SYN1 and migraine disorder: Furthermore, to validate the Kv1.4 channel as a pivotal target for the migraine pain-relieving response of TAAR1 signaling, we induced Kv1.4 expression specifically in TG neurons using a neuron promoter (human synapsin 1 gene promoter)-specific combinatorial lentiviral vector lenti-hSyn-Kv1.4-up (lenti-Kv1.4-up) containing enhanced green fluorescent protein (EGFP) as an expression marker.