Viscerotopic organization of Layer V output neurons in M1 and M2 that influence sympathetic control of the stomach or kidney. Each colored square represents a single neuron labeled by retrograde transneuronal transport of RV from the stomach (blue) or kidney (yellow). The kidney data were taken from Levinthal and Strick (15). The data are overlaid on maps of motor representation in M1 and M2 (for details, see ref. 15). Although the two groups of labeled neurons show considerable overlap, the peak density of Layer V neurons that influence the stomach (circle with blue square) is slightly rostral and lateral to the peak density of Layer V neurons that influence the kidney (circle with yellow square). FL, forelimb; HL, hindlimb; J/F, jaw/face; M, medial; N, neck; R, rostral; T, trunk; T/HL, trunk/hindlimb overlap zone; V/FEF, vibrissae/frontal eye fields. The maps are aligned on bregma (arrow) and Layer V at the midline (the horizontal dashed line at 1 mm). The curved dashed line indicates the border between agranular (M1) and granular (S1) cortex in the fore- and hindlimb areas.