Typical observations from single unit recordings obtained from the STN or GP in human patients with Parkinson’s disease or parkinsonian rendered animals include an increased neuronal firing rate, an increase in bursting activity, and more synchronised spiking activity (Galvan and Wichmann, 2008). The latter can also readily be observed in multiunit recordings as exaggerated levels of beta band oscillations. A recently identified biomarker is the occurrence of beta–gamma phase–amplitude coupling within primary motor cortex (de Hemptinne et al., 2013). We have demonstrated that beta–HFO PAC within STN can be added to the list of indicators of parkinsonian motor severity, albeit one that is highly related to beta band power.
