The current overarching challenge in neuroscience is to establish an integrated understanding of the brain networks, particularly the spatiotemporal patterns of neural activities that give rise to functions and behavior. fMRI provides the most versatile neuroimaging platform for mapping large-scale activities in vivo. However, on its own, many important details of the underlying network activities remain unresolved. Here, we employed fMRI in combination with pulsed optogenetic stimulation paradigms to probe the spatiotemporal dynamics and functions of the well-defined topographically-organized somatosensory thalamo-cortical network. We reveal unique long-range propagation pathways that are dictated by distinct neural activity temporal patterns initiated from the thalamus.