Frontostriatal Cognitive Staging in Parkinson's Disease

Figure 2

Parkinson’s disease related frontostriatal cognitive dysfunction (PDFCD) staging with region-specific dopamine (DA) levels. Dopamine-related frontostriatal functioning is assumed to follow an inverted U-shaped dose-response curve. Predicted stage-specific dopaminergic function, both off and on dopaminergic treatment, is shown for dorsal caudate (d-Caud), ventral caudate (v-Caud), nucleus accumbens (NAcc) and frontal cortex. In the ON state, the inverted U-shaped curves represent DA levels if the patient is on levodopa, and DA tone if the patient is on a dopamine agonist. The direct dopaminergic projection to the frontal cortex seems to be initially upregulated, but with limited capability to increase further the dopaminergic tone in response to dopaminergic treatment (see text for details). ICDs = impulse control disorders.