To determine whether RN glutamatergic neurons targeted by M1 neurons do indeed participate in anxiety-like behavior and CCL5 synthesis, we inject AAV1-hSyn-Cre, an anterograde transsynaptic virus, locally into M1 and AAV-CaMKII-DIO-GCaMP6s into the RN to allow Cre-dependent expression of GCaMP6s in RN neurons postsynaptic to M1 neurons (Fig. 6a). The gene discussed is CCL5; the disease is Anxiety.