Low frequency activity from somatosensory thalamus propagates brain-wide and modulates top-down visual processing

Top-down/descending control is a critical stage in sensory processing that underlies numerous cognitive processes. Recent studies uncovered the prevalence of converging long-range networks across multiple sensory modalities as anatomical substrates that likely mediate sensory top-down control. Using an optogenetic fMRI technique that we recently developed to examine patterns of large-scale brain-wide interactions mediated by the somatosensory thalamo-cortical network, we demonstrated that propagating low frequency activity (~1Hz) underlying such interactions enhanced visual responses in the superior colliculus. This work presents a new approach to investigate the functional roles of top-down control and their underlying brain mechanisms.