Title : The hierarchical spatiotemporal dynamics of the visual system in Macaques
Abstract:
The brain’s ability to process complex real-world phenomena relies on its operation across multiple timescales, which have been shown to be organized hierarchically across various brain regions. At present, the relation between the topography of intrinsic neural timescales (INT) and gradients of functional connectivity (FC) has not been investigated in the macaque visual system. In this study, we aim to investigate the relationship between functional magnetic resonance imaging (fMRI)-derived hemodynamic INTs, calculated by applying a voxel-wise autocorrelation function, and FC gradients in the visual system in an attempt to gain a complete understanding of the large-scale organization of the macaque brain. Using ultra-high field fMRI (10.5 T), we show that the distribution of INTs in visual areas V1 to V4 is organized along one dimension of high-dimensional FC topography. Furthermore, these correlations reflect the functional organization of visual processing pathways: specifically, in V1, an anterior-posterior axis; in V2 and V4, a ventro-dorsal axis, and in V3, a medial-lateral axis. Our findings demonstrate a significant voxel-wise correlation between INTs and FC gradients, highlighting the utility of high-resolution neuroimaging for elucidating brain function. This research advances the understanding of the hierarchical spatiotemporal dynamics in the visual cortex, with implications for studying neurological disorders and cognitive function in the visual areas.
Keywords: Intrinsic Neural Timescales, Functional Magnetic Resonance Imaging, Functional Connectivity, Visual System
