Figure 6.

Proposed mechanism of motor disturbances. Excitation/inhibition imbalance, loss of autoinhibition, and SK channels downregulation disturbs cytoplasmic Ca²⁺ homeostasis in AADC deficiency SNc DA neurons (KI). Basal firing slows, the DA deficiency in the putamen worsens, and motor disturbances occur. Gene therapy treatment (KI-AAVN) reverses these electric abnormalities and relieves the symptoms of mice. However, the insufficient levels of serotonin may gradually, and repeatedly, influence the DA neurons and cause irregular firing patterns, which then lead to motor disturbance [rhythmic oculogyric crisis (OGC)].