Brain-wide information flow dynamics during novel visual processing in humans

The human brain’s capacity for visual information processing is essential for higher-order cognitive functions, including facial recognition and spatial navigation. However, the millisecond-scale dynamics of cortico-subcortical information flow during novel visual stimulation remain unclear. To investigate this, we conducted intracranial electroencephalography (iEEG) recordings in 22 patients with refractory epilepsy as they underwent a picture-viewing task. Our findings showed region-specific modulations in high-frequency broadband (HFB, 60–160 Hz) activity across multiple brain regions, such as the dorsal and ventral visual streams, the limbic system, and higher-order cortical areas. Initial activation followed a hierarchical, back-to-front propagation pattern, starting from the primary visual areas, progressing through the ventral and dorsal streams, and ultimately engaging high-order cortical and limbic structures. Extensive top-down connectivity from higher-order cortex to limbic areas further revealed their role in novel visual processing, providing a high-resolution spatiotemporal map of visual information flow across brain regions. Human intracranial recordings reveal millisecond-scale visual flow from occipital cortex along parallel dorsal and ventral pathways to frontal and limbic regions, with category-specific dynamics for faces and places during novel visual processing.