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 presenta-
tion 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 va-
lence 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.