It is thought that the stage of illness, dosage of l-DOPA, frequency of l-DOPA treatment and the youth of the patient at the onset of symptoms; contributes to the severity of the involuntary movements associated with LID. In experiments employing real-time electrophysiological recordings in awake and active animals, LIDs have been shown to be strongly associated with cortical gamma-oscillations with accompanying Δc-fos overexpression, proposedly due to a dysregulation of dopamine signaling in the cortico-basal ganglia circuitry. This was concluded partially from reduced tyrosine hydroxylase (TH) staining in the cortex - and the fact that a dopamine receptor 1 antagonist, delivered exclusively to the cortex, relieved the dyskinesia at its peak-time. ΔFosB overexpression in the dorsal striatum (nigrostriatal dopamine pathway) via viral vectors generates levodopa-induced dyskinesia in animal models of Parkinson's disease. Dorsal striatal ΔFosB is overexpressed in rodents and primates with dyskinesias; moreover, postmortem studies of individuals with Parkinson's disease that were treated with levodopa have also observed similar dorsal striatal ΔFosB overexpression. Levetiracetam, an antiepileptic drug which has been demonstrated to reduce the severity of levodopa-induced dyskinesias, has been shown to dose-dependently decrease the induction of dorsal striatal ΔFosB expression in rats when co-administered with levodopa. Although the signal transduction mechanism involved in this effect is unknown. Nicotine (administered by dermal adhesive patches) has also been shown to improve Levodopa-induced dyskinesia and other PD symptoms. Patients with prominent dyskinesia resulting from high doses of antiparkinsonian medications may benefit from deep brain stimulation (DBS), which may benefit the patient in two ways: 1) DBS theoretically allows a reduction in l-DOPA dosage of 50–60% (tackling the underlying cause); 2) DBS treatment itself (in the subthalamic nucleus or globus pallidus) has been shown to reduce dyskinesia. Mavoglurant is also currently studied by Novartis for the treatment of this disease. On August 24, 2017 the FDA approved a drug to treat levodopa-induced dyskinesia for Parkinson's patients. The drug, Gocovri, is amantadine manufactured by Adamas Pharmaceuticals.