The laterodorsal tegmentum (LDT) is a brain structure involved in distinct behaviors including arousal, reward, and innate fear. How environmental stimuli and top-down control from high-order sensory and limbic cortical areas converge and coordinate in this region to modulate diverse behavioral outputs remains unclear. In this issue, Wang et al. applied monosynaptic retrograde tracing to the whole brain to identify the cell type-specific nuclei upstream of the LDT . In the cover image, the brain is like a universe in which the LDT nucleus is not only well organized in an elegant hierarchy, but also makes fascinatingly complex connections with other nuclei. See pages 781-790. (Cover image provided by Dr. Hao Wang).