The homeodomain transcription factors Islet 1 and HB9 are expressed in adult alpha and gamma motoneurons identified by selective retrograde tracing
To study gene expression in differentiated adult motoneuron subtypes, we used fluorescent dextrans for both anterograde and retrograde axonal tracing in adult rat and mouse. Application of these dyes to the cut distal and proximal ends of small extramuscular nerve branches revealed both the peripheral ramifications and the cell bodies of subsets of motoneurons. We show that the soleus muscle is in
