To shed light on delay-dependent changes of the BG response to cortical stimulation, we investigated how the transmission of transient cortical stimuli to the BG output nucleus (i.e., GPi) is mediated by delays in the indirect pathway, i.e., cortex → D2-MSN → GPe ⇌ STN → GPi pathway, both in the control and PD conditions. The gene discussed is GPI; the disease is Parkinson disease.