Conflict-dependent dynamic of subthalamic nucleus oscillations during moral decisions

Abstract

Although lesional, neuroimaging, and brain stimulation studies have provided an insight into the neural mechanisms of judgement and decision-making, all these works focused on the cerebral cortex, without investigating the role of subcortical structures such as the basal ganglia. Besides being an effective therapeutic tool, deep brain stimulation (DBS) allows local field potential (LFP) recordings through the stimulation electrodes thus providing a physiological "window" on human subcortical structures. In this study we assessed whether subthalamic nucleus LFP oscillations are modulated by processing of moral conflictual, moral nonconflictual, and neutral statements. To do so, in 16 patients with Parkinson's disease (8 men) bilaterally implanted with subthalamic nucleus (STN) electrodes for DBS, we recorded STN LFPs 4 days after surgery during a moral decision task. During the task, recordings from the STN showed changes in LFP oscillations. Whereas the 14--30 Hz band (beta) changed during the movement executed to perform the task, the 5--13 Hz band (low-frequency) changed when subjects evaluated the content of statements. Low-frequency band power increased significantly more during conflictual than during nonconflictual or neutral sentences. We conclude that STN responds specifically to conflictual moral stimuli, and could be involved in conflictual decisions of all kinds, not only those for moral judgment. LFP oscillations provide novel direct evidence that the neural processing of conflictual decision-making spreads beyond the cortex to the basal ganglia and encompasses a specific subcortical conflict-dependent component.

Ethical safety of deep brain stimulation: A study on moral decision-making in Parkinson's disease

“…We have previously shown that the modulation of STN neurophysiological activity is specifically involved in moral decisions in PD patients [23]. However, the modulation of STN activity does not imply a direct effect of STN DBS on moral decisions, since this can be mediated by other brain structures.…”

“…Here we aim to study whether STN DBS can affect moral decision-making by comparing PD patients in ON and OFF DBS conditions to those of PD patients without DBS implant during a moral task [23].…”

The Effects of Levodopa and Deep Brain Stimulation on Subthalamic Local Field Low-Frequency Oscillations in Parkinson's Disease

“…LFP studies investigating cognitive and emotional functions in the STN have found a specific LF modulation [14,17,49]. An LFP study recording STN LFPs in PD patients with and without depressive symptoms found a direct correlation between the STN LF band and emotions [50].…”

“…In patients with PD, LFPs can be recorded from the first choice target for DBS - the subthalamic nucleus (STN) [1]. STN LFP oscillations are specifically modulated during movement, during cognitive and behavioral tasks, and by various treatments [3,9,11,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. Pathophysiological LFP rhythms recorded from the STN in parkinsonian patients oscillate in the low-frequency (LF) band (2-7 Hz) [15], beta band (8-30 Hz) [19,20], gamma band (60-90 Hz) [27] and high-frequency band (>200 Hz) [28,29,30].…”

Keeping the human: neuroethics and the conciliation of dissonant values in the 21st century

“…Of considerably greater import, however, and no less remarkable, is the demonstrable ability to effect changes in the capacities for decision making and in the execution of moral judgments. [74][75][76][77][78][79][80][81] While current protocols indicate that neuroenhancement effects are only transient and observed only in the laboratory, it remains theoretically possible for prolonged daily stimulation to increase the duration and intensity of such effects with resultant long-term behavioral effects. Theoretically, therefore, neurostimulation methods can lead to their abuse and to a dependence on them.…”