Effect of subthalamic nucleus interconnectivity at deep brain stimulation onset and offset: A simulation study

Deep brain stimulation (DBS) has been demonstrated to effectively improve the motor symptoms of Parkinson´s disease. However, the underlying mechanisms are not known. It has been reported that a period of time is required before the full effect on motor symptoms is realized after DBS is initiated and that suppression of symptoms persists after DBS ends under parkinsonian conditions. A computational model is presented to investigate the hypothesis that interconnectivity and transmission delays within the subthalamic nucleus (STN) neurons may induce a gradual decay and recovery of pathological oscillations at DBS onset and offset under simulated parkinsonian conditions. Interconnectivity strength between the STN neurons and the number of STN neurons directly stimulated by DBS are both varied to examine the gradual decay and recovery of oscillatory STN activity. Weaker interconnectivity and lower numbers of STN neurons directly receiving DBS input were found to result in longer decay and recovery times at the onset and offset of DBS, respectively.