Substantia Nigra and Subthalamic Nucleus Deep Brain Stimulation Exert Opposing Effects on Novelty Recognition in Parkinson's Disease

The study examined the effects of deep brain stimulation (DBS) on episodic memory in patients with Parkinson's disease. Stimulation of the substantia nigra increased recognition sensitivity and reduced false alarms at both frequencies. Conversely, subthalamic nucleus stimulation at 10 Hz reduced sensitivity and increased false alarms. Researchers identified a brain network associated with false recognition linking the nigra, globus pallidus, subthalamic nucleus, and regions of the medial temporal lobe, frontal, and occipital areas. The effects of DBS on reducing false alarms were related to modulation of this network and its baseline vulnerability state. The results suggest that DBS bidirectionally regulates recognition memory through target- and frequency-dependent connections between deep brain structures and cortex.