motor neuron, leg motor neuron, T1 leg motor neuron, Azevedo Lesser Mark Phelps et al. 2022, right soma, V2 bundle, soma in T1, primary class, motor neuron, leg motor neuron, publication, soma side, T1 leg motor neuron, soma segment, V3_T1R, extracoxal_trochanter_depressor_in_thorax_Vn