Geremia et al. (2007) have proved that brief stimulation can increase the expression of GAP-43 and BDNF, thus achieving the effect of motor neuron regeneration. Cheng et al. (2014) found that selective light stimulation of the primary motor cortex can promote functional recovery of stroke rats due to increased expression of activity-dependent contralesional cortical neurotrophic factors including BDNF and NGF. The gene discussed is NGF; the disease is stroke disorder.