Functional neuronal activity and connectivity within the subthalamic nucleus in Parkinson’s disease

ObjectiveCharacterization of the functional neuronal activity and connectivity within the subthalamic nucleus (STN) in patients with Parkinson’s disease (PD).MethodsSingle units were extracted from micro-electrode recording (MER) of 18 PD patients who underwent STN deep brain stimulation (DBS) surgery. The firing rate and pattern of simultaneously recorded spike trains and their coherence were analyzed. To provide a precise functional assignment of position to the observed activities, for each patient we mapped its classified multichannel STN MERs to a generic atlas representation with a sensorimotor part and a remaining part.ResultsWithin the sensorimotor part we found significantly higher mean firing rate (P < 0.05) and significantly more burst-like activity (P < 0.05) than within the remaining part. The proportion of significant coherence in the beta band (13–30 Hz) is significantly higher in the sensorimotor part of the STN than elsewhere (P =  0.015).ConclusionsThe STN sensorimotor part distinguishes itself from the remaining part with respect to beta coherence, firing rate and burst-like activity and postoperatively was found as the preferred target area.SignificanceOur firing behavior analysis may help to discriminate the STN sensorimotor part for the placement of the DBS electrode.

► Significantly different firing behavior of single units has been demonstrated in the sensorimotor part of the STN compared to the remaining part in PD patients. ► This includes increased mean firing rate, more bursty behavior of neurons and increased interneuronal coherences in the beta band. ► Postoperative evaluation of target stimulation areas in the investigated PD patients with DBS shows a significant preference for the sensorimotor part of the STN.