Objective: To provide evidence of early emotional processing at the single-neuron level in the STN.

Background: A fast response to coarse threat signals in the human amygdala demonstrated evidence for the phylogenetically old subcortical pathway which allows for a rapid response to biologically important events. Emotion related activity within the STN was invariably observed 300 ms after an emotional stimulus onset in local field potentials and single-neuron studies.[1,2] Given the position of the STN within the subcortical network, we hypothesised that early emotional processing may also take place in the STN.

Method: We recorded single-neuron activity from the STN during a presentation of a series of happy, fearful and neutral facial expressions (for 500 ms each) to 22 patients undergoing STN DBS for Parkinson’s disease. We detected and sorted spikes of individual neurons from within the STN and analysed their firing pattern in a time window of 0-500 ms after the picture onset using a bootstrap-based pairwise comparisons between the three facial expressions. The level of significance was set to 5% corrected for the three tests performed in each neuron.

Results: We identified 426 neurons in the STN, out of which the activity of only 6 neurons (1.4%) differed between the emotional categories (P < 0.05 corr.). The differences became insignificant after additional correction for the number of neurons considered.

Conclusion: We failed to demonstrate early subthalamic activity to emotional stimuli at a single-neuron level within the target motor part for DBS. The absence of short latency activity could reflect a delay due to previous processing of emotional related information either in the cortex and/or in the ventral basal ganglia before reaching the motor portion of the STN.  However, inherent methodological limitations to an intraoperative experiment could also be responsible for the negative result of the study. Supported by a grant from the Czech Science Foundation (GAČR 16-13323S) and Czech Ministry of Health (AZV 16-29651A), Progres Q27 project and by the Research Centre for Informatics, grant nr CZ.02.1.01/0.0/16 − 019/0000765.

References: [1] Sieger T, Serranova T, Ruzicka F, Vostatek P, Wild J, Stastna D, et al. Distinct populations of neurons respond to emotional valence and arousal in the human subthalamic nucleus. Proc Natl Acad Sci U S A 2015;112(10):3116-21. [2] Mendez-Bertolo C, Moratti S, Toledano R, Lopez-Sosa F, Martinez-Alvarez R, Mah YH, et al. A fast pathway for fear in human amygdala. Nat Neurosci 2016;19(8):1041-9.

« Back to 2019 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/no-evidence-for-early-emotional-processing-in-the-subthalamic-nucleus-a-single-neuron-study/