Fig. 2: Brain-wide MOp-ul projection patterns by layer and class.
a, Key shows tracer types, mouse lines and layer and projection class selectivity for Cre driver lines used to label axons from MOp neurons. Numbers in brackets represent the number of tracer injection experiments per type. Symbols and colour code are used in b–d. b, Injection sites are plotted on a top-down view of the right cortical hemisphere from CCFv3 with the MOp-ul delineation from Fig. 1 in white. Distance between injection sites is 443.0 ± 185.04 μm (mean ± s.d.). c, A directed, weighted connectivity matrix (15 × 628) from MOp to 314 ipsilateral and 314 contralateral targets for each of the fifteen mouse lines or tracers listed in a. Each row shows the fraction of the total axon measured from a single experiment or the average when n > 1. Rows are ordered by major brain division. For AAV1-Cre monosynaptic tracing, known reciprocally connected regions are coloured grey. We performed hierarchical clustering with Spearman rank correlations and complete linkages, splitting the resulting dendrogram into four clusters. AAV1-Cre was not included in the clustering owing to the many excluded regions. A subset of target regions is indicated. The colour map ranges from 0 to 0.01 and the top of the range is truncated. d, Schematic summarizing all major MOp outputs by area, layer and projection class on a whole-brain flat map (Extended Data Fig. 14). ACB, nucleus accumbens; AUD, auditory area; BAC, bed nucleus of the anterior commissure; CB, cerebellum; cc, corpus callosum; CLA, claustrum; DN, dentate nucleus; ENTl, entorhinal area, lateral part; FN, fastigial nucleus; GP, globus pallidus; GRN, gigantocellular reticular nucleus; GU, gustatory areas; HY, hypothalamus; HPF, hippocampal formation; IO, inferior olivary complex; IP, interposed nucleus; IRN, intermediate reticular nucleus; IZp, spinal cord intermediate zone; MARN, magnocellular reticular nucleus; MDRNd, medullary reticular nucleus, dorsal part; MOp-ll, primary motor area, lower limb; MOp-tr, primary motor area, trunk; OLF, olfactory areas; ORB, orbital area; PL, prelimbic area; POST, postsubiculum; PPN, pedunculopontine nucleus; PRNc, pontine reticular nucleus, caudal part; RE, nucleus of reuniens; RR, midbrain reticular nucleus, retrorubral area; SCm, superior colliculus medial zone; sp, spinal cord; SI, substantia innominata; SNr, substantia nigra, reticular part; SPVO, spinal nucleus of the trigeminal, oral part; SSp-ll, primary somatosensory area, lower limb; SSp-m, primary somatosensory area, mouth; SSp-tr, primary somatosensory area, trunk; STN, subthalamic nucleus; TTd, taenia tecta, dorsal; VTA, ventral tegmental area; ZI, zona incerta.
