Both animal studies and studies using deep brain stimulation in humans have demonstrated the involvement of the subthalamic nucleus (STN) in motivational and emotional processes; however, participation of this nucleus in processing human emotion has not been investigated directly at the single-neuron level. We analyzed the relationship between the neuronal firing from intraoperative microrecordings from the STN during affective picture presentation in patients with Parkinson's disease (PD) and the affective ratings of emotional valence and arousal performed subsequently. We observed that 17% of neurons responded to emotional valence and arousal of visual stimuli according to individual ratings. The activity of some neurons was related to emotional valence, whereas different neurons responded to arousal. In addition, 14% of neurons responded to visual stimuli. Our results suggest the existence of neurons involved in processing or transmission of visual and emotional information in the human STN, and provide evidence of separate processing of the affective dimensions of valence and arousal at the level of single neurons as well.

• Keywords
• arousal, basal ganglia, emotion, single neuron, subthalamic nucleus,
• MeSH
• Arousal * MeSH
• Emotions * MeSH
• Humans MeSH
• Neurons physiology   MeSH
• Subthalamic Nucleus physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The oculomotor role of the basal ganglia has been supported by extensive evidence, although their role in scanning eye movements is poorly understood. Nineteen Parkinsońs disease patients, which underwent implantation of deep brain stimulation electrodes, were investigated with simultaneous intraoperative microelectrode recordings and single channel electrooculography in a scanning eye movement task by viewing a series of colored pictures selected from the International Affective Picture System. Four patients additionally underwent a visually guided saccade task. Microelectrode recordings were analyzed selectively from the subthalamic nucleus, substantia nigra pars reticulata and from the globus pallidus by the WaveClus program which allowed for detection and sorting of individual neurons. The relationship between neuronal firing rate and eye movements was studied by crosscorrelation analysis. Out of 183 neurons that were detected, 130 were found in the subthalamic nucleus, 30 in the substantia nigra and 23 in the globus pallidus. Twenty percent of the neurons in each of these structures showed eye movement-related activity. Neurons related to scanning eye movements were mostly unrelated to the visually guided saccades. We conclude that a relatively large number of basal ganglia neurons are involved in eye motion control. Surprisingly, neurons related to scanning eye movements differed from neurons activated during saccades suggesting functional specialization and segregation of both systems for eye movement control.

• MeSH
• Antiparkinson Agents therapeutic use   MeSH
• Basal Ganglia drug effects   physiopathology   MeSH
• Reading MeSH
• Adult MeSH
• Globus Pallidus drug effects   physiopathology   MeSH
• Deep Brain Stimulation MeSH
• Electrodes, Implanted MeSH
• Levodopa therapeutic use   MeSH
• Middle Aged MeSH
• Humans MeSH
• Brain Mapping MeSH
• Microelectrodes MeSH
• Neurons pathology   MeSH
• Subthalamic Nucleus drug effects   physiopathology   MeSH
• Parkinson Disease drug therapy   physiopathology   MeSH
• Eye Movements * MeSH
• Pattern Recognition, Visual MeSH
• Aged MeSH
• Substantia Nigra drug effects   physiopathology   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antiparkinson Agents MeSH
• Levodopa MeSH