Superficial layers of mouse primary somatosensory cortex showing apical dendrites of L5 pyramidal neurons labeled with a cyan fluorescent protein (CFP)-cell fill, and excitatory post-synaptic sites marked by PSD95.FingR-Citrine (yellow). Higherorder thalamic (posterior medial nucleus, POm) axons innervating L1 are labeled with tdTomato (red) to enable digital detection of thalamocortical synapses onto L5 dendrites. For more information, see the article by Ray et al. (pages 584–600). Cover image: Ajit Ray.