation of BOLD Activity Reveals Task-dependent Directed Interactions Across Human Visual Cortex

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Large-scale blood-oxygen-level-dependent (BOLD) activity propagation is linked to anatomical connections and behavioral state transitions.
• The relationship between BOLD activity propagation and local brain anatomical structure remains less understood.

Purpose of the Study:

• To investigate if BOLD activity propagation relates to local anatomical structure in early visual areas (V1, V2, V3).
• To characterize the influence of local activity and directed interactions on BOLD propagation patterns.

Main Methods:

• A noise-diffusion network modeling approach was used to estimate effective connectivity (EC) and cortical excitability.
• The model aimed to reproduce the spatiotemporal covariance structure of BOLD signals.
• Data from 7T fMRI recordings during resting state (RS) and visual field mapping (VFM) were analyzed.

Main Results:

• Distinct EC interactions and altered cortical excitability were observed between RS and VFM conditions.
• A reconfiguration of feedforward and feedback interactions across the visual system was identified.
• BOLD activity propagation patterns varied depending on the task.

Conclusions:

• BOLD activity propagation is functionally relevant, reflecting directed neuronal interactions.
• Task-dependent changes in cortical excitability influence BOLD signal propagation.
• The study provides insights into the local-scale organization of BOLD activity in the visual cortex.